Dissertations / Theses on the topic 'Alloy layer'
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Taylor, Matthew Logan. "Hydrogen permeation of Alloy-22 considering the passive layer." abstract and full text PDF (free order & download UNR users only), 2007. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1446439.
Full textSOUTO, MARCELO BELMIRO GOMES DE. "CHARACTERIZATION OF THE OXIDIZED LAYER OF ALLOY ASTM F15 OBTAINED UNDER DIFFERENT SURFACE CONDITIONS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2015. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=25671@1.
Full textCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
A liga ASTM F15 é usada para o encapsulamento de componentes ou dispositivos eletrônicos em virtude de seu baixo coeficiente de expansão térmica que é similar à de vidros duros. Na construção de juntas vitro metálicas com características de hermeticidade a formação de uma camada de óxido na superfície metálica é necessária para que ocorra o molhamento adequado desta superfície pelo sealing glass. Neste trabalho foram utilizados dois tipos de superfícies, subdivididos em grupos, de modo a avaliar a sua influência na formação da camada oxidada. As superfícies foram oxidadas à temperatura de 800 graus C, em atmosfera ambiente, variando o tempo de oxidação em 5, 10, 20 e 40 minutos, seguido de resfriamento ao ar. As camadas de óxido foram caracterizadas quanto a sua morfologia e composição química, utilizando Microscopia Eletrônica de Varredura (MEV), Microscopia Ótica (MO), Difração de Raio X (DRX) e Espectroscopia de emissão e fótons de raio X (XPS) e Rugosimetria. As camadas de óxido foram avaliadas em função do ganho de massa superficial, espessura, composição química e rugosidade da superfície metálica. Os principais produtos de oxidação, nas condições estudadas foram Hematita (Fe2O3), Magnetita (Fe3O4) e Taenita (FeNi). Foi observado que e as condições superficiais de rugosidade não influenciaram o tipo de produtos de oxidação obtido, porém se obteve maiores ganhos de massa para as superfícies polidas mecanicamente.
The alloy ASTM F15 is used for the encapsulation of components or electronic devices because of its low coefficient of thermal expansion that is similar to hard glasses. In construction joints glass-to-metal tightness with characteristics forming an oxide layer on the metallic surface is required so that adequate wetting takes place at the surface of this sealing glass. This study looked at two types of surfaces, subdivided into groups in order to assess their influence on the oxide layer. One group was subjected to mechanical polishing and the other group subjected to chemical polishing. The surfaces were oxidized at a temperature of 800 degrees C in the ambient atmosphere by varying the oxidation time at 5, 10, 20 and 40 minutes, followed by cooling to air. As oxide layers were characterized for their morphology and chemical composition, using Scanning Electron Microscopy (SEM), Optic Microscopy, X-Ray Diffraction (XRD) and Emission spectroscopy and X-ray photons (XPS) and Rugosimeter.The oxide layer was evaluated in terms of surface mass, thickness, chemical composition and surface roughness of the metal surface. The main oxidation products under the conditions studied were Hematite (Fe2O3), Magnetite (Fe3O4) and Taenita (FeNi). It was observed that, surface roughness conditions did not influence the type of oxidation products obtained, but it had greater mass gains for the mechanically polished surfaces.
Zhao, Zhijun. "Role of surface active layers on localized breakdown of aluminum alloy 7075." Columbus, Ohio : Ohio State University, 2006. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1160670830.
Full textHazlehurst, Kevin Brian. "The adoption of laser melting technology for the manufacture of functionally graded cobalt chrome alloy femoral stems." Thesis, University of Wolverhampton, 2014. http://hdl.handle.net/2436/332114.
Full textDomfang, Ngnekou Julius-Noël. "Étude expérimentale de la tenue en fatigue de l’alliage AlSi10Mg élaboré par fusion laser de lit de poudre Influence of as-built surface and heat treatment on the fatigue resistance of Additively Layer Manufacturing (ALM) AlSi10Mg alloy Fatigue resistance of selectively laser melted aluminum alloy under T6 heat treatment Fatigue properties of AlSi10Mg produced by Additive Layer Manufacturing." Thesis, Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2019. http://www.theses.fr/2019ESMA0015.
