To see the other types of publications on this topic, follow the link: Characterization of Nickel.
Dissertations / Theses on the topic 'Characterization of Nickel'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Characterization of Nickel.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Bansa, Patrice B. "Property characterization of CVD nickel." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63137.pdf.
Full text
2
Hissam, Jason C. "Characterization of nickel-substituted hexaaluminate catalysts." Morgantown, W. Va. : [West Virginia University Libraries], 2008. https://eidr.wvu.edu/etd/documentdata.eTD?documentid=5999.
Full textAbstract:
Thesis (M.S.)--West Virginia University, 2008.Title from document title page. Document formatted into pages; contains vii, 78 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 74-76).
3
CORTEZ, ORFELINDA AVALO. "SYNTHESIS AND CHARACTERIZATION OF NANOSTRUCTURED IRON-NICKEL ALLOYS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=12975@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
Oxido de níquel e hematita nanoestruturadas foram sintetizadas a partir da decomposição térmica de nitrato de níquel hexahidratado e nitrato férrico nonahidratado respectivamente, na faixa de temperatura de 350-450°C com variações no tempo reacional. Os tamanhos de cristalito do NiO e Fe2O3 foram estimados a partir dos difractogramas de Difração de Raios-X (XRD) utilizando os software PowderCell e Topas. Foi observado que o tamanho de cristalito varia em função da temperatura de sínteses. O resultado mais significante foi observado nos cristalitos de NiO os quais aumentam de 31 nm (T=350°C, 3hr) a 98 nm (T=450°C, 5hr). Foram realizados estudos cinéticos da redução NiO e Fe2O3 por hidrogênio na faixa de temperatura de 250-600°C. Ligas ferroníquel nanoestruturadas com composições FexNi100-x (x = 25, 50, and 75 w%) têm sido preparadas com sucesso por decomposição térmica de nitratos (formação de óxidos) e posterior redução com hidrogênio a 700ºC (formação das ligas). As ligas Fe-Ni, caracterizadas por difração de raios-X mostraram tamanhos de cristalito da ordem de 25nm. A fase rica em Ni, liga Fe25Ni75, apresentou uma estrutura γ(FCC). A liga Fe50Ni50 apresentou a existência de uma estrutura tetragonal. A fase rica em Fe, liga Fe75Ni25, contém uma mistura de fases α(BCC) e γ(FCC). A coexistência das fases e atribuída à segregação de fases que acontece nestas ligas como resultado da difusão atômica. A partir dos resultados das medições magnéticas efetuadas a 300K, pode-se estabelecer que as ligas Fe-Ni nanoestruturadas tem um comportamento superparamagnético.
Nickel oxide and hematite nanostructured were successfully prepared by thermal decomposition from nickel nitrate hexahydrate and ferric nitrate nonahydrate in the temperature range of 350-450°C with variation of the time. The average crystallite sizes of NiO and Fe2O3 were estimated from X-ray diffraction (XRD) peaks using the PowderCell and Topas software. We observed that the crystallite size changes as a function of synthesis temperature. The significant result was the large size of the resulting NiO crystallites, which increased from 31nm (T=350°C, 3hr) to 98nm (T=450°C, 5hr). Kinetic studies of the reduction of NiO and Fe2O3 by hydrogen in the temperature range 250-600°C have been investigated. Nanostructured Fe-Ni alloys with compositions FexNi100-x (x = 25, 50, and 75 w%) have been successively prepared by thermal decomposition from mixtures of nitrates (formation of oxides) and reduction by hydrogen at 700ºC (formation of alloys). The Fe-Ni alloys, characterized by X-ray diffraction show crystallites sizes about 25nm. The Nirich phase, Fe25Ni75 alloys show the existence of γ(FCC) phase. The Fe50Ni50 alloy show the existence of tetragonal phase. The Fe-rich phase, Fe75Ni25 alloy, contain a mixture of α(BCC) and γ(FCC) phases. The coexistence of these phases is attributed to phase segregation occurring in these alloys as a result of enhanced atomic diffusion. It was inferred from results of magnetic measurements at 300K, that nanostructured Fe-Ni alloys were in a superparamagnetic state.
4
Silva, Cauê Corrêa da. "Manufacturing and characterization of aluminium-nickel matrix composites." reponame:Repositório Institucional da UFSC, 2015. https://repositorio.ufsc.br/xmlui/handle/123456789/162713.
Full textAbstract:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2015.Made available in DSpace on 2016-05-24T17:40:40Z (GMT). No. of bitstreams: 1 338916.pdf: 1608467 bytes, checksum: 23dec638e6d54767a7815bbbc05e726e (MD5) Previous issue date: 2015
Abtsract : The present work describes the designing of a manufacturing process for the production of aluminum matrix composites reinforced with carbon fibers. The matrix was chosen to be an interlayering of aluminum foils and nickel mesh stripes, cold rolled with 70% of thickness reduction, being then submitted to different heat treatments, of which immersion in pure aluminum melt was found to be the most promising. Microstructure and composition of the samples were analyzed with scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractography and microhardness test, whose results showed the presence of remaining nickel and intermetallic compounds formed during the processing, namely Ni2Al3 and NiAl, agreeing with studies on reactive diffusion found in the literature. Furthermore, composites were produced by incorporating nickel-coated carbon fibers to the manufacturing process, being evaluated the effect of the fibers addition to the material with scanning electron microscopy, energy-dispersive Xray spectroscopy, X-ray diffractography and fiber content estimation via image binarization. Intermetallic phases were also present in the microstructure of the composites, nevertheless in smaller extent and in an aluminum matrix. Bond between matrix and fibers was found to be strong, since no fiber pull out took place. Performed fiber content analysis showed that the optimum fiber volume content is between 15% and 40%. Mechanical properties of both without and with fibers materials were assessed through 4-point bending tests, having theirfracture surface analyzed afterwards.
O presente trabalho descreve o desenvolvimento de um processo de fabricação para a produção de compósitos de matriz de alumÃnio reforçados com fibras de carbono. O material escolhido para a matriz era constituÃdo por camadas intercaladas de folhas de alumÃnio e malha de nÃquel, laminadas a frio com 70% de redução de espessura, sendo então submetidos a diferentes tratamentos térmicos, dentre os quais imersão em fundido de alumÃnio mostrou-se o mais promissor. A microestrutura e a composição das amostras foram analisadas com microscopia eletrônica de varredura, espectroscopia dispersiva de raios-X, difratografia de raios-X e testes de microdureza, cujos resultados mostraram a presença de nÃquel remanescente e compostos intermetálicos, Ni2Al3 e NiAl, coincidindo com estudos sobre difusão reativa encontrados na literatura. Além disso, compósitos foram produzidos através da incorporação de fibras de carbono revestidas com nÃquel ao processo de fabricação, sendo avaliados os efeitos da adição de fibras ao material com microscopia eletrônica de varredura, espectroscopia dispersiva de raios-X, difratografia de raios-X e estimativa do teor de fibras através de binarização de imagens. Fases intermetálicas também estavam presentes na microestrutura do compósito, entretanto em menor quantidade e em uma matriz de alumÃnio. A adesão entre matriz e fibras foi avaliada como sendo alta, visto que não ocorrou o fenômeno de pull out das fibras. As análises de teor de fibra mostraram que o volume de fibras ótimo encontra-se entre 15% e 40%. Tanto propriedades mecânicas do material sem fibra, quanto do com fibra, foram aferidos com teste de flexão em 4 pontos, posteriormente tendo sua superfÃcie de fratura analisada.
5
Silva, Cauê Corrêa da. "Manufacturing and characterization of aluminium-nickel matrix composites." reponame:Repositório Institucional da UFSC, 2015. https://repositorio.ufsc.br/xmlui/handle/123456789/169520.
Full textAbstract:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia Mecânica, Florianópolis, 2015.Made available in DSpace on 2016-10-19T13:04:45Z (GMT). No. of bitstreams: 1 338916.pdf: 1608467 bytes, checksum: 23dec638e6d54767a7815bbbc05e726e (MD5) Previous issue date: 2015
Abtsract : The present work describes the designing of a manufacturing process for the production of aluminum matrix composites reinforced with carbon fibers. The matrix was chosen to be an interlayering of aluminum foils and nickel mesh stripes, cold rolled with 70% of thickness reduction, being then submitted to different heat treatments, of which immersion in pure aluminum melt was found to be the most promising. Microstructure and composition of the samples were analyzed with scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffractography and microhardness test, whose results showed the presence of remaining nickel and intermetallic compounds formed during the processing, namely Ni2Al3 and NiAl, agreeing with studies on reactive diffusion found in the literature. Furthermore, composites were produced by incorporating nickel-coated carbon fibers to the manufacturing process, being evaluated the effect of the fibers addition to the material with scanning electron microscopy, energy-dispersive Xray spectroscopy, X-ray diffractography and fiber content estimation via image binarization. Intermetallic phases were also present in the microstructure of the composites, nevertheless in smaller extent and in an aluminum matrix. Bond between matrix and fibers was found to be strong, since no fiber pull out took place. Performed fiber content analysis showed that the optimum fiber volume content is between 15% and 40%. Mechanical properties of both without and with fibers materials were assessed through 4-point bending tests, having theirfracture surface analyzed afterwards.
O presente trabalho descreve o desenvolvimento de um processo de fabricação para a produção de compósitos de matriz de alumínio reforçados com fibras de carbono. O material escolhido para a matriz era constituído por camadas intercaladas de folhas de alumínio e malha de níquel, laminadas a frio com 70% de redução de espessura, sendo então submetidos a diferentes tratamentos térmicos, dentre os quais imersão em fundido de alumínio mostrou-se o mais promissor. A microestrutura e a composição das amostras foram analisadas com microscopia eletrônica de varredura, espectroscopia dispersiva de raios-X, difratografia de raios-X e testes de microdureza, cujos resultados mostraram a presença de níquel remanescente e compostos intermetálicos, Ni2Al3 e NiAl, coincidindo com estudos sobre difusão reativa encontrados na literatura. Além disso, compósitos foram produzidos através da incorporação de fibras de carbono revestidas com níquel ao processo de fabricação, sendo avaliados os efeitos da adição de fibras ao material com microscopia eletrônica de varredura, espectroscopia dispersiva de raios-X, difratografia de raios-X e estimativa do teor de fibras através de binarização de imagens. Fases intermetálicas também estavam presentes na microestrutura do compósito, entretanto em menor quantidade e em uma matriz de alumínio. A adesão entre matriz e fibras foi avaliada como sendo alta, visto que não ocorrou o fenômeno de pull out das fibras. As análises de teor de fibra mostraram que o volume de fibras ótimo encontra-se entre 15% e 40%. Tanto propriedades mecânicas do material sem fibra, quanto do com fibra, foram aferidos com teste de flexão em 4 pontos, posteriormente tendo sua superfície de fratura analisada.
