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1
Wang, Haoran. "Preparation of Titanium Oxide/Epoxy Hybrid Anticorrossive Coating." University of Akron / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=akron1480326524997686.
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Tyurin, Yu, O. Ivanov, O. Kolisnichenko, M. Kovaleva, I. Duda, O. Maradudina, and Y. Trusova. "Properties of nanostructured composite titanium coating on aluminium surface." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/20488.
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Bastien, Samuel. "Selective chemical stripping of titanium aluminum nitride coating from titanium substrate using hydrogen peroxide and potassium oxalate." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110474.
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Titanium Aluminum Nitride (TiAlN) is an important industrial coating that improves hardness and corrosion resistance. The objective of the present work is to develop chemical methods which selectively remove TiAlN coatings deposited on Titanium substrates. The selected stripping solution consists of hydrogen perox¬ide (H2O2) and potassium oxalate (K2C2O4). Coupons of Ti-6-4 coated with a notional 10 micron thick coating of TiAlN were exposed to a stripping solution at varying temperature and compositions. Overall, it was found that increasing the temperature of reaction or the concentration of reactants led to an increase in stripping rate of the coating and substrate. The selectivity also increased with an increase in tempera¬ture or potassium oxalate concentration, but decreased with an increase in hydrogen peroxide concentration. The highest stripping rate that was obtained for the coating was of 39 µm/hr at a tempe¬rature of 75oC, a concentration of hydrogen peroxide of 5.9 mol/L and a potassium oxalate concentra¬tion of 0.226 mol/L. At the same conditions, uncoated samples were found to be stripped at a rate of 6.6 µm/hr. The best selectivity that was obtained was of 6.8, at a potassium oxalate concentra¬tion of 0.226 mol/L, a hydrogen peroxide concentration of 4.4 mol/L and a 75oC temperature. It was also found that the ratio of Ti:Al in the coating had a major effect on its chemical resistance to H2O2 and K2C2O4 mixtures.Titanium Aluminum Nitride (TiAlN) est un revêtement industriel important puisqu'il améliore la dureté et la résistance à la corrosion. L'objectif de ce travail est de développer des techniques chimiques qui enlèvent de façon sé¬lective des revêtements de TiAlN déposés sur des substrats de Titane. La solution chimique sélection¬née consiste de peroxyde d'hydrogène (H2O2) et d'oxalate de potassium (K2C2O4). Des échantillons de Ti-6-4 couverts d'une couche de TiAlN d'une épaisseur notionnelle de 10 micromètres ont été exposés à plusieurs solutions chimiques avec des températures et concentrations variées. De façon générale, nous avons trouvé que si on augmentait la température de la réaction ou la concentration des réactants, cela faisait augmenter les vitesses de dégradation du revêtement et du substrat. La sélectivité augmentait aussi avec une hausse de la température ou de la concentration d'oxalate de potassium, mais diminuait avec une hausse de la concentration de peroxyde d'hydrogène. La plus haute vitesse de dissolution du revêtement qui a été obtenue était de 39 µm/hr à une température de 75oC, une concentration de peroxyde d'hydrogène de 5.9 mol/L et une concentration d'oxalate de potassium de 0.226 mol/L. À des conditions similaires, le substrat se dissolvait à une vitesse de 6.6 µm/hr. La meilleure sélectivité obtenue était de 6.8, à une concentration d'oxalate de potassium de 0.226 mol/L, une concentration de peroxyde d'hydrogène de 4.4 mol/L et une température de 75oC. Nous avons aussi trouvé que le ratio de Ti:Al dans le revêtement a un impact majeur sur sa résistance chimique aux solutions de H2O2 et de K2C2O4.
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Wang, Xihong. "Wear behavior of PVD titanium nitride-coated tool steels /." Full text open access at:, 1989. http://content.ohsu.edu/u?/etd,237.
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Gromov, V. E., N. A. Soskova, S. V. Raikov, E. A. Budovskikh, A. V. Ionina, I. V. Lushina, and S. V. Konovalov. "Nanosize Structure Phase States of Ti Surface Layer Formed During Electroexplosive Carboborating." Thesis, Сумський державний університет, 2012. http://essuir.sumdu.edu.ua/handle/123456789/34804.