Full textThis work shows the impact of defects and microstructure on the fatigue limit of AlSi10Mg produced by Additive Layer Manufacturing (ALM). Samples are produced according to three orientations with respect to the construction plate (0 °, 45 ° and 90 °); the studied surfaces are machined or left as-built (AB) in the gauge section. The specimens are studied with or without T6 heat treatment. The study surfaces are machined or as built. Some specimens are subjected to T6 heat treatment. Before any others study, the material is characterized in connection with the process parameters through several techniques (microscopes and 3D X-ray microtomography). Regarding the fatigue, the S-N curves are established before and after T6, mainly at R = -1 under uniaxial loading. For all the fatigue test specimens, fracture surfaces analysis shows that it is always a defect that cause fatigue failure. Thus, a criterion is applied to define these critical defects (type, size morphology and position) and the fatigue limit is analyzed through the Kitagawa type diagrams. The role of the building direction on the fatigue strength is studied, before and after T6 heat treatment, for both machined and as-built surfaces. For this purpose, a sketch based on the characteristic grain size is proposed to explain post-T6 orientation effects. The contribution of the precipitation structure is also studied; as well as the role of defects (type, size, morphology and position) on the fatigue limit at different microstructural states: before and after T6. In order to understand the surface fatigue damage mechanisms, the replica method is used on a polished specimen. In this context, a propagation law of natural cracks, that is to say due to a defect inherited from the process, is identified. It makes it possible to separate the initiation and propagation phases, thus feeding the discussions on the phenomena of priming in the presence of defects. In addition, some fatigue criteria are also discussed and the Defect Stress Gradient (DSG) approach is adapted to the studied material, by taking into account the size of the crystallographic grains. In the specific case of specimens with as-built useful sections, the role of the process of suppression of the building supports on the initiation of fatigue cracks is studied; the definition of the concept of defect size in the presence of roughness, at the scale of the surface undulation, is discussed. Knowing that initiation can occurs on a surface undulation or on an isolated defect (porosity or lack-of-fusion), an experimental method is proposed to analyze the competition between these factors. In a context of industrial development, the influence on the fatigue limit of the process parameters, related to the laser (scanning speed, power and hatching distance), or powder bed (chemical composition, particle size, bed thickness) is studied, in order to feed the discussions towards the process optimization regarding the fatigue strength
Li, Kai. "Origins and evolution of near-surface microstructures and their influence on the optical property of AA3104 aluminium alloy." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/origins-and-evolution-of-nearsurface-microstructures-and-their-influence-on-the-optical-property-of-aa3104-aluminium-alloy(69670a59-c416-40a1-920f-a246959791a4).html.
Full textЯременко, Денис Олегович. "Формування функціональних покриттів на сталі 40Х електроіскровим легуванням хромом та ніобієм." Bachelor's thesis, КПІ ім. Ігоря Сікорського, 2021. https://ela.kpi.ua/handle/123456789/43127.
Full textThe object of the study is the surface layers of 40X steel, obtained by electrospark doping with chromium and niobium anodes in air. The aim of the work is to establish the influence of EIL chromium and niobium sequences on the microstructure, phase composition and microhardness of 40X steel surface layers. Research methods - gravimetric, microstructural, microdyurometric and X-ray phase. The possibility of forming reinforced coatings (microhardness 9.5 GPa – 14.5 GPa and thickness 20 μm – 35 μm) by electrospark alloying of Cr and Nb steel 40X with different sequence of anode materials application is shown. The influence of chromium and niobium deposition during electrospark alloying of 40X steel on the surface microhardness, phase composition and microstructure of the modified layer was established. It was found that the alloyed layer has the highest microhardness (14.5 GPa) after the EIL of Nb steel, and the greatest thickness (35 μm) - with layered EIL in the Cr-Nb sequence. Practical significance: the results obtained in the work and the regularities of the formation of the structure and characteristics of the modified layers during electrospark alloying can be used to extend the service life of machine parts and mechanisms.
Kumar, Pawan. "Studies of wire-matrix interaction in some tungsten wire reinforced stainless steels." Thesis, University of Canterbury. Mechanical Engineering, 2013. http://hdl.handle.net/10092/8980.
Full textJagtap, Rohit. "The Effects of Ultrasonic Nano-crystal Surface Modification on Residual Stress, Microstructure and Fatigue Behavior of Low-Modulus Ti-35Nb-7Zr-5Ta-0.3O Alloy." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479823317088871.
Full textSeong, Jinwook. "Inhibition of Corrosion and Stress Corrosion Cracking of Sensitized AA5083." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429701294.
Full textLindsay, John Christopher. "Stress corrosion cracking and internal oxidation of alloy 600 in high temperature hydrogenated steam and water." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/stress-corrosion-cracking-and-internal-oxidation-of-alloy-600-in-high-temperature-hydrogenated-steam-and-water(1d6b037c-baf1-4397-a6c9-43835e7bb39a).html.
Full textRiegler, Andreas [Verfasser], and Laurens Wigbolt [Akademischer Betreuer] Molenkamp. "Ferromagnetic resonance study of the Half-Heusler alloy NiMnSb : The benefit of using NiMnSb as a ferromagnetic layer in pseudo-spin-valve based spin-torque oscillators / Andreas Riegler. Betreuer: Laurens Wigbolt Molenkamp." Würzburg : Universitätsbibliothek der Universität Würzburg, 2011. http://d-nb.info/101816328X/34.
Full textAyturk, Mahmut Engin. "Synthesis, annealing strategies and in-situ characterization of thermally stable composite thin Pd/Ag alloy membranes for hydrogen separation." Worcester, Mass. : Worcester Polytechnic Institute, 2007. http://www.wpi.edu/Pubs/ETD/Available/etd-042307-012951/.