6
Mwania, Tom Muinde. "Synthesis and characterization of nickel imine/amine complexes; a possible model for nickel superoxide dismutase." Thesis, Wichita State University, 2012. http://hdl.handle.net/10057/5416.
Full textAbstract:
Superoxide dismutases are ubiquitous enzymes that efficiently catalyze the disproportionation of superoxide radical anions to protect biological molecules from oxidative damage. Several SODs have been identified having different metals at their active sites. These include Mn SOD, Fe SOD, Cu/Zn SOD and, most recently, Ni SOD. The catalytic center of Ni SOD resides in the N-terminal active-site loop, where a Ni(II) is coordinated by the amine N of His-1, the amide N of Cys-2, and two thiolate S atoms of Cys-2 and Cys-6. In the oxidized form, Ni(III) adds the imidazole N of His-1 as an axial ligand. For the past decade, we have been developing methodology using 2, 2’-dithiodibenzaldehyde (DTDB) for the synthesis of metal complexes with mixed N/S coordination. We are reporting on the application of this methodology to the synthesis of model complexes for the active site of NiSOD, in which we have successfully synthesized and characterized three NiIIN2S2 complexes of imine/amine N donors: Ni(NNS)SPh (1), Ni(NNS)SPhNO2 (2) and Ni(NNS)StBu (3). These may be used as a model for reduced NiSOD, with future plans of comparing to complexes with amide/amine N donors, thus establishing the role of the amide.Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Chemistry
7
Arslan, Hulya. "Synthesis And Characterization Of Nickel Based Bulk Amorphous Alloys." Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/3/12605099/index.pdf.
Full textAbstract:
The aim of this study is to synthesize and characterize new bulk amorphous alloys in the Ni- based systems. Theoretical studies on the basis of semi-empirical rules and the electronic theory of alloys in pseudopotential approximation has been provided in order to predict the impurity elements that will lead to an increase in the glass forming ability of Ni-based alloy systems. Glass forming ability of ten different compositions of alloys of Ni-Nb, Ni-Fe, Ni-B, Ni-Hf and Ni-Cr was simulated by using FORTRAN programs based on pseudopotential theory. In addition to the binary alloys, ternary alloys, which were formed by addition of 1 at% of third element to these systems, were also simulated. Since ordering energy is an indicator of glass forming ability, theoretical studies allowed to predict the effect of various third elements on the formation of amorphous phase. Furthermore, ordering energies were also used to calculate other parameters important for glass forming ability. In the second part of the study, on the basis of theoretical results, a series of casting experiments were done. Different compositions of Ni-Nb, Ni-Nb-Sn and Ni-Nb-Al alloys were cast in the centrifugal casting machine. Alloys were melted in alumina crucibles and cast into the copper moulds. Characterizations of cast alloys were done by the use of Metallography, SEM, XRD and DSC. Fully amorphous Ni52Nb41Al7 alloy was synthesized in bulk form with 0.8 mm thickness.
8
Huang, Shiliang. "Open-Framework Germanates and Nickel Germanates : Synthesis and Characterization." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75495.
Full textAbstract:
Microporous materials have a wide range of important applications in separation, gas adsorption, ion-exchange and catalysis. Open-framework germanates are a family of microporous compounds and are of particular interest. This thesis focuses on the synthesis and characterization of new open-framework germanates as well as introducing the transition-metal nickel into germanate structures. One new microporous germanosilicate, SU-78 and four new open-framework germanates, SU-74, SU-75, SU-69 and SU-76 have been obtained by using organic molecules as structure directing agents (SDAs). The incorporation of nickel and organic SDAs in the synthesis resulted in five novel nickel germanates, SUT-1, SUT-2, SUT-3, SUT-4 and SUT-5, in which nickel complexes act either as framework-forming components or as structure directing agents. The general synthesis route is described and the variables that affect the synthesis products are summarized. Different techniques applied on the characterization of chemical and physical properties of the products are also introduced.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Submitted. Paper 2: Submitted. Paper 3: Submitted. Paper 5: Manuscript.
9
Bahr, Douglas. "Fracture mechanics characterization of a single crystal nickel alloy." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/19604.
Full text
10
Karim, Salma. "Preparation and characterization of supported and unsupported nickel complexes." Thesis, Brunel University, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.290951.
Full text
11
Colebrook, Marjorie Helen. "Rheology and electro-acoustic characterization of laterite slurries." Thesis, University of British Columbia, 2008. http://hdl.handle.net/2429/2454.
Full textAbstract:
A systematic research study was carried out in order to characterize the rheology of concentrated slurries prepared from eight nickel laterites. The experiments were carried out using a rotational viscometer, and the behavior of the laterites was evaluated in terms of the apparent viscosity and yield stress obtained through flow curve modeling.
An attempt was made to correlate the results obtained for the laterite samples with data obtained for model single mineral systems as well as for model mixed mineral systems. In combination with detailed mineralogical characterization of the laterite samples, all the rheological results allowed a rheology-based laterite classification system to be proposed. Accordingly, the laterite samples gave the following responses: the SAPSIL samples (high-quartz) generally producedl ow yield stress values, the SAPFE samples (high-iron) were characterized by intermediate to high yield stress values, while the SAP samples (saprolite) gave the highest yield stress values. Interestingly, these dominant rheological responses of laterites could actually be predicted based on rheological tests carried out on model mineral suspensions (particularly goethite and quartz).
Since the rheology of fine mineral suspensions is largely determined by the surface properties (surface charge) of the particles, a series of electro-acoustic measurements were also performed on model minerals and laterite samples to analyze the surface charge characteristics of the tested samples. It was demonstrated that the current electro-acoustic theory developed for single mineral systems can readily be used for modeling the behavior of mixed mineral systems. The modeling and experimental data agreed exceptionally well when constituent minerals were of the same surface charge under given pH. Clear but rather small deviations between experiment and theory were observed under conditions when the minerals were oppositely charged. This observation strongly suggested that inter-particle aggregation was most likely responsible for the observed discrepancies.
Overall, the results of this thesis show that laterite slurries exhibit a wide range of rheological responses due to highly variable mineralogy, differences in particle size distributions, and difference in the surface properties of the many constituent minerals. It also shows that the surface properties of the minerals relates to rheology.
12
Kaya, Irfan. "SHAPE MEMORY BEHAVIOR OF SINGLE AND POLYCRYSTALLINE NICKEL RICH NICKEL TITANIUM ALLOYS." UKnowledge, 2014. http://uknowledge.uky.edu/me_etds/37.
Full textAbstract:
NiTi is the most commonly used shape memory alloy (SMA) and has been widely used for bio-medical, electrical and mechanical applications. Nickel rich NiTi shape memory alloys are coming into prominence due to their distinct superelasticity and shape memory properties as compared to near equi-atomic NiTi shape memory alloys. Besides, their lower density and higher work output than steels makes these alloys an excellent candidate for aerospace and automotive industry. Shape memory properties and phase transformation behavior of high Ni-rich Ni54Ti46 (at.%) polycrystals and Ni-rich Ni51Ti49 (at.%) single-crystals are determined. Their properties are sensitive to heat treatments that affect the phase transformation behavior of these alloys.
Phase transformation properties and microstructure were investigated in aged Ni54Ti46 alloys with differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) to reveal the precipitation characteristics and R-phase formation. It was found that Ni54Ti46 has the ability to exhibit perfect superelasticity under high stress levels (~2 GPa) with 4% total strain after 550°C-3h aging. Stress independent R-phase transformation was found to be responsible for the change in shape memory behavior with stress.
The shape memory responses of [001], [011] and [111] oriented Ni51Ti49 single-crystals alloy were reported under compression to reveal the orientation dependence of their shape memory behavior. It has been found that transformation strain, temperatures and hysteresis, Classius-Clapeyron slopes, critical stress for plastic deformation are highly orientation dependent.
The effects of precipitation formation and compressive loading at selected temperatures on the two-way shape memory effect (TWSME) properties of a [111]-oriented Ni51Ti49 shape memory alloy were revealed. Additionally, aligned Ni4Ti3 precipitates were formed in a single crystal of Ni51Ti49 alloy by aging under applied compression stress along the [111] direction. Formation of a single family of Ni4Ti3 precipitates were exhibited significant TWSME without any training or deformation. When the homogenized and aged specimens were loaded in martensite, positive TWSME was observed. After loading at high temperature in austenite, the homogenized specimen did not show TWSME while the aged specimen revealed negative TWSME.
13
Aydogmus, Tarik. "Processing And Characterization Of Porous Titanium Nickel Shape Memory Alloys." Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612232/index.pdf.
Full textAbstract:
Porous TiNi alloys (Ti-50.4 at. %Ni and Ti-50.6 at. %Ni) with porosities in the range 21%-81% were prepared successfully applying a new powder metallurgy fabrication route in which magnesium was used as space holder resulting in either single austenite phase or a mixture of austenite and martensite phases dictated by the composition of the starting prealloyed powders but entirely free from secondary brittle intermetallics, oxides, nitrides and carbonitrides. Magnesium vapor do not only prevents secondary phase formation and contamination but also provides higher temperature sintering opportunity preventing liquid phase formation at the eutectic temperature, 1118 °C resulting from Ni enrichment due to oxidation. By two step sintering processing (holding the sample at 1100 °
C for 30 minutes and subsequently sintering at temperatures higher than the eutectic temperature, 1118 °
C) magnesium may allow sintering probably up to the melting point of TiNi. The processed alloys exhibited interconnected (partially or completely depending on porosity content) open macro-pores spherical in shape and irregular micro-pores in the cell walls resulting from incomplete sintering. It has been found that porosity content of the foams have no influence on the phase transformation temperatures while deformation and oxidation are severely influential. Porous TiNi alloys displayed excellent superelasticity and shape memory behavior. Space holder technique seems to be a promising method for production of porous TiNi alloys. Desired porosity level, pore shape and accordingly mechanical properties were found to be easily adjustable.