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The electroexplosive carboborating leads to a significant (up to 12 times) increase in microhardness of the titanium
irradiated surface. It is established that the thickness of strengthened surface layer reaches ~ 125 μm.
The formation of nanosize structure-phase states in Ti surface layers during electroexplosive carboborating
was carried out by methods of scanning and transmission diffraction electron microscopy.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/34804
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GONCALVES, ANDRE. "Obtencao e caracterizacao de revestimentos compostos de multicamadas TiOsub(2)/TiN." reponame:Repositório Institucional do IPEN, 2010. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9572.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Lee, Seungchan. "Size modification and coating of titanium dioxide using a premixed hydrogen/air flame." College Park, Md. : University of Maryland, 2006. http://hdl.handle.net/1903/3937.
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Thesis (M.S.) -- University of Maryland, College Park, 2006.Thesis research directed by: Dept. of Chemistry and Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Duddukuri, Ramesh. "SYNTHESIZING AND CHARACTERIZATION OF TITANIUM DIBORIDE FOR COMPOSITE BIPOLAR PLATES IN PEM FUEL CELL." OpenSIUC, 2012. https://opensiuc.lib.siu.edu/theses/862.
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This research deals with the synthesis and characterization of titanium diboride (TiB2) from novel carbon coated precursors. This work provides information on using different boron sources and their effect on the resulting powders of TiB2.The process has two steps in which the oxide powders were first coated with carbon by cracking of a hydrocarbon gas, propylene (C3H6) and then, mixed with boron carbide and boric acid powders in a stoichiometric ratio. These precursors were treated at temperatures in the range of 1200-1400° C for 2 h in flowing Argon atmosphere to synthesize TiB2.The process utilizes a carbothermic reduction reaction of novel carbon coated precursor that has potential of producing high-quality powders (sub-micrometer and high purity). Single phase TiB2 powders produced, were compared with commercially available titanium diboride using X-ray diffraction and Transmission electron microscopy obtained from boron carbide and boric acid containing carbon coated precursor.
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Domenici, V., S. Dolci, G. Pampaloni, and Z. Jaglicic. "New Ultra Small Iron-Oxide Nanoparticles with Titanium-Carbamate Coating: Preparation and Magnetic Properties." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35456.
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This work deals with the preparation and chemical characterization of new Ultra-Small Iron-Oxide Superparamagnetic
Nanoparticles (USPIONs) functionalized with Titanium-carbamate. The synthesis was performed
starting from oleate-coated and 2-pyrrolidone-coated USPIONs having a maghemite ( -Fe2O3) and
magnetite (Fe3O4) crystalline core, respectively. Zero-field-cooled (ZFC) and field-cooled (FC) magnetic susceptibility
curves as well as the magnetization behavior as a function of temperature are reported and discussed
in view of the superparamagnetic properties and coating effect of these new magnetic nanoparticles.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35456
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Kar, Archana. "Hydroxyapatite deposition onto nanoporous TiO2 and assessment of bone cell growth and proliferation." 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:1447622.
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Nelson, Kimberly Lynn. "Enhanced performance and functionality of titanium dioxide papermaking pigments with controlled morphology and surface coating." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/24645.
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Thesis (Ph.D.)--Chemical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Yulin Deng; Committee Member: Arthur Ragauskas; Committee Member: Jeff Empie; Committee Member: Jeffery Hsieh; Committee Member: Preet Singh
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Besu, Nicole. "Silver doped hydroxyapatite coating on titanium surfaces and its effect on early bone response and osseointegration." View the abstract Download the full-text PDF version (on campus access only), 2007. http://etd.utmem.edu/ABSTRACTS/2007-004-Besu-index.html.
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Thesis (M.S.)--University of Tennessee Health Science Center, 2007.Title from title page screen (viewed October 10, 2007). Research advisor: Joo L. Ong, Ph.D. Document formatted into pages (vi, 22 p. : ill.) Vita. Abstract. Includes bibliographical references (p. 23-32).
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Gudima, Alexandru [Verfasser], and Julia [Akademischer Betreuer] Kzhyshkowska. "Analysis of reactions of macrophages to titanium and biodegradable coating materials / Alexandru Gudima ; Betreuer: Julia Kzhyshkowska." Heidelberg : Universitätsbibliothek Heidelberg, 2018. http://d-nb.info/1177252449/34.