Full textKeywords: composite Pd and Pd/Ag membranes, alloying, Pd/Ag barrier, intermetallic diffusion, bi-metal multi-layer BMML deposition, electroless plating kinetics, high temperature x-ray diffraction, aluminum hydroxide surface grading, porous sintered metal supports, hydrogen separation. Includes bibliographical references (leaves 279-296 ).
Sababi, Majid. "Nanocomposite films for corrosion protection." Doctoral thesis, KTH, Yt- och korrosionsvetenskap, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-132240.
Full textQC 20131024
Sexton, Cornelius Leo. "Rapid Alloy Scanning by laser cladding." Thesis, University of Liverpool, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.320605.
Full textCao, Pengcheng. "Characterization of Laser Deposited Alloy 718." Thesis, KTH, Materialvetenskap, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-182603.
Full textThomas, Jonova. "Microstructural Phase Evolution In Laser Deposited Compositionally Graded Titanium Chromium Alloys." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849610/.
Full textHUMBERT, PIERRE. "Etude de divers oxydes et interpretation des transitions auger de l'oxygene : caracterisation de couches oxydees de surface." Université Louis Pasteur (Strasbourg) (1971-2008), 1987. http://www.theses.fr/1987STR13205.
Full textLiang, Jing. "Direct laser fabrication of titanium alloy powders." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422998.
Full textEjaz, Muhammad. "Metal dusting of laser-treated alloy 800H." Thesis, University of Manchester, 2009. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.500503.
Full textFathi, Shida. "Kontroll av zinkskikt på monterat räckesmaterial." Thesis, KTH, Byggteknik och design, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-147182.
Full textControl of zinc coating on assembled railing materials made on site lacks a common methodology. Zinc coating should have a minimum thickness requirements according to the Swedish standard ISO 1461:2009, which is determined by the dimension of the steel thickness. Trafikverket expects that with help from this thesis it could limit the number of measurements on site, otherwise it will take too much time and labor resources, in case control of road and bridge railing systems are required from the customer. Probabilities and sampling in statistics helps us to limit the number of measurements of the protective devices that are made in the field. Using normal distribution, one arrive at the element of method that with reasonable effort gives a fair picture of the layer thickness of the assembled railing materials. Upon variation of the galvanizers on road barrier systems, each part is investigated separately by measuring zinc thickness of a galvanizers, checking the zinc coating thickness on them, take conclusions and later on investigate the next manufacturer. If a crash barrier is less than 30 pieces, the zinc coating thickness is measured at each facility by itself. For calculation of the zinc coating thickness on a mounted railing material one begins with 30 measurements and the use of the central limit theorem to approximate it to normal distribution and analyze the results. The final result of the thesis is an Excel program with input formulas. The Excel program is a tool for producing 95% confidence interval. Using this interval, one can make conclusions that if the zinc coating on a crash barrier fulfills the requirement or not and later on be able to come up with a result. If the requirement is in the interval or larger than the interval, the material is approved.
Merritt, Travis Robert. "Optoperforation of Intact Plant Cells, Spectral Characterization of Alloy Disorder in InAsP Alloy Disorder in InAsP Alloys, and Bimetallic Concentric Surfaces for Metal-Enhanced Fluorescence in Upconverting Nanocrystals." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/25148.
Full textPh. D.
Lee, Caroline Sunyong. "Surface layer formation on Pb/Sn alloys." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11603.
Full textSoib, Bin Selamat Mohmad. "Laser surface processing of Ti-6Al-4V alloy." Thesis, University of Strathclyde, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366777.
Full textOlakanmi, Eyitayo Olatunde. "Direct selective laser sintering of aluminium alloy powders." Thesis, University of Leeds, 2008. http://etheses.whiterose.ac.uk/1476/.
Full textZhang, Tao. "Laser surface hardening of AISI 1518 alloy steel." Thesis, Nelson Mandela Metropolitan University, 2010. http://hdl.handle.net/10948/723.
Full textLaurent, Michel P. "A continuum surface layer effect in polycrystalline aggregates." Thesis, This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-06082009-170819/.
Full textDe, Pauw Virginie. "Mécanismes de nitruration et d'oxydation du composé intermétallique Sm2 (Fe, Co)1#7 pour aimants permanents." Rouen, 1996. http://www.theses.fr/1996ROUES053.
Full textForsman, Tomas. "Laser welding of aluminium alloys /." Luleå, 2000. http://epubl.luth.se/1402-1544/2000/39/index.html.
Full textYoon, Jong Won. "Laser welding of aluminium alloys." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343303.
Full textHenke, M., and G. Gerlach. "A multi-layered variable stiffness device based on smart form closure actuators." Sage, 2016. https://tud.qucosa.de/id/qucosa%3A35622.
Full textDelaunay, François. "Etude de l'influence des éléments mineurs d'addition sur l'oxydation à haute température d'alliages base nickel." Rouen, 1997. http://www.theses.fr/1997ROUES029.