14
Le, Page Matthew Derek. "The synthesis, characterization, and reactivity of nickel 2-pyridylphosphine complexes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0018/NQ56574.pdf.
Full text
15
Uddin, Salah. "Surface charge characterization and flotation of an ultramafic nickel ore." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=107688.
Full textAbstract:
AbstractAbout 300 million tonnes of inferred Ni resource in ultramafic hosted rocks is present in 'Thompson Nickel Belt' in north central Manitoba. The processing challenges result from electrostatic interaction between pentlandite (the main Ni-mineral) and serpentine (the main gangue and one of the MgO minerals). As a contribution to meeting the challenge, the thesis examines the role of particle and bubble surface charge and the effect of fibre disintegration on flotation behavior of an ultramafic Ni ore sample. For surface charge characterization the sedimentation potential technique was used. A novel integrated device was developed to measure sedimentation potential, conductivity and pH simultaneously. Maxwell's model was used to calculate volume fraction of dispersed phase from conductivity, and zeta potential, when appropriate, was calculated from the Smoluchowski equation. The technique was validated by showing good agreement with iso-electric point for alumina, silica and bubble suspensions with electrophoresis measurements. The technique was extended to characterize mixed minerals including ultramafic ore, and bubbles in the presence of particles. The results provided some evidence of metal ion adsorption on particles and the possibility of non-hydrophobic particle attachment to bubbles. The latter was reinforced by visualization studies of a pendant bubble exposed to particle suspensions.A novel fibre disintegration strategy was devised combining both chemical (acid) and physical (grinding) treatment based on work to enhance carbon dioxide uptake by serpentine. Using HCl, subsequent conventional flotation (amyl xanthate, soda ash and MIBC) gave significantly improved results over the untreated ore. Using H2SO4, arguably the practical option led to flotation without collector due to elemental sulphur formation on pentlandite, and without frother due to high ionic strength solutions. Improved Ni grade-recovery with higher MgO mineral rejection was achieved. Structural changes in the fibres were followed using various spectroscopic techniques and a mechanism of fibre disintegration suggested.Environ 300 millions de tonnes de ressources inférées de Ni ultramafiques hébergé est présent dans 'ceinture nickélifère de Thompson' dans le centre-nord du Manitoba. Le traitement des défis résultant de l'interaction électrostatique entre pentlandite (le principal Ni-minéraux) et la serpentine. En tant que contribution à relever le défi, la thèse examine le rôle des particules et la charge de surface des bulles et l'effet de la désintégration des fibres sur le comportement de flottaison d'un échantillon de minerai de nickel ultramafiques. Pour la caractérisation de charge de surface de la technique de sédimentation potentielle a été utilisée. Un nouveau dispositif intégré a été développé pour mesurer le potentiel de sédimentation, la conductivité et le pH simultanément. Le modèle de Maxwell a été utilisée pour calculer la fraction volumique de phase dispersée de la conductivité, et le potentiel zêta, le cas échéant, a été calculée à partir de l'équation de Smoluchowski. La technique a été validée en montrant un bon accord avec l'iso-électrique de point pour les suspensions d'alumine, de silice et de bulles avec des mesures d'électrophorèse. La technique a été étendue afin de caractériser les minéraux mélangés, y compris de minerai ultramafiques, et des bulles dans la présence de particules. Les résultats ont fourni des preuves de ion métallique adsorption sur les particules et la possibilité de l'attachement des particules non-hydrophobe à bulles. Ce dernier a été renforcée par des études de la visualisation d'une bulle Pendentif exposés à des suspensions de particules.Une stratégie nouvelle fibre de désintégration a été conçu combinant à la fois chimique (acide) et physiques (broyage) un traitement basé sur le travail pour améliorer l'absorption du dioxyde de carbone par la serpentine. En utilisant HCl, à la suite de flottation conventionnelle (amyl xanthate, la cendre de soude et de MIBC) a donné des résultats nettement améliorés au cours des minerais non traités. Utiliser H2SO4, sans doute l'option la pratique conduit à de flottaison sans collecteur due à la formation du soufre élémentaire sur la pentlandite, et sans buse due à des solutions à haute force ionique. Amélioration de qualité Ni-reprise avec le rejet supérieur de MgO de a été atteint. Les changements structurels dans les fibres ont été suivis en utilisant diverses techniques de spectroscopie et d'un mécanisme de désintégration de fibre suggéré.
16
Robertson, Kevin. "Characterization of nickel hydroxide sludge using the variable pressure SEM." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80865.
Full textAbstract:
Acid mine drainage lime treatment sludge is characterized with the variable pressure scanning electron microscope. The major components are shown to be detrital material such as silicates and clay minerals and neutralization products such as gypsum and metal hydroxides.X-ray mapping and progressive sludge leaching experiments are performed to locate the major nickel bearing species. Progressive leaching was performed for two hours at pH 4, 3.5, and 3. It is observed that there is incomplete nickel extraction for all leach conditions. X-ray mapping establishes that the remaining nickel is due to minor amounts of Ni/S and Ni/O and more significantly colloidal sized nickel-silicon-aluminum complexes; which seem to result from neutralization.
Charge contrast imaging was also considered for characterization. It was studied on the mineral gibbsite to establish optimum working conditions for maximum contrast. Pressure, working distance, bias, scan rate and beam current are varied independently while the specimen current was monitored. Maximum contrast is shown to occur consistently at a specimen current of 3 nA. This implies that the user can operate over a wide range of conditions as long as the specimen current is maintained at its optimum value. This technique is then applied to the analysis of precipitated nickel hydroxides. Charge contrast proved not too informative because the particles are too small. Large electron doses at high magnifications can mask the subtle variation in local charging.
17
Botha, Ruan. "Design and characterization of asymmetrical porous nickel membranes / Ruan Botha." Thesis, North-West University, 2006. http://hdl.handle.net/10394/14.
Full textAbstract:
As an alternative to organic membranes, ceramic membranes are suitable for the chemical
industry due to their intrinsic thermal, chemical and mechanical stability. The centrifugal
dispositioning technique has the advantage that it produces membranes that are asymmetrical with
a smooth inner surface. In this study, nickel powders were used in the place of regular a-alumina
powders to produce an asymmetrical porous membrane, and to determine its characteristics.
Sub-micron nickel powders can be produced by the hydrothermal reduction of a nickel salt with
hydrazine. The particles obtained are of the correct size and size distribution and can be
processed to be suitable for centrifugal dispositioning. Dispersants like polyacrylamide-codiallyldimethylammoniumchloride,
polyvinylpirrolidone (PVP) and ammonium-polymetacrylate
(APMA) were investigated to determine their ability to stabilize Ni powder in an aqueous dispersion.
Nickel powder manufactured by the hydrothermal reduction of a nickel salt with hydrazine were
moulded into a tubular membrane by means or the centrifugal dispitioning technique. A stable
dispersion was made with PAAco with little agglomeration or segregation. The membranes were
successfully removed from the stainless steel moulds without breakage of the membrane. The
greencasted membranes obtained were sintered without membrane failure, where after they were
subjected to numerous tests to determine their characteristics.
SEM photographs were taken from the Inner surface and cross-sections to determine the
morphology of the membranes. It was demonstrated that a change in the crystal phase occurred at
1200"C, changing the morphology as well as the membrane characteristics. The nickel membrane
shrinkage during the sintering experiments was found to increase linearly. It was shown with
mercury intrusion that the bimodal pore size distribution of the membranes decreased with
increasing sintering temperature, while larger pores were exchanged for smatter pores. It was
found that water permeation varied from 5 to 69 L.m-2.h-1.bar-1, depending on the sintering
temperature (950°C to 1250°C) of the membrane. The water permeation decreased linearly with
increasing sintering temperature.Thesis (M.Sc. (Pharmaceutical Chemistry))--North-West University, Potchefstroom Campus, 2007.
18
Borkar, Tushar Murlidhar. "Processing and Characterization of Nickel-Carbon Base Metal Matrix Composites." Thesis, University of North Texas, 2014. https://digital.library.unt.edu/ark:/67531/metadc500026/.
Full textAbstract:
Carbon nanotubes (CNTs) and graphene nanoplatelets (GNPs) are attractive reinforcements for lightweight and high strength metal matrix composites due to their excellent mechanical and physical properties. The present work is an attempt towards investigating the effect of CNT and GNP reinforcements on the mechanical properties of nickel matrix composites. The CNT/Ni (dry milled) nanocomposites exhibiting a tensile yield strength of 350 MPa (about two times that of SPS processed monolithic nickel ~ 160 MPa) and an elongation to failure ~ 30%. In contrast, CNT/Ni (molecular level mixed) exhibited substantially higher tensile yield strength (~ 690 MPa) but limited ductility with an elongation to failure ~ 8%. The Ni-1vol%GNP (dry milled) nanocomposite exhibited the best balance of properties in terms of strength and ductility. The enhancement in the tensile strength (i.e. 370 MPa) and substantial ductility (~40%) of Ni-1vol%GNP nanocomposites was achieved due to the combined effects of grain refinement, homogeneous dispersion of GNPs in the nickel matrix, and well-bonded Ni-GNP interface, which effectively transfers stress across metal-GNP interface during tensile deformation. A second emphasis of this work was on the detailed 3D microstructural characterization of a new class of Ni-Ti-C based metal matrix composites, developed using the laser engineered net shaping (LENSTM) process. These composites consist of an in situ formed and homogeneously distributed titanium carbide (TiC) as well as graphite phase reinforcing the nickel matrix. 3D microstructure helps in determining true morphology and spatial distribution of TiC and graphite phase as well as the phase evolution sequence. These Ni-TiC-C composites exhibit excellent tribological properties (low COF), while maintaining a relatively high hardness.