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Jankus, Daniel James. "Antimicrobial Properties of Graphite and Coal-Derived Graphene Oxides as an Advanced Coating for Titanium Implants." Thesis, Virginia Tech, 2021. http://hdl.handle.net/10919/103151.
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Prosthetic joint infection (PJI) poses a significant risk to implanted patients, requiring multiple surgeries with high rates of reinfection. The primary cause of such infections is otherwise innocuous bacterial species present on the skin that have survived sterilization protocols. Antibiotic drugs have significantly reduced efficacy due to the lack of vasculature in the newly implanted site, allowing microbes to form biofilms with even greater resistance. Graphene oxide (GO) is known to have good biocompatibility while providing drugless antimicrobial properties. The focus of this study is on the development and characterization of a robust coating for titanium alloy implants to promote bone regeneration while inhibiting microbial biofilm adhesion to the implant surface. The novelty of this study is the use of proprietary coal-derived graphene oxide (c-GO) in a biomedical application. c-GO has been demonstrated to have a greater number of functional oxygen groups to promote cell adhesion, while also maintaining thinner layers than possible with graphite exfoliation methods. As an alternative to powerful antimicrobial drugs, it was hypothesized that an advanced coating of graphene-oxide would provide a defensive, passively antimicrobial layer to a titanium implant. While GO is typically quite expensive, the newly developed process provides an economical and environmentally friendly method of producing GO from coal (c-GO). The result is a coating that is inexpensive and capable of halving the biofilm formation of MRSA on titanium-alloy surgical screws in addition to providing improved bone cell adhesion and hard tissue compatibility.Master of Science
Any time a patient receives implantation surgery, there is a chance of microbes entering the body. These are typically naturally occurring skin flora, harmless but opportunistic. On the surface of implants within the body, these bacteria can form colonies called biofilms, leading to severe and potentially deadly infections, called prosthetic joint infection (PJI). PJI often requires multiple surgeries to remedy, but rates of reinfection are relatively high. As with any surgery, patients are given antibiotic drugs, but implants to not receive blood flow as the body normally would, reducing the effectiveness of antibiotics. Once biofilms are formed, the bacteria become even hardier and resistant even to powerful antibiotics. Graphene oxide (GO) is a carbon material known to have good biocompatibility (i.e., non-toxic) while providing antimicrobial properties. The focus of this study is on the development and characterization of a robust coating for titanium alloy implants to promote bone healing while reducing microbial biofilm colonization on the implant's surface. The novelty of this study is the use of proprietary coal-derived graphene oxide (c-GO) in a biomedical application. c-GO has been demonstrated to have a different chemical makeup than graphite-derived GO, which may improve its efficacy as an antimicrobial coating. As an alternative to powerful antimicrobial drugs, it was hypothesized that a coating of graphene-oxide would provide a defensive, passively antimicrobial layer to a titanium implant. While GO is typically quite expensive, the newly developed one-pot process provides an economical and environmentally friendly method of producing GO from coal (c-GO). The result is a coating that is inexpensive and capable of halving the biofilm formation of MRSA on titanium-alloy surgical screws in addition to providing improved bone cell adhesion and hard tissue compatibility.
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GUERREIRO, SERGIO S. "Estudo e caracterizacao de filmes finos de nitreto de titanio obtidos por evaporacao a arco catodico de deposicao a vacuo." reponame:Repositório Institucional do IPEN, 1994. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10377.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Muralidas, Pooja. "Thermo-gravimetric Analysis of Corrosion Kinetics of Ti and Zr Coated P91 Steel." OpenSIUC, 2016. https://opensiuc.lib.siu.edu/theses/2057.