Full textВласенко, Олександр Володимирович, Александр Владимирович Власенко, and Oleksandr Volodymyrovych Vlasenko. "Електрофізичні та магніторезистивні властивості плівкових сплавів на основі Fe і Ge." Thesis, Сумський державний університет, 2021. https://essuir.sumdu.edu.ua/handle/123456789/85451.
Full textДиссертация посвящена исследованию электрофизических, магниторезистивных, магнитооптических свойств и эффекта Холла в пленочных системах на основе металла (Fe) и полупроводника (Ge) при фазообразовании. Изучение прoцесов фазообразования в двухкомпонентных пленочных материалах на основе Fe и Ge, сформированных методом послойной конденсации с последующей термообработкой в интервале температур 300–1070 К, позволили устаовить, что в пленочных сплавах, сформированных на основе отожжённых до 900–1070 К трехслойных пленок Fe (5–10 нм)/Ge (2–25 нм)/Fe (15–50 нм), в зависимости от соотношения концентраций атомов отдельных компонент образуются магнитные пленки германидов железа Fe2Ge, FeGe и FeGe2 со средними размерами кристаллитов 15–30 нм. Сравнение экспериментальных величин удельного сопротивления двухслойных плёночных систем Ge/Fe/П с расчетными на основе модели, в которой сохраняется индивидуальность отдельных слоёв, свидетельствует о том, что отличие между этими величинами можно объяснить эффектом образования экситонов Ванье–Мотта на основе 4 % электронов проводимости. Переход пленки германида железа из аморфного состояния в кристаллическое происходит при температурах Та→к = 560–590 К в зависимости от толщины образца. Формирования термостабильных (ТКС ~ 10–4 К–1) фаз FeGe и FeGe2 по всему объему образца приводит к росту величины МО от 0,02–0,04 % в неотожжённых системах до 0,30–0,44 % в отожженных до 900 К образцах. Наблюдается зависимость угла Керра от индукции магнитного поля в виде прямоугольной петли гистерезиса, что свидетельствует о реализации двух магнитных состояний и быстродействии чувствительных элементов устройств в магнитном поле. Получено, что постоянная Холла для двухслойных пленок на основе Fe и Ge имеет величину (6–11) .10-9 м3/Кл при росте индукции магнитного поля от 0 до 100 мТл. При увеличении интервала термообработки пленочных образцов до 570 К постоянная Холла уменьшается от 11·10−9 м3/Кл до 6·10−9 м3/Кл. Исследованы свойства тонких пленок углерода и нитрида углерода как защитных покрытий для пленочных чувствительных элементов. Показано, что плотность пленки CNx/Si (100) уменьшается при снижении температуры подложки и увеличении толщины образца, а максимальная концентрация атомов алмазоподобной структуры наблюдается в области подложки, а при толщине d ≥ 2 нм. Пленка однородная с постоянной плотностью, что свидетельствует о соответствии пленок CNx требованиям к покрытиям, которые могут быть использованы как защитные термостойкие слои для чувствительных элементов сенсорной электроники на основе силицидов и германидов металлов.
The thesis is devoted to systematic research of electrophysical, magnetoresistive, magneto – optical galvanomagnetic properties of film systems on the basis of metal (Fe) and semiconductor (Ge) in the conditions of phase formation. In film alloys formed based on annealed to 900–1070 K three-layer films Fe(5–10 nm)/Ge(2–25 nm)/Fe(15–50 nm), depending on the ratio of the concentrations of atoms of individual components, magnetic films are formed iron germanides Fe2Ge, FeGe and FeGe2 with average crystallite sizes of 15–30 nm. Comparison of resistivity of two-layer Ge/Fe/S (S-substrate) film systems with calculated ones based on the model, which preserves the individuality of individual layers, indicates that the difference between these values can be explained by the effect of Vanier-Mott excitons based on 4 % conduction electrons. The transition of the iron germanide film from the amorphous state to the crystalline state occurs at temperatures Tа→c = 560–590 K depending on the film thickness. The formation of thermostable (TRC ~ 10–4 K–1) phases of FeGe and FeGe2 over the entire volume of the sample leads to an increase in the value of MR from 0.02–0.04 % in non-annealed systems to 0.30–0.44 % in annealed to 900 K samples. It is established that in systems based on Fe and Ge films, the dependence of the angle Θ on the induction of the magnetic field in the form of a "stepped hysteresis loop" is observed, which indicates the realization of two magnetic states and the speed of sensitive elements of functional devices in a magnetic field. It has been experimentally established that the value of the Hall constant for two-layer films based on Fe and Ge (6–11)·10–9 m3/C with increasing magnetic field induction from 0 mT to 100 mT. When increasing the heat treatment interval of film samples to 570 K, the value of the Hall constant decreases from 11·10–9 m3/C to 6·10–9 m3/C. The properties of thin films of carbon and carbon nitride as protective coatings for film sensitive elements have been studied.
Sharman, Robert John. "Direct laser fabrication of a burn resistant titanium alloy." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.289751.
Full textBransden, Antony Stuart. "Laser surface alloying of aluminium alloys." Thesis, Coventry University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241106.