19
Le, Thi Van Anh. "Characterization of poplar metal transporters to improve rehabilitation of metal polluted soils." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112004/document.
Full textAbstract:
La phytoremediation consiste à utiliser les plantes pour nettoyer des sols contaminés. Jusqu’ici, des plantes naturellement capables de tolérer et d’accumuler les polluants ont été utilisées pour cette approche. Cependant, l’utilisation de plantes transgéniques doit être considérée pour optimiser l’efficacité de la phytoremédiation. Le peuplier est une espèce adaptée pour la phytoremédiation et peut être utilisé pour des approches transgéniques. Néanmoins, son efficacité de phytoextraction est limitée par une forte accumulation de métaux dans les feuilles qui retournent au sol lors de leur chute. L’ingénierie génétique pourrait être utilisée pour résoudre ce problème, en modifiant l’expression de transporteurs de métaux soit pour limiter l’accumulation de métaux dans les feuilles, soit pour stimuler leur accumulation dans le bois.Dans le cadre de cette thèse, trois transporteurs potentiellement impliqués dans la tolérance et l’accumulation de métaux ont été caractérisés : PtIREG1, PtNRAMP3.1 et PtNRAMP3.2. L’expression de PtIREG1 chez la levure et chez Arabidopsis thaliana a montré que ce transporteur contribue à la tolérance au nickel. Des peupliers transgéniques chez lesquels l’expression de PtIREG1 est globalement augmentée ou ciblée dans le bois ont été générés. Des peupliers transgéniques chez lesquels l’expression de PtNRAMP3.1 ou PtNRAMP3.2 est modifiée ont également été générés au cours de cette thèse. Cela a permis de montrer que ces protéines fortement homologues ont des localisations subcellulaires distinctes : la membrane vacuolaire pour PtNRAMP3.2 et un compartiment connecté à l’appareil de Golgi pour PtNRAMP3.1. Des mesures de concentrations en métaux dans les feuilles des peupliers transgéniques ptNRAMP3.1 et PtNRAMP3.2 ont montré des différences avec le type sauvage non transformé, pour le cuivre, le manganèse, le cadmium et le zinc. Les résultats obtenus contribueront à l’élaboration de stratégies biotechnologiques pour réhabiliter les sols polluésPhytoremediation is the use of plants to clean up polluted soils. Previous approaches have mostly used native plants able to tolerate, degrade and accumulate environmental pollutants such as toxic metals, but transgenic plants may also be considered for phytoremediation in the future. Poplar is well adapted for phytoremediation and suitable for molecular genetic studies. However, high metal accumulation in poplar leaves limits phytoextraction due to toxic metal return to the soil after leaf abscission. In order to circumvent this problem, genetic engineering can be used to limit metal accumulation in leaves or direct metal accumulation in poplar trunks using relevant metal transporter genes under the control of tissue-specific promoters. This thesis focuses on the characterization of 3 candidate metal transporters potentially involved in metal tolerance and accumulation in poplar: PtIREG1, PtNRAMP3.1 and PtNRAMP3.2. Expression of PtIREG1 in yeast and in Arabidopsis thaliana indicated that it contributes to nickel tolerance. Transgenic poplars were generated in which PtIREG1is either ectopically overexpressed or expressed specifically in wood tissues. PtNRAMP3.1 and PtNRAMP3.2 transgenic plants were also generated during this thesis. Despite their high similarity, PtNRAMP3.1 and PtNRAMP3.2 displayed distinct localizations in poplar: PtNRAMP3.2 is targeted to the vacuolar membrane whereas PtNRAMP3.1 localizes in a compartment connected with the Golgi apparatus. Metal concentrations were modified in leaves of transgenic plants grown on metal-contaminated or non-contaminated soil. The results obtained will contribute to develop a biotechnological approach using transgenic plants for the rehabilitation in metal polluted soils
20
Werhun, Peter. "Nuclear Magnetic Resonance of Low-Receptivity Nuclides: The First Demonstration of 61Ni SSNMR as Applied to Structural and Crystallographic Characterization of Diamagnetic Nickel Complexes." Thesis, Université d'Ottawa / University of Ottawa, 2017. http://hdl.handle.net/10393/36525.
Full textAbstract:
Nuclear magnetic resonance (NMR) spectroscopy has proven to be an invaluable tool for the modern chemist, despite being a relatively insensitive spectroscopic technique. However, it is precisely this insensitivity that limits characterization of low-receptivity nuclides, which make up the bulk of transition metal nuclides, in particular. In this work, high-fields were used to collect the first 61Ni solid-state NMR (SSNMR) spectra of diamagnetic nickel compounds, specifically, bis(1,5-cyclooctadiene)nickel(0) (Ni(cod)2), tetrakis(triphenylphosphite)nickel(0) (Ni[P(OPh)3]4), and tetrakis(triphenylphosphine)nickel(0) (Ni(PPh3)4). This was complemented by NMR study of the co-ordinated ligands and 61Ni density functional theory (DFT) computations.
61Ni SSNMR spectra of Ni(cod)2 were used to determine its isotropic chemical shift (δiso = 965 ± 10 ppm), span (Ω = 1700 ± 50 ppm), skew (κ = -0.15 ± 0.05), quadrupolar coupling constant (CQ = 2.0 ± 0.3 MHz), quadrupolar asymmetry parameter (η = 0.5 ± 0.2), and the relative orientation of the chemical shift and EFG tensors. Solution study of Ni(cod)2 saturated in C6D6 yielded a narrow 61Ni signal, and the temperature dependence of δiso(61Ni) was assessed (δiso being 936.5 ppm at 295 K). The solution is proposed as a secondary chemical shift reference for 61Ni NMR in lieu of the extremely toxic Ni(CO)4 primary reference. For Ni[P(OPh)3]4, 61Ni SSNMR was used to infer the presence of two distinct crystallographic sites and establish ranges for δ¬iso in the solid state, as well as an upper bound for CQ (3.5 MHz for both sites). For Ni(PPh3)4, fitting provided a δiso value of 515 ± 10 ppm, Ω of 50 ± 50 ppm, κ of 0.5 ± 0.5, CQ of 0.05 ± 0.01 MHz, and η of 0.0 ± 0.2. Ni(cod)2 was chosen for study as it is a ubiquitous source of nickel(0), used for both further synthesis of nickel(0) compounds and directly as a catalyst. The study of Ni[P(OPh)3]4 and Ni(PPh3)4 demonstrated the utility of 61Ni SSNMR given the lack of a previously reported crystal structure for both and the transient nature of Ni(PPh3)4 in solution.
The work begins in Chapter 1 by introducing the interactions fundamental to NMR spectroscopy, before moving on to briefly review the field of transition metal nuclide NMR, the chemistry of nickel (with an emphasis on homogeneous catalysis with nickel(0)), and the literature with respect to nickel NMR up to this point. In Chapter 2, the theory and practice of NMR are explained, including solid-state NMR, as well as the basic principles of density functional theory NMR computations. The specific experimental and computational methods of this work are also introduced. Lastly, in Chapter 3 the results are discussed in the context of the concepts presented and literature reviewed, and highlight the use of 61Ni NMR as a means to gain novel information about the chemistry of the compounds studied.
21
Scheffler, Leopold. "Electrical characterization of transition metals in silicon:." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-165931.
Full textAbstract:
The understanding of the electrical properties of defects introducing deep levels in silicon is of prime technological importance in modern microelectronics. In this thesis, a comprehensive study of the transition metals titanium, cobalt, and nickel in silicon, and of their interaction with hydrogen is presented. The formed defects are detected and characterized by deep level transient spectroscopy (DLTS), Laplace DLTS, and minority carrier transient spectroscopy. A natural starting point for a study of metal-hydrogen reactions in silicon is the analysis of the effect of hydrogen on metal-free silicon. Complexes of hydrogen with carbon, which create deep levels in the band gap of silicon, are observed. Titanium introduces three levels into the band gap. The charge states determined in this thesis are in contradiction to the literature, questioning the assignment of these levels. Upon hydrogenation, TiH complexes with one, two, and three hydrogen atoms are identified. A proposition by theory that two different configurations of TiH with one hydrogen atom exist, can be supported. Cobalt is shown to have only one level in the band gap of silicon, whereas a second level previously attributed to cobalt is assigned to the cobalt-boron pair. Two CoH complexes are determined. Nickel has three levels in the band gap. Upon hydrogenation, complexes with up to three hydrogen atoms are identified. One of the defects can be observed in both n - and p -type silicon. For all three metals investigated, passive hydrogen complexes exist. They are created by further hydrogenation after the appearance of the above mentioned electrically active complexes. The thesis concludes with a comparison of the obtained results with those of neighboring elements to look for similarities and patternsDas Verständnis der elektrischen Eigenschaften von Defekten, welche tiefe Niveaus in der Bandlücke von Silizium erzeugen, ist von außerordentlichem Interesse für die moderne Mikroelektronik. In der vorliegenden Dissertation wird eine umfassende Untersuchung der Übergangsmetalle Titan, Kobalt und Nickel in Silizium und ihrer Wechselwirkung mit Wasserstoff vorgestellt. Die entstandenen Defekte werden mit Hilfe von Kapazitätstransientenspektroskopie (DLTS - deep level transient spectroscopy), Laplace DLTS und Minoritätsladungsträgertransientenspektroskopie (MCTS - minority carrier transient spectroscopy) beobachtet und charakterisiert. Für eine fehlerfreie Analyse der Metall-Wasserstoff-Reaktionen ist es sinnvoll, zuerst den Einfluss des Wasserstoffs auf metallfreies Silizium zu prüfen. Dabei wird die Bildung von Kohlenstoff-Wasserstoff-Komplexen, welche Niveaus in der Bandlücke von Silizium erzeugen, beobachtet. Titan besitzt drei Niveaus in der Bandlücke von Silizium. Die in dieser Arbeit bestimmten Ladungszustände stehen im Widerspruch zu den Literaturangaben, daher wird die Zuordnung dieser Niveaus in Frage gestellt. Die Reaktion von Titan mit Wasserstoff führt zu elektrisch aktiven Komplexen mit bis zu drei Wasserstoffatomen. Die Ergebnisse unterstützen einen Vorschlag aus der Theorie, nach dem der Komplex mit einem Wasserstoff zwei verschiedene Konfigurationen besitzen soll. Kobalt erzeugt ein Niveau in der Bandlücke. Ein weiteres Niveau, welches früher ebenfalls dem Kobalt zugewiesen wurde, kann dem Kobalt-Bor-Paar zugeordnet werden. Nach der Reaktion mit Wasserstoff können zwei CoH-Komplexe nachgewiesen werden. Nickel besitzt drei Niveaus in der Bandlücke und erzeugt elektrisch aktive NiH-Komplexe mit bis zu drei Wasserstoffatomen. Einer dieser Defekte kann sowohl im n - als auch im p -Typ Silizium beobachtet werden. Alle drei untersuchten Metalle besitzen elektrisch passive Komplexe, welche nach der weiteren Reaktion von Wasserstoff mit den aktiven Komplexen entstehen. Die Arbeit endet mit einem Vergleich der Ergebnisse mit denen benachbarter Elemente, um mögliche Ähnlichkeiten oder Muster zu erkennen
22
Bia, Francesca. "Surface characterization of electrosynthesized Nickel Hexacyanoferrate and other Prussian Blue Analogues." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/19190/.