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In recent decade growing concerns of CO2 emissions from power plants have increased, which led to development of technologies like oxy-fuel combustion process. P91 steel is profoundly used in power plants, but oxy fuel combustion exacerbates corrosion due to recycling of flue gas. This paper studied the kinetics of the corrosion rate on the boiler tubes and furnace and help achieve a corrosion resistant coating over it. Refractory metal diffusion coating is created and tested at high temperature in corrosive atmosphere. This was done by forming Ti and Zr diffusion coating on P91 steel using pack cementation. Coating thickness of 12 and 20 µm were obtained for Ti and Zr respectively. These samples were tested in thermo-gravimetric system by heating at 950˚C for 24 hours in 5% oxygen in Helium gas. Heating in an oxidizing environment lead to exfoliation corrosion on uncoated P91 steel. TGA procedure confirmed less mass change of Ti and Zr coated samples, than that of uncoated P91 steel sample. SEM and depth profiling confirms oxygen penetration is 2.7mm in uncoated P91 steel sample, whereas the Ti and Zr Coated samples oxygen penetration is just 16 and 56 µm respectively.
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Belov, D. S., I. V. Blinkov, A. O. Volkhonskiy, and J. Michalski. "Discrete Modified Nanostructural Wearproof Coatings TiN-Cu." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35311.
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Discrete modified nanostructural wearproof coatings Ti-N-Cu with crystallites size from 100 to 20 nanometers formed with ion-plasma vacuum-arc method. Copper amount in the received coatings made from 0 to 20 at. %, their hardness have considerably increased up to about 40-45 hPa in comparison with 20-22 hPa for Ti-N coverings. In this work, processes of structure and phase formation of Ti-N-Cu system coatings in a wide interval of copper concentration are investigated.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35311
18
Karlsson, Marjam. "Nano-porous Alumina, a Potential Bone Implant Coating." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4452.
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Nuño, Manuel. "Photocatalytic coatings in the built environment." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.687320.
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The photocatalytic properties of titanium dioxide have been widely studied over recent decades since the discovery in 1972 of water photolysis by TiO2 electrodes. There are a number of different TiO2 polymorphs. Rutile and anatase are the most studied due to their chemo-physical properties. Under ultraviolet light, TiO2 is able to absorb photons, creating a charge separation on the surface, an electron and a positive “hole”. This electron-hole pair then reacts with water and oxygen, generating radicals, very unstable and reactive species which show great potential for neutralisation of pollutants. In the introduction the state of art of photocatalysis; chemo-physical principles, applications and current analysis are described. A number of protocols to test photoactivity are discussed with particular emphasis on the importance of gas phase reactions. The development of a novel system to study gas phase reactions by mass spectrometry was explored, detailing the conditions and parameters that were optimised. This instrument was used to analyse photocatalytic properties of TiO2 powders and photocatalytic coatings under different UV light conditions. The results showed how TiO2 in the form of anatase and rutile removed nitrogen and carbon dioxide under different UV light sources, with anatase being more effective. A comprehensive study of several commercially available TiO2 powders and coatings was performed to identify the differences between photocatalytic properties, using electron microscopy, Raman and UV-vis diffusive spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. An important question that was answered in this thesis is whether the physical properties of nanoparticles or their electronic properties are critical for their photocatalytic behaviour. Results for anatase powders of different particle size and surface area showed how the positioning of their electronic band gap with the wavelength of the UV light source was fundamental for an effective photocatalyic process. In order to improve the photocatalytic process, “self-doping” TiO2 was investigated. Different reduction temperatures were studied to generate the best ratio of Ti3+-Ti4+ that stabilised the charge distribution process to maximize the electron-hole pairs generated per photon in the gas phase. From a wide range of reduction temperatures, titanium sub-oxime reduced at 400 oC showed the best performance in removing carbon dioxide. In the application of TiO2 for the built environment, the best commercially available TiO2 powder, anatase P25 was applied with two different techniques. Electrophoretic deposition has the potential to scale up the process for prefabricated panels in construction. Solvent, iv deposition time, voltage and substrate were optimised. The resulting photoactivity of the coatings was evaluated showing a higher efficiency than a compressed pellet of anatase P25. The final part of the thesis was dedicated to the formulation and application of a photocatalytic enhanced lime based coatings for the built heritage. The use of calcium hydroxide dispersions is widely used in the conservation and restoration community, reinforcing limestone when it carbonates. Anatase P25, was added to improve the performance in polluted atmospheres, acting as a sacrificial barrier. Results showed that by adding anatase to the formulation, calcium hydroxide reacted preferentially with sulphur dioxide over carbon dioxide. The final product in the formulation with anatase was calcium sulphate, whereas the final product for the calcium hydroxide formulation was calcium sulphite. Finally, a general discussion of the results is presented and the conclusions of this research are drawn. Recommendations for further work are presented in the last chapter.