Full textOkon, Panton. "Laser conduction welding of aluminium alloys." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.400234.
Full textCalder, Neil J. "Laser welding of certain airframe alloys." Thesis, University of Liverpool, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366402.
Full textEbadan, Gracie E. "Laser welding of selected aerospace alloys." Thesis, Loughborough University, 1989. https://dspace.lboro.ac.uk/2134/7114.
Full textKuo, Je Ming, and 郭哲銘. "Investigating the Capping-layer effect on the PbAu alloy layer." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/69367197347650542123.
Full text國立清華大學
先進光源科技學位學程
103
The previous research shows that that a binary alloy composed of heavy atoms, Pb and Au, has large Rashba effect, yielding two cones at Γ ̅ and two giant Rashba splitting at M ̅. Experiments and first-principles calculations of the electronic structure indicated that such a Rashba effect may be produced only via a special buckling configuration induced by squeezing from the top Au capping layers and bottom Pb films. In this research, we demonstrated that with Bi as the capping layer on PbAu alloy, the Rashba effect is reproduced as well. This result means that Rashba-splitting band structure of PbAu alloy layer is caused by a capping layer on the top, which breaks the inversion symmetry and enhances the buckling height. We tried to deposit Bi onto PbAu alloy layer at Room temperature and low temperature, T = -130 ˚C, respectively and found that Rashba-splitting band structure only showed up at room temperature. It means that the atoms of capping layer must be at specific locations that are commensurate with Au atoms of alloy. In addition, we found that the binding energy of Rashba-splitting band structure shifted into higher binding energy and dispersion changed, indicating that we can use different kinds of atoms as the capping layer to tune the Rashba effect of the middle alloy.
CHEN, CHI-AN, and 陳麒安. "Nickel-phosphorus alloys deposited on magnesium alloy micro-arc oxidation layer using different catalysts." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/70561224320343144235.
Full text國防大學理工學院
化學工程碩士班
105
Magnesium-lithium alloy(LZ91) is currently the lightest of practical metal, its advantages are light (similar to plastic), higher strength, specific rigidity and better heat dissipation. Magnesium alloy is extremely to corrosion which seriously affecting its application in real life. In this study, Micro - arc oxidation of wet - type method was used to prepare a oxide film on magnesium alloy which improves corrosion resistance. The surface of the magnesium-lithium alloy treated by micro-arc oxidation was not beautiful. In corrosive environment, the outside layer is prone to failure. In order to solve this problem, the outer layer of oxide film to seal, which can prevent corrosion factor invasion. The oxide layer is without any activity, which needs to soak in catalytic active solution, therefore nickel ions can be catalyzed and evenly coated on the micro-arc oxidation of magnesium alloy to enhance the corrosion resistance and aesthetics. First discussion different voltage on corrosion resistance of micro-arc oxidation layer. After finding the best operating conditions, and then explore the characteristics of different catalysts and the effect of coating on the best conditions of micro - arc oxidation. Finally, the micro-arc magnesium oxide alloy with different catalyst was coated with nickel-phosphorus layer by electroless plating, and observe the corrosion resistance. In the experiment, the surface morphology and cross-sectional were observed by scanning electron microscopy(SEM). Electrochemical test linear polarization curve and salt spray to detect the corrosion resistance. The size of the catalyst particles is analyzed by a light scattering instrument. Catalyst stability is analyzed by stability analysis instrument. Contact angle analysis instrument analyzes the affinity between the catalyst and the micro-arc oxidation layer. The experimental results show that: the flat and dense oxide layer was prepared at a Bipolar pulses voltage of 400 V, which corrosion resistance is better. In the corrosion resistance test, the electrochemical test obtained corrosion current of 1.4 × 10-7 A / cm2, salt spray test can be passed 48 hours. Next, with different catalyst on the best micro-arc oxidation layer. The results show that the pH value of the 7 N type catalyst has a better performance. Its effective particle size is the smallest, the stability is better. The affinity with the micro-arc oxide layer is best and the corrosion resistance to the micro-arc oxide layer is less affected. Subsequent to electroless nickel-phosphorus layer, which can pass salt spray 24 hours . It is the best process conditions.
Chang, Chih-Wei, and 張智維. "A study of optical reflective layer with copper alloy." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/dqr7rs.
Full text國立臺北科技大學
製造科技研究所
93
In this study, copper alloy adding Ti-Zr and Al-Zr was the target and made the cupper alloy ingots by vacuum arc remelter (VAR). After rolling and heat treatment, the two-inch round target was cut by wire electrical discharge machining (WEDM). DC sputtering deposited cupper alloy thin films on silicon base materials and optical glasses to discuss the thin film microstructures、compositions、practical performances and optical characteristics. Metallographic methods and structure analysis were used to identify the reflectivity、surface morphology and structures of copper thin films. The results show that Cu-Ti-Zr alloy(CTZ1) thin films have 72% reflectivity with 650nm wave length. When more elements are added in copper alloys, the reflectivity and weatherability decrease. Higher Al element is good for corrosion resistance; Ti could restrain grain growth and enhance the heat resistance performance.