Full textAbstract:
Prussian Blue Analogues (PBAs) are a class of inorganic compounds characterized by a porous, open and three-dimensional framework and that present several important electrochemical properties. In this work, a potentiodynamic protocol was adopted to synthesize nickel hexacyanoferrate films on a porous and low-cost substrate, Ni-foam. Performance of such films on Ni-foam as electrocatalysts in Oxygen Evolution Reaction (OER) was studied and evaluated – as development of cheap yet active OER catalysts is crucial for hydrogen production from the water splitting reaction. X-Ray Photoelectron Spectroscopy (XPS) was employed to study electrodeposited NiHCF films and a set of PBAs powders, which included both hexacyanoferrates and nitroprussides. This other last piece of work was valuable in finding out interesting features about plausible degradation process and structural differences in PBAs.
23
REZENDE, TATHIANA CARNEIRO DE. "GAMMA PRIME CHARACTERIZATION IN NICKEL BASE SUPERALLOYS THROUGH DIGITAL IMAGE ANALYSIS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6232@1.
Full textAbstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROEste trabalho consiste na caracterização da fase gama linha em superligas de níquel através do processamento e análise digital de imagens. Amostras de uma superliga de níquel foram submetidas a 10 tratamentos térmicos diferentes. Após o tratamento térmico, estas amostras foram preparadas para avaliação metalográfica e imagens da microestrutura foram adquiridas no microscópio eletrônico de varredura (MEV). A fase gama linha presente no material foi segmentada e posteriormente medida através do processamento digital de imagens. Foram analisadas 429 imagens, o que gerou medidas de mais de 225,000 partículas. Foi medida a fração de área ocupada pelas partículas de gama linha, a quantidade de partículas por imagem, a área de cada partícula e a razão de aspectos das partículas. Uma análise estatística dos resultados foi realizada. Os resultados mostraram menor concentração e maior tamanho de gama linha com o aumento da temperatura, conforme era esperado. O uso de análise digital de imagens permitiu obter medidas com altíssima confiabilidade, uma vez que a alta velocidade de análise permite uma amostragem muito superior às técnicas tradicionais de caracterização microestrutural.
This study consists of the characterization of the gamma prime phase in nickel base superalloys using digital image processing and analysis. Samples of a nickel base superalloy were heat treated to 10 different temperatures. After the heat treatment cycle, the samples were prepared for metallographic evaluation and images of the microstructure were acquired using a scanning electron microscope (SEM). The gamma prime was segmented and measured using digital image processing methods. 429 images were analyzed, in which over 225000 particles were measured. The following parameters were obtained: area fraction of gamma prime, number of particles of gamma prime per image, area of each particle and the particles' feret ratio. An statistical analysis of the data was performed The results showed that the gamma prime fraction decreases and its size increases with temperature increase, as expected. The use of digital image analysis provided measurements with high accuracy, as the high speed of digital image analysis allowed sampling much superior to the traditional microstructural characterization methods.
24
Al-Rashed, Rashed (Rashed Ahmed), and Marta Krason. "Fabrication and characterization of high surface area nickel-deposited graphite substrates." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/98824.
Full textAbstract:
Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, June 2015. First author.Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, June 2014. Second author.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 61-63).
In certain electrochemical battery cells, inefficiencies arise due to the formation of hydrogen from corrosion reactions at the anode. One way to reduce these inefficiencies is to operate the cell at high current densities, which is obtainable given a high cathode to anode surface area ratio; however, commercially available metal foams often do not provide sufficient surface area density (cm 2/g). Coating high-surface area materials in the appropriate metal is a premier alternative, but while methods to effectively coat two-dimensional substrates in metal through electrodeposition has been well documented, attempts to scale electrodeposition to three-dimensional coating to achieve high-surface area catalysts has encountered certain challenges. The formation of a pure metal crust on the outer surface area of the catalyst prevents the penetration of metal ions into the inner fibers of the material, resulting in a lower surface area density. This thesis describes simple, repeatable electrodeposition methods to increase the homogeneity of the nickel coating throughout highly porous graphite catalysts and prevent the formation of a metal crust. Parameters such as direct/pulsating current, ultrasonic vibration pretreatment, and varying electrodeposition solution concentrations were tested in order to optimize the electrodeposition procedure. Three techniques were used to characterize the post-synthesis surface condition including scanning electron microscopy, electron dispersive spectroscopy and cyclic voltammetry. The improved electrodeposition method led to nickel-coated graphite felt with a specific surface area of 620 cm2/cm 3 and a surface area density of 7500 cm2/g, achieving a 890% higher surface area and 4650% higher surface area density than commercially available nickel foams. The proposed electrodeposition method provides high-surface area, full-volume coating of highly porous catalysts, applicable not only to electrochemical batteries but to any battery chemistry with an electrolyte that contains fuels, particularly flow batteries. The proposed methods to obtain effective full-coated, high-surface area catalysts have the potential to optimize outputted battery power and thereby revolutionize battery electrode fabrication.
by Rashed Al-Rashed [and] Marta Krason.
S.B.
25
Chen, Chang-Nan. "Structure, characterization and kinetics of nickel complexes and reactions with biomolecules." Scholarly Commons, 2003. https://scholarlycommons.pacific.edu/uop_etds/2615.
Full textAbstract:
The macrocyclic square planar nickel complex, [Ni II CR] 2+ , has been shown to be a useful DNA or RNA structure probe due to its highly site- and conformation specific ability to induce cleavage on exposed guanine residues via the formation of a direct guanine N7-Ni III bond. Since the postulated intermediate [Ni III CR] 3+ is unstable, the detailed mechanism is unknown. In this study, the nature of the interaction of NiCR 2+ and its oxidized products with biomolecules was investigated. A study of the conversion of [Ni II CR] 2+ between a diamagnetic square planar structure and a paramagnetic tetragonal structure in aqueous solution has shown that the conversion is affected by the identity and the concentration of the counter anion. Of the anions studied, it is clear that Br − , ClO 4 − , and CF 3 SO 3 − have a higher ability to promote the conversion to the square planar form for [NiCR] 2+ than Cl − or CF 3 COO − . The oxidation reaction of [NiCR] 2+ with either KHSO 5 or Na 2 S 2 O 8 in a molar ratio of 1/1 resulted in the same stable complex [Ni(CR-2H)] 2+ . A single crystal x-ray diffraction study gave the structure of Ni(CR-2H)(ClO 4 ) 2 . In addition, kinetic studies revealed the oxidation reaction to be first order. The six protons on the two methyl groups of the macrocyclic ligand were also found to be sufficiently labile to exhibit hydrogen/deuterium exchange. The [Ni(CR-2H)] 2+ displays a higher acidity than [NiCR] 2+ by H/D exchange. This observation supports the conjecture that there is an enhanced dπ-pπ* back-bonding effect associated with the presence of the additional imine formed in [Ni(CR-2H)] 2+ . The [NI(CR-2H)] 2+ species with KHSO 5 also displays an oxidation ability similar to [NiCR] 2+ with KHSO 5 in the reaction with a 17 base pair synthetic oligonucleotide. This implies that [Ni(CR-2H)] 2+ is not just an oxidation product of [NiCR] 2+ , but may also play an important role in the reaction with guanine residues in oligonucleotides. The reactions of [NiCR] 2+ or [Ni(CR-2H)] 2+ with linoleic acid under a high concentration of Ni complexes (3.21 × 10 −3 M, 200 fold over linoleic acid) resulted in the unexpected reduced nickel complexes, (Ni 0 (CR-4H)-H + ) − - m/z 311.1 and (Ni 0 (CR-2H)-H + ) − - m/z 313.1, instead of the hydroperoxide product (HpODE-H + ) − - m/z 311.2.
26
Kelley, Murray 1965. "Scanning tunneling microscope characterization of nickel thin film nucleation and growth." Thesis, The University of Arizona, 1989. http://hdl.handle.net/10150/277130.
Full textAbstract:
A study of the nucleation, growth and final microstructure of vacuum deposited nickel films has been performed using scanning tunneling microscopy (STM) as the primary research instrument. Typical nucleation conditions are reported for nickel films grown on partially shadowed highly-oriented pyrolytic graphite (HOPG), and techniques are developed for using the STM to catalog film islands instead of more conventional electron microscopes. Values for the activation energy of surface diffusion, critical nucleus size, changes in the saturation nucleation density with temperature, and spatial variations in the nucleation rate are included. Roughening and microstructure changes observed with STM are reported as functions of substrate temperature and deposition angle for nickel films grown on highly-oriented pyrolytic graphite and fused silica. Conventional film RMS roughness values are compared to microRMS values derived from STM data and STM images of film microstructure are compared with SEM and optical microscope photographs.