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Lewis, Oliver David. "A study of the influence of nanofiller additives on the performance of waterbourne primer coatings." Thesis, Loughborough University, 2008. https://dspace.lboro.ac.uk/2134/4646.
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Organic coatings are frequently applied to metals, often in circumstances where there is a need to protect the substrate from corrosion or to improve the aesthetic quality of a product. Increasingly, coatings are also expected to provide additional functionality, such as anti-bacterial properties. Concurrent with the need to satisfy ever more demanding specifications, coating formulators are being obliged to comply with stringent environmental legislation. A research area which may benefit the development of coating formulations is that of nanocomposite synthesis, in which the composite additives have at least one dimension in the nanometre size range. The current research has sought to modify a waterborne organic coating primer with two types of nano-sized additives: layered clays and titanium dioxide nanoparticles. Dispersion of the particles at loadings up to 5% w/w was achieved by ball milling and the modified coatings were subjected to numerous tests to ascertain the effect of the additives. Titanium dioxide was found to improve the tribological properties and corrosion resistance of the coatings, while the addition of magnesium aluminium hydroxycarbonate (hydrotalcite) layered clay had a deleterious effect. Some coatings exhibited a cracked morphology, although no correlation between particle loading and the presence of cracks could be determined. A preliminary investigation into substrate preparation was also conducted. This ensured that the degree of cleanliness of the hot-dip galvanized substrates was both satisfactory and consistent.
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Hammond, Derek. "An investigation of the impact of selected cooling strategies on milling of difficult-to-cut materials with an emphasis on titanium alloys and hardened steel." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/80372.
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Thesis (MScEng)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The aerospace- and automotive industries have an urgency to save space and reduce weight, as well as a need to increase fuel efficiency and reduce emissions. This has led to the use of lightweight structural materials, such as Ti6A14V alloy, which is the most widely used titanium alloy in the aerospace industry. This alloy has an exceptional strength-to-density ratio. The work also covers studies on tool steel 40CrMnMo7 that is used in applications in the tooling-, aerospace and automotive industry. In the quest for improved performance new alternative methods of efficiently machining these materials are investigated. One of the important criteria during machining of these materials is their machinability. This study discusses current research in high performance machining strategies and techniques for advanced materials such as Ti6Al4V and 40CrMnMo7. The properties that make these materials advantageous for the use in the aerospace- and automotive industry also make them difficult to cut. The widespread application of Ti6Al4V in the aerospace industry has encouraged investigations into cooling strategies or -techniques to maintain and improve tool life. Ti6Al4V has a low thermal conductivity causing the heat generated during machining to accumulate on the cutting edge of the tool. During various experiments the application of external compressed air blow cooling (dry cutting), flood cooling, high pressure through spindle cooling (HPTSC) and modifications thereof were investigated. The research project also evaluated the performance of a coating (TiAlN) and various coating treatments. The objectives of the HPTSC modifications were to improve the coolant stream impingement on the tool surface, effectively compressing the thermal barrier, and to reduce the chip-tool contact area. This would lead to a decrease in tool heating and wear. The modified techniques failed to increase tool life but showed signs of increased heat removal capability under the given conditions. It was observed that air blow cooling (dry cutting) delivered the best results when considering cutting materials, coating, coating treatment and cooling strategies or –techniques throughout the experiments conducted.