Chen, Kuan-Ting, and 陳冠廷. "Hole Mobility Calculation of Strained Silicon-based Alloy Inversion Layer." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19191830524761977918.
Full text國立中興大學
物理學系所
101
Advanced MOSFET device formed from novel Si-based materials, such as silicon-germanium (SiGe) alloys, are simple and low cost to manufacture. In this thesis we focus on hole mobility in the inversion layer of the MOSFETs using novel silicon-germanium alloy channel materials. The primary topic of this work is the theoretical calculation of hole mobility in the SiGe alloy PMOSFET inversion layer. Hole mobility in the SiGe alloy inversion layer is calculated using a k.p band structure method and the Kubo-Greenwood mobility formula. The model parameters used in the calculations are calibrated by matching the measured low-field mobility of Si and Ge. We study alloy-limited, phonon-limited, and total mobilities in the inversion layers of relaxed and biaxial strained SiGe on (100), (110), and (111) substrates, respectively.
Parng, Shaw-Hwa, and 龐紹華. "Injection Molding of Plastic Parts Covered with Superplastic Alloy Layer." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/69428580277467378923.
Full text國立臺灣大學
機械工程學研究所
89
A hybrid process combining the forming of superplastic Zn-22Al sheet with plastic injection molding is developed in this study. The product is a plastic part covered with a zinc-aluminum layer, providing a continuous metal enclosure for shielding against EMI. The process is first investigated with aid of moldability study and process observation. Plates with features such as rib or boss are molded. The moldings of housing cases with different degrees of preforms for improving moldability and a variety of schemes for reducing warpage are also investigated. In the process observation with aid of short-shots, it is found that almost 80% of the sheet deformation for forming ribs occurs during the final filling stage. For defining moldability, melt temperature and injection pressure are found to be the most critical processing parameters after performing experiments with Taguchi method. The moldability is then defined based on the molding area on the plane of these two parameters. Increasing sheet thickness, decreasing the rib depth and decreasing the flow length enlarge the molding areas and improve moldability. The biggest effective strain and smallest residual thickness are found to be in the center of the boss. For successfully molding of Zn-22Al covered plastic housing case, an appropriate preform depth accompanied with proper melt filling channel is necessary for moldability. Excess preform depth of the Zn-22Al sheet would cause fracture of the sheet on the corners, and induce big pressure pulling down the sheet when melt flowing in the thick channel. For reducing warpage of molded plastic housing cases with Zn-22Al sheet, Zn-22Al sheet pre-rolled with ABS layer on the surface before injection molding is found to be effective in reducing warpage. With the total thickness of sheet-plastic composite fixed, the optimum thickness ratio for best bending rigidity and minimum weight are also derived in this study. The simulations of process are also carried out with finite element softwares of MOLDFLOW for melt filling and ABAQUS for sheet forming. The distributions of pressure and melt temperature on various sites are obtained from the simulated results using MOLDFLOW. These data is then used as loading conditions to simulate the deformation process of the Zn-22Al sheet using ABAQUS during melt filling of the cavity for plate with rib. The simulated sheet thickness distribution in the rib sections and strain rate during the filling process are compared with the measured data.
Gu, Shao-Ming, and 谷紹民. "Synthesis of Large-Area Graphite Layer from Fe-Ni-Cu Alloy." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/x369dh.
Full text國立臺北科技大學
材料科學與工程研究所
99
This research was using the liquid phase of Fe-Ni-Cu alloy to dissolve graphite powder; precipitate then synthesis to a large-area graphite layer on the surface of the alloy. The research used a sintering vacuum at 1350 ℃ for up to 5 hours. To observe the interaction of Fe-Ni-Cu with carbon at different isothermal times, using samples of 1.5C-Fe58.45Ni25.05Cu15 (wt%), lead to the investigation of the graphite layer growth mechanism. According to this research, copper had played an important role of controlling the segregation of carbon. The growth rate and nucleation had been elevated dramatically due to the existence of copper at a small amount. The content distribution range (carbon content 1.5 wt% to 2.5 wt%, and the copper content 1.0 wt% to 30 wt%) of carbon and copper could lead to the ideal result expected which is the large-area graphite layer. The outcome would be at its best quality at this specific allocation, which was carbon content 1.5 wt% and copper content at 15 wt%. We could find graphene signal through Raman analysis at 1.5 wt% carbon and 1 wt% copper. Due to the change of isothermal times, the mechanism of graphite layer growth could be deduced. The variation of growth steps could influence graphite layer’s wrinkle level and its appearance. Under this content of carbon and copper (1.5C-Fe58.45Ni25.05Cu15), which etched by nitric acid, could separate into a large-area graphite layer from Fe-Ni-Cu alloy. The graphite layer sample would be a beneficial usage to future development.
CHENG, CHEN-YI, and 鄭駿毅. "The Study of Corrosion Properties of MAO Layer on Magnesium Alloy." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/02362332454877411327.