27
Bowers, Matthew. "Characterization of Transformation-Induced Defects in Nickel Titanium Shape Memory Alloys." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417649766.
Full text
28
Salimian, Maryam. "Advances in multifunctional nickel/reduced graphene oxide nanocomposites, synthesis and characterization." Doctoral thesis, Universidade de Aveiro, 2018. http://hdl.handle.net/10773/23709.
Full textAbstract:
Doutoramento em Engenharia MecânicaO grafeno é constituído por uma monocamada de átomos de carbono dispostos numa espécie de rede hexagonal perfeita. Devido às suas propriedades extraordinárias, este nanomaterial tem suscitado um grande interesse tanto no setor científico como no industrial. A este respeito, a investigação em torno do grafeno mostrou um aumento exponencial em áreas tão diferentes como a energia, biomedicina, eletrónica, entre outras. O óxido de grafeno (GO), um dos derivados de grafeno, foi considerado como um substrato interessante para o desenvolvimento de nanocompositos. Isto deve-se fundamentalmente à presença de grupos funcionais de oxigénio na superfície do grafeno, os quais proporcionam locais reativos para a nucleação e o crescimento de outras estruturas. O níquel (Ni) é um metal de transição muito abundante na terra, possui uma superfície brilhante comum à maioria dos metais e é dúctil e maleável possuindo propriedades magnéticas e catalíticas superiores, condutividade térmica e elétrica razoáveis sendo muito utilizado em diferentes aplicações. As nanopartículas (NPs) de Ni são utilizadas como catalisadores heterogéneos e receberam atenção notável devido ao seu baixo custo, reduzida toxicidade, baixa corrosão, entre outras características. Desta forma, a funcionalização do GO com NPs de Ni pode constituir uma nova família de nanocompósitos com propriedades sinérgicas. Esta tese está focada no controlo da síntese de nanocompósitos Ni/GO, uma vez que o tamanho, a morfologia e a dispersão de NPs de Ni no grafeno afetam as suas funcionalidades e estão em dependência direta com as metodologias de síntese. Em primeiro lugar, foi usado um método hidrotérmico de fácil implementação e execução num passo único. Foram estudados vários parâmetros de síntese, incluindo temperatura, tempo de reação e agente redutor. O controlo destes parâmetros influenciou efetivamente o tamanho das NPs de Ni, variando estas de 150 a 900 nm, a morfologia variou de forma esférica a formato em espiga e de partículas finas bem distribuídas para agregados. Em seguida, o controlo do tamanho das NPs de Ni para valores inferiores a 10 nm e com distribuição de tamanho reduzido no substrato foi conseguido através de um procedimento de síntese em dois passos com base num método solvotérmico seguido por tratamento térmico sob atmosfera redutora de H2. O tempo de reação mostrou ser um fator chave para controlar a distribuição e o tamanho das NPs de Ni simultaneamente com a redução do GO (rGO). O aquecimento em atmosfera de H2 foi crucial para formar as NPs de Ni metálicas cristalinas. A influência de um tratamento térmico adicional em atmosferas redutora e inerte sobre a estrutura do nanocompósito Ni/rGO foi também investigada. Diferentes nanocompósitos apresentaram boa estabilidade térmica sob H2 até à temperatura de 450 °C durante 2 horas. O tratamento a 900 °C sob o fluxo de árgon alterou a estrutura do Ni/rGO por formação de “sulcos” através da rede de carbono e coalescência das NPs de Ni com formação de partículas maiores. O estudo das propriedades eletrofisicas dos nanocompositos Ni/rGO mostrou que estas são dependentes do tamanho e estrutura das NPs de Ni nas folhas de rGO. Esta é uma potencial vantagem do método de síntese desenvolvido para o design de diferentes nanocompositos de Ni/rGO que poderão ser materiais favoráveis para aplicação em dispositivos eletrónicos integrados.
Graphene, the world thinnest material made of carbon atoms in a dense honeycomb network has captured a great interest in both scientific and industry sectors due to its remarkable properties. In this regard, the graphene research is facing an incredible rise in different areas such as energy, biomedical, sensor and electronic applications, between others. Graphene oxide (GO), one of the graphene derivatives, has been considered as an interesting substrate to build nanocomposites. This is due to the presence of oxygen functionalities at the graphene surface which provides reactive sites for the nucleation and growth of other structures. Nickel (Ni) is a transition metal very abundant on earth, it has a shiny surface common to most metals and is both ductile and malleable possessing different properties such as superior magnetic and catalysis properties, a fairly good heat and electrical conductivity and is widely used in different areas of application. Ni nanoparticles (NPs) find use as heterogeneous catalyst and received noteworthy attention because of its inexpensive, non-toxic, low corrosion, waste minimization, between other characteristics. In this way, the functionalization of GO with Ni NPs can establish a new family of nanocomposites with synergic properties. This thesis is focused on the control of the synthesis of Ni/GO nanocomposites, since the size, morphology and dispersion of Ni NPs on graphene affect their functionalities and are in direct dependence with the synthesis methodologies. First, a facile one pot hydrothermal method was introduced and various synthesis parameters including temperature, reaction time and reducing agent were investigated. The control of these parameters effectively influenced the Ni size, ranging from 150 to 900 nm, the morphology from spherical to spiky shape and from well distributed fine particles to the big aggregation. Then, the control of the Ni NPs size to values of less than 10 nm with narrow size distribution on the substrate was achieved via a two-step synthesis procedure based on a solvothermal method followed by a heat treatment under H2 reducing atmosphere. The reaction time was shown to be a key factor to control the size and size distribution of Ni NPs simultaneously through the reduction of GO (rGO). Heating treatment under H2 was crucial to form the crystalized metallic Ni NPs. The influence of further thermal treatment under reducing and inert atmospheres on the structure of Ni/rGO nanocomposite was also investigated. Different nanocomposites showed a good thermal stability under H2 up to 450°C during 2 hours’ treatment. Higher temperature (900°C) under Argon flow changed the structure of Ni/rGO by formation of trenches through the carbon etching and coalescence of Ni NPs to form bigger particles. The study of the electrophysical properties of Ni/rGO showed that these properties are dependent on the size and structure of Ni NPs on rGO nanosheets. This is the potential advantage of the synthesis method developed for designing different matrix of Ni/rGO nanocomposites which could be a favorable material for integrated electronic devices application.
29
G, Kelekanjeri V. Siva Kumar. "Non-destructive Electrical Characterization of Controlled Waspaloy Microstructures." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/14561.
Full textAbstract:
In this research, controlled Waspaloy microstructures were produced with the objective of studying microstructural evolution in this alloy via electrically-based ac/dc non-destructive techniques. Correlations were developed between electrical measurements and alternate characterization techniques such as Ultra Small Angle X-ray Scattering (USAXS), Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) to gain a complete understanding of the microstructural transformations and the associated mechanisms. Three different sets of controlled microstructures were produced in this research. In Set I microstructures, matrix (gamma) grain sizes of 13, 52 and 89 micrometers were obtained after solution-treatments at 1045 and 176;C, 1090 and 176;C and 1145 and 176;C respectively. A vacancy stabilization treatment at 1045 and 176;C followed after which, the specimens were aged at 800 and 176;C for times ranging from 0.1 hrs to 100 hrs to vary the gamma prime precipitate size distribution. In Sets II and III, the solution-treatment was only conducted at 1145 and 176;C, with the stabilization treatment conducted only in Set II. Subsequently, aging experiments were conducted at 725 and 176;C (or 700 and 176;C in Set II), 800 and 176;C and 875 and 176;C for times up to 100 hrs.
DC four-point probe resistivity of specimens increased to a maximum upon initial aging from the solution-treated condition and showed a decreasing trend thereafter with successive aging. This, in addition to complementary evidence from SEM and USAXS, led to the conclusion that gamma prime nucleation-growth was complete by the time the resistivity maximum was observed. Resistivity variations that ensued upon successive aging after the maximum were attributed to microstructural/compositional changes due to gamma prime coarsening. The height of the maximum decreased drastically with increase in aging temperature from 725 and 176;C to 800 and 176;C, while the resistivity did not increase from the solution-treated condition upon aging at 875 and 176; C. Coarsening studies based on USAXS analysis indicated an LSW type volume diffusion mechanism of coarsening in Waspaloy, with an average coarsening rate constant of 3.25x10-29 [m3/sec] for Set I specimens aged at 800 and 176;C.
Analytical and Finite Element (FE) models of two-probe impedance and dc four-point probe resistivity methods were developed to gain insight into the measured response and the accurate determination of material properties.
AFM-based localized electrical examination of sub-grain Waspaloy microstructures was successfully conducted using electrostatic force microscopy (EFM), scanning Kelvin probe microscopy (SKPM) and current-AFM (I-AFM) electrical modes. I-AFM experiments revealed that the conductivity of the gamma prime phase was lower than that of the gamma phase.
30
Hicks, Tanya Temaca. "Preparation, characterization, and activity of mono-dispersed supported catalylsts [sic]." Available online, Georgia Institute of Technology, 2004:, 2004. http://etd.gatech.edu/theses/available/etd-07212004-102914/unrestricted/hicks%5Ftanya%5Ft%5F200412%5Fms.pdf.
Full textAbstract:
Thesis (M.S.)--Chemical Engineering, Georgia Institute of Technology, 2005.Agrawal, Pradeep K., Committee Chair ; Bommarius, Andreas S., Committee Member ; Schork, F. Joseph, Committee Member. Includes bibliographical references.
31
Wehner, Arno. "Growth and characterization of thin Al2O3 and Ga2O3 films on single-crystalline Ni, Co, and CoGa substrates." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971538360.
Full text
32
Bolshak, Evgeny. "Synthesis and characterization of nickel-based mixed oxides for ethanol steam reforming." Doctoral thesis, Universitat Rovira i Virgili, 2015. http://hdl.handle.net/10803/396313.