AFRIKAANSE OPSOMMING: Die Ruimte-en motor-industrie het 'n dringendheid om ruimte te bespaar en gewig te verminder, sowel as 'n behoefte om brandstofdoeltreffendheid te verbeter en emissies te verminder. Dit het gelei tot die gebruik van liggewig strukturele materiale, soos Ti6A14V Allooi , wat die mees gebruikte titanium allooi in die Ruimte is. Hierdie allooi het 'n uitsonderlike krag-tot-digtheid-verhouding. Die studie dek ook gereedskapstaal 40CrMnMo7 wat in die gereedskap, Ruimte-en motor-industrie aangewend word. In die soeke na verbeterde prestasie word nuwe alternatiewe metodes om effektief bewerking van hierdie materiaal ondersoek. Een van die belangrikste kriteria tydens bewerking van hierdie materiaal is die bewerkbaar daarvan. Hierdie studie bespreek die huidige navorsing in hoë prestasie bewerking strategieë en tegnieke vir gevorderde materiale, soos Ti6Al4V en 40CrMnMo7. Die eienskappe wat hierdie materiaal voordelig maak vir die gebruik in die lug-en Ruimte-en motor-industrie, maak dit terselfdetyd moeilik om te sny. Die wydverspreide toepassing van Ti6Al4V in die lug-en Ruimte industrie moedig ondersoeke aan na koelstrategieë of -tegnieke om die instrumentlewe te handhaaf en te verbeter. Ti6Al4V het lae termiese geleidingsvermoë wat veroorsaak dat die hitte, wat gegenereer word tydens bewerking, versamel op die voorpunt van die instrument. Tydens verskillende eksperimente was die toepassing van eksterne saamgeperste lugblaas-verkoeling (droë sny), vloed verkoeling, hoë-druk-deur-die-spil-afkoeling (HPTSC) en aanpassings daarvan geondersoek. Die navorsingsprojek het ook die prestasie van 'n bedekkingslaag (TiAlN) en verskeie bedekkingslaagbehandelings geëvalueer. Die doelwit van die HPTSC aanpassing was om die koelmiddelstroom beklemming op die instrument oppervlak te verbeter, en effektiewelik die termiese versperring saam te pers, asook die skerf-teenoorinstrument kontak te verminder. Dit sou lei tot 'n afname in die instrumentverwarming en -slytasie. Die gewysigde tegnieke het daarin misluk om die instrumentlewe te verhoog, maar het tekens getoon van 'n toename in hitte verwydering vermoë onder die gegewe omstandighede. Dit is dus waargeneem dat lugblaasverkoeling (droë sny) die beste resultate gelewer het in die oorweging van sny materiale, bedekkingslaag, bedekkingslaagbehandelings en verkoeling strategieë of -tegnieke wat regdeur die eksperimente uitgevoer was.
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Vautherin, Béatrice. "Elaboration par projection plasma réactive sous très basse pression de dépôts de matériaux dans le système Aluminium-Titane-Azote." Thesis, Belfort-Montbéliard, 2014. http://www.theses.fr/2014BELF0239/document.
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La projection plasma sous très basse pression (communément désignée par son acronymeanglais VLPPS : « Very Low Pressure Plasma Spraying ») est un procédé émergent de traitement desurface par voie sèche permettant l’élaboration de dépôts métalliques et céramiques (type oxydes),sous des conditions de pression réduite, de l'ordre d'une centaine de Pascal, par utilisation d'un jet deplasma thermique. Un tel niveau de pression permet principalement la formation de dépôts parcondensation de vapeurs résultant de la vaporisation, partielle ou totale, des précurseurshabituellement sous forme solide. C'est principalement en cela que ce procédé diffère des procédésplus conventionnels de projection thermique, conduisant à la formation de dépôts par l'écrasement, lasolidification et l'empilement de particules liquides fondues dans un jet de forte énergie. En fonctiondes conditions de projection employées, les revêtements élaborés par VLPPS peuvent présenterdifférents types de microstructure, de colonnaires à lamellaires, de très denses à poreuses. Le modemixte de construction, caractérisé par la présence de vapeurs condensées et particules fonduesresolidifées peut également être rencontré.L'objectif global de ce travail est d'explorer le potentiel du procédé VLPPS en mode réactif envue de former des dépôts de matériaux présentant une fusion non congruente. Pour ce faire,l'aluminium et le titane ont été considérés comme matériaux métalliques précurseurs et l'azote commeélément réactif. Les matériaux qui pourraient résulter seraient alors des nitrures d'aluminium et detitane. Ces matériaux ont été sélectionnés avant tout comme matériaux démonstrateurs. Desapplications potentielles pourraient cependant rapidement déboucher en cas de performancessatisfaisantes : l'élaboration, sur de grandes surfaces, de couches de nitrures de titane et d'aluminium,présentant de bonnes résistances à l'oxydation ainsi que de bonnes propriétés tribologiques,notamment une résistance élevée à l'usure.Au cours de cette étude, des dépôts métalliques d’aluminium, titane et titane-aluminium et desdépôts composites nitrurés