Full text國防大學理工學院
化學工程碩士班
104
Magnesium and its alloys as the lightest structural material, has some excellent properties such as low density, high strength, excellent casting and workability, etc. The application of magnesium alloys has been widely used in industry field. However, magnesium alloys have a poor corrosion resistance and limit their application. Many surface treatment techniques have been developed to protect the magnesium alloys from corrosion, including chemical treatment, oxidation, organic coatings, conversion coating, anodizing and metal coating. In this study, magnesium alloy (AZ31) was used as a substrate, the MAO technique was used to produce an oxidation layer having a high corrosion resistance and to improve the corrosion resistance of magnesium alloy. In first, the effect of different waveforms (DC, unipolar pulses, bipolar pulse) and voltages on the corrosion resistance of AZ31 that prepared by MAO process and then coated a nickel phosphorus layer are studied. The surface morphology and the cross-sectional of coatings were analyzed by SEM, the phases analysis were carried out by XRD, the corrosion behavior of coatings were measured by electrochemical linear polarization curve test and salt spray test. Finally, the adhesion between nickel-phosphorus layer and MAO layer were measured by a pull adhesion test, to find out the relationship between the adhesion and corrosion resistance. The experimental results show that the main components of micro-arc oxidation layers prepared by different parameters included MgO, Mg2SiO4, MgF2 and Mg. The different operated parameters of MAO process played a dominate role on the corrosion resistance, pore size and porosity of MAO layer. When the bipolar pulse waveform voltage is at 400 V, the MAO film has the best corrosion resistance due to its maximum pore size and the lowest porosity, and the salt spray test can through 144 hours. Then, the MAO films was coated a nickel-phosphorus layer by chemical plating and the corrosion resistance of MAO-nickel-phosphorus layer was studied. The results show that the MAO films formed at a bipolar pulse waveform voltage of 400 V and coated nickel-phosphorus layer has the best corrosion resistance that can resist corrosion on salt spray test for 96 hours. Therefore, the optimal parameters on preparing a MAO film was the bipolar pulse waveform and the operated voltage was at 400 V; moreover, it can obtain best adhesion between MAO layer and nickel-phosphorus layer, and has the best corrosion resistance.
Fan, Chao-Hsiung, and 范朝雄. "Study on the Oxidation Wear Behavior of Laser Clad Layer of Pre-placed Nickel-based Alloy Powder." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/46056716634181532285.
Full text國立中正大學
機械系
90
Abstract In this work, the Nickel-based alloy powder Metco 15E and Colmonoy 88 were mixed with binder and were pre-placed on the surface of mild steel substrate and then cladding of these alloy by using Nd-YAG laser was carried out. Study was carried out to evaluate the wear characteristics of clad layers before and after oxidation at elevated temperature. In order to probe into the characteristics of oxidation layer, compositions of oxides were analyzed by scanning electron microscopy (SEM) and energy dispersive X-Ray Spectrometry (EDS). Besides, the influence of the oxides on high temperature wear test results was also an important issue which was analyzed using EDS. Wear traces were investigated using SEM to identify the possible wear mechanisms. The results of the high temperature oxidation show that the oxide layer consists mainly of the Cr and Si oxides. The dilution of pre-placed laser clad layer with the substrate was higher than that achieved by synchronic powder feeding. It revealed severe oxidation on the pre-placed laser clad layer. High temperature wear test results show that the wear resistance of oxidized clad layer was superior to that of the as-clad layer. This result implies that oxidized layer is advantageous for high temperature wear resistance. Moreover, the wear resistance was inferior under lower wear speed. Surface analysis results shows that the dominant wear mechanisms were adhesive mechanism and detach mechanism. In general, the wear resistance of Colmonoy 88 was better than that of Metco 15E.
Wu, CH, and 吳忠興. "Al2O3/ZrO2 Double Layer on Co-Cr-Mo Alloy by Electrolytic Deposition." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/45966088070308371001.
Full text國立中興大學
材料工程學研究所
89
Double layers of Al2O3/ ZrO2 composite films were Co-Cr-Mo alloy in 0.003125M ZrO(NO3)2 and then in 0.01M Al(NO3)3 aqueous solution. Various compositions of composite coating were obtained by controlling several electrochemical parameters, such as solution concentration, applied potential, deposition time and different sintering conditions. Its characterization was conducted by using potentiostat, SEM/EDS, XRD, immersion test, wear test and scratch test. The alumina coating has a better quality in resistance corrosion and wear, but the zirconia coating is more close to metal substrate than alumina coating. Depend on this, first electrolytic deposition of zirconia then deposition of alumina on Co-Cr-Mo alloy. Controlling aqueous concentration, electrolytic deposition of potential and deposition time. To expect obtain better property ceramic thin flim. Cycle polarization tests in Hank,s solution indicate that the Al2O3/ZrO2 coating has a better quality in resistance corrosion than the single Al2O3 or ZrO2 ceramic thin film. The scratch test of Al2O3/ZrO2 coating, in the vestige end part of alumina and zirconia still remains on the Co-Cr-Mo alloy from SEM/EDS analysis. Al2O3/ZrO2 ceramic thin film can to protect Co-Cr-Mo alloy from immersion test. From wear-corrosion behaviour the wear test influence the substrate serious than Al2O3/ZrO2 ceramic thin film deposition on substrate. In the corrosion potential and dissolution current of unimplanted Co-Cr-Mo and Al2O3/ZrO2 ceramic thin film deposition on substrate. Al2O3/ZrO2 ceramic thin film deposition on substrate unrestricted. From all kinds of analysis to show that electrolytic deposition of Al2O3/ZrO2 ceramic thin film on Co-Cr-Mo alloy have good properties.