Full textAbstract:
En el projecte s'han avaluat els òxids mixtes de níquel-ferro-alumini, derivats de precursors amb estructura hidrotalcita, per a la producció d'hidrogen mitjançant reformat d'etanol amb vapor d'aigua. S'ha investigat la influència de diversos paràmetres: la relació níquel-ferro (de 3 a 0.5), la temperatura de calcinació del precursor de hidrotalcita (773 i 1073K), l'efecte de la temperatura de reacció (400°C, 500°C i 600°C) i la quantitat d'alumini en el sistema Ni-Fe-Al amb fórmula comuna Ni3Al1-xFex. S'ha determinat que una quantitat més gran de ferro (només fins a una relació Ni/Fe de 1) afecta positivament tant l'activitat com la selectivitat, a causa d'una millor dispersió del níquel metàl·lic i d’una menor deposició de carboni. Una temperatura de calcinació baixa indueix la formació d'un òxid mixt de níquel-ferro ben dispersat, mentre que una temperatura elevada condueixen a la formació d'una espinela. Aquesta última presenta una activitat menor i una desactivació ràpida. En comparació amb els sistema binaris purs (Ni3Al i Ni3Fe), els sistemes ternaris es van mostrar més eficaços per al reformat d'etanol, aconseguint de forma estable una selectivitat a hidrogen propera al 70% en proves de 100 h de reacció.n el proyecto se han evaluado los óxidos mixtos de níquel-hierro-aluminio, derivados de precursores con estructura hidrotalcita, para la producción de hidrógeno mediante reformado de etanol con vapor de agua. Se ha investigado la influencia de diversos parámetros: la relación níquel-hierro (de 3 a 0.5), la temperatura de calcinación del precursor de hidrotalcita (773 y 1073K), el efecto de la temperatura de reacción (400°C, 500°C y 600°C) y la cantidad de aluminio en el sistema Ni-Fe-Al con fórmula común Ni3Al1-xFex. Se ha determinado que una cantidad mayor de hierro (solo hasta una relación Ni/Fe de 1) afecta positivamente tanto la actividad como la selectividad, debido a una mejor dispersión del níquel metálico y a una deposición de carbono menor. Una temperatura de calcinación baja induce la formación de un óxido mixto de níquel-hierro bien dispersado, mientras que una temperatura elevada conducen a la formación de una espinela. Esta última presenta una actividad menor y una desactivación rápida. En comparación con los sistema binarios puros (Ni3Al i Ni3Fe), los sistemas ternarios se mostraron más eficaces para el reformado de etanol, alcanzando de forma estable una selectividad a hidrógeno cercana al 70% en pruebas de 100 h de reacción.
Nickel-iron-aluminum mixed oxides derived from hydrotalcite-like precursors have been evaluated in the steam reforming of ethanol for hydrogen production. Several different parameters have been studied: the influence of the nickel-to-iron ratio (from 3 to 0.5), the calcination temperature of the hydrotalcite precursor (773K and 1073K), the effect of reaction temperature (400°C, 500°C and 600°C) and amount of aluminium in Ni-Fe-Al system with common formula Ni3Al1-xFex. It has been found that a higher amount of iron (only till Ni/Fe=1 ratio) positively affects both activity and selectivity due to a better dispersion of metallic nickel and lower carbon deposition. Lower calcination temperature induces the formation of a well-dispersed nickel-iron mixed oxide, while higher calcination temperature lead to spinel crystallization. The latter exhibits a decreased activity and fast deactivation. Compared to pure binary systems (Ni3Al and Ni3Fe), the ternary systems showed the best performance in ethanol reforming, leading to a high and stable hydrogen selectivity of up to ca. 70% in 100 h-reaction tests.
33
Picciano, Nicholas. "Battery aging and characterization of nickel metal hydride and lead acid batteries." Connect to resource, 2007. http://hdl.handle.net/1811/25087.
Full textAbstract:
Thesis (Honors)--Ohio State University, 2007.Title from first page of PDF file. Document formatted into pages: contains viii, 139 p.; also includes graphics. Includes bibliographical references (p. 136-139). Available online via Ohio State University's Knowledge Bank.
34
Payton, Eric John. "Characterization and Modeling of Grain Coarsening in Powder Metallurgical Nickel-Based Superalloys." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1250265477.
Full text
35
Quintero, Soltero Oscar. "Microstructural characterization of overaged GTD-111 HP turbine buckets." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
Full text
36
Kim, Jong Kyong. "Characterization of Bacillus subtilis urease and the Klebsiella aerogenes UreEF protein." Diss., Connect to online resource - MSU authorized users, 2006.
Find full text
37
Mogorosi, Moses Mokgolela. "Synthesis and characterization of nickel, palladium and chromium complexes as olefin oligomerization catalysts." Doctoral thesis, University of Cape Town, 2009. http://hdl.handle.net/11427/6337.
Full textAbstract:
Includes abstract.Includes bibliographical references.
Has accompanying material on CD.
New N-functionalized 2-phosphinobenzaldimino (P^N) ligands (L) bearing 3-picolyl (41), furfuryl (42), thiophene-2-methyl (43), thiophene-2-ethyl (44), and benzyl (45) groups have been prepared in good yield. In addition, 2-iminopyridyl (N^N) (46), 2-bromobenzaldimino (47), and 2-phenoxyimino (O^N) (48) ligands and precursors, bearing furfuryl groups, were prepared in good yield. The amino analogues of 47 and 48 were obtained by reduction of the imine bonds using sodium borohydride. All compounds were fully characterized using spectroscopic and analytical techniques, including melting point, ¹H, ¹³C, and ³¹P NMR, IR spectroscopy, MS, and elemental analysis. These ligands (L) were reacted with appropriate metal precursors to give the corresponding metal complexes of the type PdLMeCl (51 – 55), PdLCl₂ (56 – 63), NiLBr₂ (75 – 82), and CrL(THF)Cl₃ (83 – 88).
38
Xu, Jinghao. "Alloy Design and Characterization of γ′ Strengthened Nickel-based Superalloys for Additive Manufacturing." Licentiate thesis, Linköpings universitet, Konstruktionsmaterial, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-173042.
Full textAbstract:
Nickel-based superalloys, an alloy system bases on nickel as the matrix element with the addition of up to 10 more alloying elements including chromium, aluminum, cobalt, tungsten, molybdenum, titanium, and so on. Through the development and improvement of nickel-based superalloys in the past century, they are well proved to show excellent performance at the elevated service temperature. Owing to the combination of extraordinary high-temperature mechanical properties, such as monotonic and cyclic deformation resistance, fatigue crack propagation resistance; and high-temperature chemical properties, such as corrosion and oxidation resistance, phase stability, nickel-based superalloys are widely used in the critical hot-section components in aerospace and energy generation industries. The success of nickel-based superalloy systems attributes to both the well-tailored microstructures with the assistance of carefully doped alloying elements, and the intently developed manufacturing processes. The microstructure of the modern nickel-based superalloys consists of a two-phase configuration: the intermetallic precipitates (Ni,Co)3(Al,Ti,Ta) known as γ′ phase dispersed into the austenite γ matrix, which is firstly introduced in the 1940s. The recently developed additive manufacturing (AM) techniques, acting as the disruptive manufacturing process, offers a new avenue for producing the nickel-based superalloy components with complicated geometries. However, γ′ strengthened nickel-based superalloys always suffer from the micro-cracking during the AM process, which is barely eliminated by the process optimization. On this basis, the new compositions of γ′ strengthened nickel-based superalloy adapted to the AM process are of great interest and significance. This study sought to design novel γ′ strengthened nickel-based superalloys readily for AM process with limited cracking susceptibility, based on the understanding of the cracking mechanisms. A two-parameter model is developed to predict the additive manufacturability for any given composition of a nickel-based superalloy. One materials index is derived from the comparison of the deformation-resistant capacity between dendritic and interdendritic regions, while another index is derived from the difference of heat resistant capacity of these two spaces. By plotting the additive manufacturability diagram, the superalloys family can be categorized into the easy-to-weld, fairly-weldable, and non-weldable regime with the good agreement of the existed knowledge. To design a novel superalloy, a Cr-Co-Mo-W-Al-Ti-Ta-Nb-Fe-Ni alloy family is proposed containing 921,600 composition recipes in total. Through the examination of additive manufacturability, undesired phase formation propensity, and the precipitation fraction, one composition of superalloy, MAD542, out of the 921,600 candidates is selected. Validation of additive manufacturability of MAD542 is carried out by laser powder bed fusion (LPBF). By optimizing the LPBF process parameters, the crack-free MAD542 part is achieved. In addition, the MAD542 superalloy shows great resistance to the post-processing treatment-induced cracking. During the post-processing treatment, extensive annealing twins are promoted to achieve the recrystallization microstructure, ensuring the rapid reduction of stored energy. After ageing treatment, up to 60-65% volume fraction of γ′ precipitates are developed, indicating the huge potential of γ′ formation. Examined by the high-temperature slow strain rate tensile and constant loading creep testing, the MAD542 superalloy shows superior strength than the LPBF processed and hot isostatic pressed plus heat-treated IN738LC superalloy. While the low ductility of MAD542 is existed, which is expected to be improved by modifying the post-processing treatment scenarios and by the adjusting building direction in the following stages of the Ph.D. research. MAD542 superalloy so far shows both good additive manufacturability and mechanical potentials. Additionally, the results in this study will contribute to a novel paradigm for alloy design and encourage more γ′-strengthened nickel-based superalloys tailored for AM processes in the future.Additional funding agencies: Agora Materiae Graduate School for multidisiplinary PhD students at Linköping University, and Stiftelsen Axel Hultgren.
39
Cuevas, Assunta Mariela. "Microstructure characterization of friction-stir processed nickel-aluminum bronze through orientation imaging microscopy." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2002. http://library.nps.navy.mil/uhtbin/hyperion-image/02sep%5FCuevas.
Full text
40
Bacon, Jeffrey W. "Synthesis and characterization of nickel-phenylphosphinidene and palladium-nickel clusters." 1994. http://catalog.hathitrust.org/api/volumes/oclc/32180523.html.