Al-AlN, Ti-TiN et TiAl-TiAlN ont été élaborés par projection VLPPS enmode réactif. Les dépôts composites nitrurés présentent par exemple des duretés moyennes plusimportantes que celles des dépôts métalliques. Ces dépôts renferment jusqu'à 30%at. d'azote et lescomposés TixN, AlN et TixAlN ont été clairement identifiésThe Very Low Pressure Plasma Spraying (VLPPS) is an emerging deposition process tomanufacture metallic and ceramic coatings, under a very low surrounding pressure, typically about onehundred Pascal, thanks to a thermal plasma jet. Such a pressure range allows principallymanufacturing coatings by condensation of vapors resulting from the vaporization, partial or total, ofsolid precursors, in most of the cases. This is the main difference of this process compared to moreconventional thermal spray processes, which form coatings by spreading, solidification and stacking ofparticles melted in a high energy jet. Depending upon the spray operating conditions, coatingsmanufactured by VLPPS exhibit different types of microstructures, from columnar to lamellar, fromdense to porous. The coating building dual mode, made of condensed vapors and molten particles isalso possible.The aim of this work is to explore in a reactive mode the VLPPS potential to manufacturecoatings made of materials exhibiting a non-congruent melting behavior. Here, for a demonstrationpurpose, Aluminum and Titanium were considered as the metallic precursors and Nitrogen as thereactive element. Therefore, materials which could result would be Aluminum and Titanium nitrides.Some possible applications could result directly from this study: the manufacturing on large surfacesof Aluminum and Titanium nitride layers, exhibiting good oxidation resistance and tribologicalproperties, especially a high wear resistance.In this study, metallic coatings of Aluminum, Titanium and Aluminum-Titanium and Al-AlN,Ti-TiN and TiAl-TiAlN coatings were manufactured by reactive VLPPS. Nitrided composite coatingsexhibit, for example, higher average hardness than metallic coatings, Those coatings embed up to 30at.% of Nitrogen and TixN, AlN and TixAlN compounds were clearly identified
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Giunta, Rachel K. "Durability of Polyimide/Titanium Adhesive Bonds: An Interphase Investigation." Diss., Virginia Tech, 1999. http://hdl.handle.net/10919/29449.
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When bonded joints are subjected to harsh environmental conditions, the interphase, the three-dimensional region surrounding the adhesive/substrate interface, becomes critically important. Frequently, failure occurs in this region after adhesively bonded systems are subjected to elevated temperature oxidative aging. In a previous study, this was found to be the case with a polyimide adhesive bonded to chromic acid anodized (CAA) Ti-6Al-4V. The objective of the current research has been twofold: 1) to investigate the effect of thermal aging on the interphase region of polyimide/titanium adhesive joints, and 2) to evaluate the method used in the current study for durability characterization of other adhesive/substrate systems.
The method used in this research has been to characterize the effect of elevated temperature aging on the following systems: 1) Notched coating adhesion (NCA) specimens and 2) bulk samples of dispersed substrate particles in an adhesive matrix. The NCA test has the advantages of an accelerated aging geometry and a mode mix that leads to failure through the interphase, the region of interest. The bulk samples have the advantage of an increased interphase volume and allow for the application of bulk analysis techniques to the interphase, a region that is traditionally limited to surface analysis techniques.
The adhesive systems studied consisted of one of two polyimide adhesives, LaRC⠢ PETI-5 or Cytec Fiberite⠢ FM-5, bonded to CAA Ti-6Al-4V. The model filled system consisted of a PETI-5 matrix with amorphous titanium dioxide filler. Through the use of the NCA test, it was determined that bonded specimens made with FM-5 lose approximately 50% of their original fracture energy when aged in air at 177°C for 30 days. This aging temperature is well below the glass transition temperature of the adhesive, 250°C. At the same time, the failure location moves from the anodized oxide layer to the adhesive that is directly adjacent to the substrate surface, the interphase region. Through surface analysis of this region, it is determined that the adhesive penetrates the pores of the CAA surface to a depth of 70 to 100 nm, promoting adhesion at the interface. With aging, the adhesive in the interphase region appears to be weakening, although analysis of the bulk adhesive after aging shows little change. This indicates that adhesive degradation is enhanced in the interphase compared to the bulk.