Tsai, Yi-Lin, and 蔡易霖. "Synthesis of Large-Area Graphene Layer from Fe-Ni-Cu-Mn Alloy." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/kw7kq9.
Full text國立臺北科技大學
材料科學與工程研究所
100
This research used the liquid phase of Fe-Ni-Cu-Mn alloy to dissolve graphite powder; precipitate then synthesis to a large-area graphite layer on the surface of the alloy. We made use of a smelting vacuum furnace at 1350 ℃ for up to 5 hours to obtain the various samples in different alloy power ratios. And, we found some formulas which can produce a large-area graphene. According to our observation, A proper dendrite structure collocate a fine graphite wrinkle which will help the forming of partition phenomenon between graphite layers. In other words, the van der Waals bond might be vanished between graphite layers, so the graphite disassemble into the folded graphenes. According to this research, copper plays an important role of controlling the segregation of carbon, and manganese enhances its ability. The partition phenomenon then take place dramatically in some alloy formulas. Finally, we separate its folded graphene film from the alloy surface by means of etching. The maximal area of graphene is about 2500μm2 We also observed the surface of the graphene to check the relation of appearance and graphene area by a simple location skill. Therefore, we can understand the principle to form the large area graphene layer by liquid phase metals, so as to be the foundation of application of high quality graphene layers.
Hsieh, Chih-Hung, and 謝志宏. "Study on Corrosion Resistance of Copper-Zinc Alloy by Multi-layer Coating." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/afw266.
Full text國立臺北科技大學
資源工程研究所
106
Copper-zinc alloy is the most important material in terms of electronic connectors. Most of the connector industries apply a protective layer by electroplating on the surface of alloy material. Traditional protective layer consists of nickel-plating on the first layer and tin-plating on the surface layer. This research puts major emphasis on multi-layered plating of the alloy material. Design of protective layer is copper-plating on the first layer, nickel-plating on the second layer, and tin-plating on the appearance. Under the requirement of the steady production quantity and maintaining the same operating time of the process and output voltage of the electroplated metal, first of all, we conducted the electroplating process with an additional copper electroplating procedure in the continuous electroplating process. Second, after finishing the electroplating, we observe the crystal structure of the surface of electroplated material by the electron microscope. Finally, we tested the corrosion resistance of multi-layered plating process with salt spray test. The proposed experimental procedure is as follows. First of all, on a basis of the fixed electroplating time and fixed output voltage of the electroplated metal, we apply electroplating by an additional copper electroplating procedure of the continuous electroplating process. Second, under the requirement of electroplating on the alloy material with the same total film thickness following the original specification, we do not change the film thickness on the surface tin-plating layer, but decrease the film thickness of nickel-plating layer of the original alloy material and add a first copper-plating layer of the original alloy. It is able to achieve the same total thickness as the original double-layered plating does. Finally, we observe the multi-layered and double-layered plated samples after they are under salt spray trial. The analysis indicates that multi-layered plating performs better than double-layered in terms of the corrosion resistance.
Hsiao, Yo-Cheng, and 蕭祐晟. "Preparation of high emissivity layer on titanium alloy by micro-arc oxidation process." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/01333922336244322829.
Full text中華大學
機械工程學系
105
There are various high emissivity heating pads in the market, however the medical performance of some heating pads is still open to discussion. The traditional infrared heating sources are mostly from electric wire and carbon fiber based composites. Unfortunately, they exist serious energy loss problems during energy transfer which needs to be improved. This study aims to prepare a high emissivity layer on titanium metal by micro arc oxidation process. The energy loss problems can be significantly improved because emission layer and substrate are integrated into one body. Other advantages of titanium metal to be applied in medical devices includes excellent biocompactivity and safety. The micro arc oxidation technology.is mature for surface treatment of titanium alloy and biocompactivity. However, related studies regarding MAO treatment for ultrathin titanium alloy and effects of process parameters on emissivity of oxide layer are still lacking. In this study, a rough and porous titanium oxide coating) will be applied on a 0.1and 0.07 -mm thick titanium metal sheet by using a microarc oxidation process, The parameter effects of the microarc oxidation process including the cathode voltage and process duration on the structure, surface morphologies, and thickness of the oxide layer were investigated. The emissivity of the oxide layer was measured by infrared thermal image analyzer. The highest emissivity of titanium oxide layer can achieve 0.96.