Full text
41
Jen-YiLin and 林真毅. "Growth and Characterization of Nickel Silicide Nanowires by Nickel Transported CVD." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/w55f33.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
102
Single crystalline NiSi2, Ni2Si, Ni31Si12 and Ni nanowire arrays coated with amorphous silicon dioxide were synthesized with high quantity by nickel transported chemical vapor deposition (CVD) method. Nickel (II) chloride hexahydrate (NiCl2•6H2O) was utilized as a single-source precursor and reacted with silicon substrate. The morphological changes with various reaction temperatures, ambient pressure and reaction time, were observed and studied, respectively. A plausible new growth mechanism via silicon diffusion in nickel was carry out by the observation of pure Ni nanowires grown at 400°C and the consumption of Si substrates. At 750°C and 850°C, cone-shaped nanowire arrays were formed composed of dense and oriented Ni31Si12 and Ni2Si nanowires with length over 60μm. Field emission measurements show that the turn-on field of the as-grown NiSi2, Ni2Si and Ni31Si12 nanowires were about 2.64V/μm, 2.28V/μm and 2.39V/μm, respectively. The field enhancement factor was measured to be 2476, 4561 and 4097, respectively, which is of potential applications as nanoscale field emitters. Moreover, ferromagnetic properties of Ni2Si and Ni31Si12 nanowire arrays were measured at low temperature, which provides diverse options in the use of biological materials.
42
Chao, Chung-Po, and 趙崇博. "Preparation and Characterization of Nickel Nanoparticles." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/26097949909046904565.
Full textAbstract:
碩士國立中正大學
化學暨生物化學研究所
102
Nanoparticles have a wide application because their magnetic properties are much different from the bulk materials. Thermal decomposition of organimetallic precursors was applied to synthesize Ni nanoparticles in this research. Bis(triphenylphosphine)dicarbonylnickel was used as their precursor and thermally decomposed to form a nickel atom in organic solvent. Changing the molar ratio of the precursor and the surfactant, the reaction temperature, solvent, reaction time, heating time can regulate the size and shape of the nanoparticles. It was found that the good dispersion of spherical Ni nanoparticles can be synthesized by using oleylamine and oleic acid two-surfactant system. We used transmission electron microscopy (TEM) to observe the shapes and particle size of nanoparticles and use energy dispersive spectroscopy (EDS), selected area electron diffraction (SAED), X-ray powder diffraction (XRD) to identify the composition and structure of the nickel nanoparticles. Finally, in magnetic properties,we used the vibrating sample magnetometer (VSM) and superconducting quantum interference device magnetometer(SQUID) to measure the magnetism. It was found that the 9 nm nickel nanoparticles appeared superparamagnetic properties and did not have coercivity at room temperature. The 18 nm and 24 nm nickel nanoparticles have coercivity and ferromagnetic properties at room temperature.
43
KUMAR, RAJESH. "SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF NICKEL ENCAPSULATED CARBON NANOTUBES." Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14578.
Full textAbstract:
ABSTRACT
The search for one dimensional materials to substitute silicon in electronic devices has
widened up in the past decade. Carbon nanotube is a promising material as it boasts of its
unique switching nature of conductivity from metallic to semiconducting according to its
geometry. In this project, the goal is to design and implement an optimized method for the
growth of Ni-encapsulated carbon nanotubes using thermal CVD and to characterize it using
standard available characterization techniques
44
Tseng, Chien-Lin, and 曾建霖. "Fabrication of Nickel Oxide and Nickel Sulfide by Electrodeposition and Their Characterization." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/26157433413477872033.
Full textAbstract:
碩士逢甲大學
電子工程所
99
The content of this thesis is to use the nickel nitrate, nickel chloride and nickel sulfate as the function of precursors respectively. The nickel oxide (NiO) and nickel sulfide (NiS) thin films were fabricated from the Ni film and ?Ni(OH)2 film deposited on ITO/Glass substrates by an electrodeposition technique. And the field emission scanning electron microscopy (FE-SEM) is used to observe the NiO and NiS surface morphology, structure and distribution. The crystal structures of the NiO and NiS were identified by X-ray diffraction (XRD). The energy dispersive spectrometer (EDS) is used to analysis NiS chemical composition.
45
HUANG, KAI, and 黃楷. "Synthesis and characterization of nickel oxide and nickel-copper oxide thin films." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/g6v8uc.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
105
Nickel oxide and copper-nickel oxide thin films have been successfully deposited by reactive ion beam sputter deposition. Experimental results show that nickel oxide deposited at 300C is single phase NiO while best crystalline quality is achieved with an Opf of 0.5. X-ray diffraction (XRD) analysis of nickel-copper oxide deposited at 300C shows a Ni2O3 like crystalline structure at low Opf while changes to NiO like crystalline structure at high Opf. Energy dispersive x-ray spectroscope (EDS) analysis shows that nickel-copper oxide deposited at low Opf is CuxNi2-xO3 with x = 1, while nickel-copper oxide deposited at high Opf is CuxNi1-xO with x = 0.5, which is supported by Raman analysis. The bandgap of NiO is ~ 3.5 eV regardless of Opf while the band gap of nickel-copper oxide decreases from 3.2 to 2.3 eV as Opf reaches 1.0.
46
Liu, Young-Chiang, and 劉永強. "Preparation and characterization of nickel oxide films." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/19331314447452643938.
Full textAbstract:
碩士大同大學
光電工程研究所
103
The stoichiometric NiO is an insulator, but the electric and optical properties of NiO were changed by effect of ionic nickel defect or oxygen interstitial. In this study, nickel defective and oxygen interstitial of NiO thin film were discussed from different properties of NiO thin films, which was fabricated by NiO target with conditions of various RF power, substrate temperature, oxygen content, post-deposition annealing by RF magnetron sputtering. In this experiment, we fabricated NiO films has semiconductor characteristics were confirmed by NiO diodes. The experimental results reveal that clear to change electric and optical properties as doping or post- deposition annealing. The conductivity of NiO thin films increases and the transmittance of NiO thin films decreases as oxygen content is increased, the conductivity of NiO thin films decreases and the transmittance of NiO thin films increases with post-deposition annealing. The NiO diodes has P-type semiconductor characteristics were fabricated from the NiO thin films were deposited in various oxygen content environment. The lowest Rs of the NiO thin film diode of 100% oxygen content is 3.82 x101, the current of NiO thin film diode at forward bias voltage increases as oxygen content is increased.
47
Chen, Hao-Long, and 陳晧隆. "Characterization of Sputtered Nickel Oxide Thin Films." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/63690322071078639216.
Full textAbstract:
博士國立成功大學
材料科學及工程學系碩博士班
93
Nickel oxide thin films with NaCl-type were deposited onto Corning glass substrates at different substrate temperatures by RF magnetron sputtering in a pure oxygen atmosphere. The relationships among substrate temperature, film thickness, and preferred orientation, surface morphology, and microstructure, structural, optical and electrical properties of NiO films were investigated. The resulting films were analyzed by grazing-incidence X-ray diffraction (GIXRD), ultrahigh resolution scanning electron microscope (HR-SEM), high-resolution transmission electron microscope (HR-TEM), atomic force microscopy (AFM), visible spectrum, four-point probe and Hall-effect measurements. The dependences of film properties on thickness effect, substrate temperature and aging effect were studied. The X-ray diffraction (XRD), Scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses of nickel oxide films indicate that these films are polycrystalline films. The variations of the microstructural parameters, such as crystallite size (L), stacking fault probability (α), strain (ε) and density (D), with film thickness and substrate temperature were investigated. The results show the crystallite sizes increaser as the thickness of the film increases. The variation of the dislocation density and the stacking fault probabilities and strain decrease as the thickness increases. The resistivity of NiO film is increased with an increase in film thickness and substrate temperature, which is related to the decrease of carrier concentration with film thickness and substrate temperature. Films deposited at lower deposition temperature region (< 473 K) develop a (111) preferred orientation. At higher deposition temperature, the (200) preferred orientation was developed. A model of developing preferred orientation was proposed in this paper. Electrical properties of NiO films were unstable and show an aging effect. Resistivity of NiO films increases as the time of natural aging increases. Oxygen or another gas chemisorption and reaction with NiO films are used to explain in aging of the NiO films in oxygen and atmosphere. Microwave heating was used to improve aging effect of NiO films.
48
Behera, Binoda kumar. "Synthesis and Characterization of Nickel Doped Zirconia." Thesis, 2009. http://ethesis.nitrkl.ac.in/1019/1/binoda-project.pdf.
Full textAbstract:
The present work deals with effect of particle size, concentration of nickel, and calcination temperature on the enhancement of tetragonal zirconia nanopowders. Nanocrystalline tetragonal zirconia is commercially very significant material which finds extensive use as an anode material in SOFC, as a catalyst oxygen sensor and structural material.
In the present project work, nanocrystalline zirconia powders were prepared by co-precipitation technique. This technique is very helpful for the promotion of the stabilization of t-phase of ZrO2 at nano level at moderate temperature which is one of the primary objectives of this project. Here the main objective is to stabilize the t-ZrO2 through precipitation route using NH4OH.The concentration of nickel-salt plays an important role for the enhancement of stabilized tetragonal phase at moderate temperature. From XRD results it has been concluded that stabilization of t-ZrO2 was better for 20 mol% nickel-salt concentration as compared with 40 mol% Ni-salt at the same temperature.
49
DesEnfants, Robert E. "Synthesis and characterization of new rhodium/nickel-phosphorus and nickel-antimony carbonyl clusters." 1988. http://catalog.hathitrust.org/api/volumes/oclc/19334231.html.
Full textAbstract:
Thesis (Ph. D.)--University of Wisconsin--Madison, 1988.Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 251-252).
50
Mylnek, Peter D. "Synthesis, isolation, and characterization of variety of high nuclearity nickel-antimony, nickel-bismuth, and nickel-copper carbonyl clusters." 1996. http://catalog.hathitrust.org/api/volumes/oclc/36860318.html.
Full text