Analysis of the model filled system gave similar information. Specimens containing titanium dioxide filler had glass transition temperatures that were approximately 20°C lower than the neat polyimide samples. In addition, the filled samples contained a significant portion of low molecular weight extractable material that was not present in the neat specimens.
The tan delta spectra from dynamic mechanical thermal analysis of the filled specimens exhibited a shoulder on the high-temperature side of the glass transition peak. This shoulder is attributed to the glass transition of the interphase, a distinct phase of the polyimide which is constrained by adsorption onto the filler particle surfaces. As a function of aging time at 177° or 204°C, the shoulder decreases substantially in magnitude, which may relate to loss of adhesive strength between the polyimide and the filler particles.
From this research, it has been illustrated that information relating to the durability of adhesively bonded systems is gained using an interfacially debonding adhesive test and a model system of substrate particles dispersed in an adhesive matrixPh. D.
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森, 敏彦, Toshihiko MORI, 健治 広田, Kenji HIROTA, 直史 助田, Naofumi SUKEDA, 壮平 中屋, and Sohei NAKAYA. "化学結合を援用した生体適合性被膜性能の向上." 日本機械学会, 2003. http://hdl.handle.net/2237/9024.
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Gopalakrishna, Jayashri Sham. "Corrosion protection of advanced surface coatings for decorative applications." Swinburne Research Bank, 2008. http://hdl.handle.net/1959.3/35042.
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Thesis (PhD) - Swinburne University of Technology, School of Engineering and Science, 2008.A thesis submitted for the degree of Doctor of Philosophy, School of Engineering and Science, Swinburne University of Technology, 2008. Typescript. Includes bibliographical references (p. 189-204).
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Lilja, Mirjam. "Bioactive Surgical Implant Coatings with Optional Antibacterial Function." Doctoral thesis, Uppsala universitet, Nanoteknologi och funktionella material, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-209283.
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Device associated infections are a growing problem in the field of orthopaedics and dentistry. Bacteria adhering to implant surfaces and subsequent biofilm formation are challenging to treat with systemic administered antibiotics. Functionalization of implant surfaces with therapeutic coatings that are capable of inhibiting bacterial adhesion are therefore considered as a straight forward strategy to treat and prevent implant related infections. In this thesis, the use of crystalline, arc deposited TiO2 and biomimetic hydroxyapatite (HA) coatings were evaluated with respect to their potential as antibacterial surface modifications for bone-anchored implants. UV light induced photocatalysis of anatase dominated TiO2 coated surfaces was shown to provide a bactericidal effect against S. epidermidis under clinically relevant illumination times and doses. Major parts of the drug release work carried out was based on biomimetic HA (HA-B) coated fixation pins. The analysis of the coating characteristics revealed that the nanoporous structure of HA-B coatings in addition to the chemical composition and surface charge are essential parameters that influence the drug carrier performance. Loading by adsorption was demonstrated to be a feasible approach to quickly incorporate antibiotics. The controlled release of antibiotics was shown to facilitate bactericidal effects against S. aureus over application-relevant time periods, even when exposed to biomechanical forces during insertion into bone model materials. Antibiotic incorporation during coating growth was shown to promote somewhat longer drug release time periods than those obtained using adsorption loading. In summary, functionalization of implant surfaces with bioactive and biocompatible coatings is a promising concept to impact the clinical success for bone-anchored applications. The additional feature of optional, on-demand antibacterial properties of these coatings through either on-site drug release or photocatalytic antibacterial treatment is advantageous for the prevention and effective treatment of devices-associated infections. Both strategies provide an immediate response to the implant contamination by bacteria and are believed to contribute towards minimizing the origin of post-surgical infections, while at the same time improving the interfacial stability between implant and bone.
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Yumusak, Gorkem. "Evaluating the effect of titanium-based PVD metallic thin films on nitrogen diffusion efficiency in duplex plasma diffusion/coating systems." Thesis, University of Sheffield, 2019. http://etheses.whiterose.ac.uk/22894/.
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Paschoal, André Luís. "Avaliação da resistência à corrosão em meio fisiológico de metais revestidos com nitreto de titânio." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/88/88131/tde-02072003-093007/.
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Metais são bastante usados como materiais implantáveis, principalmente para dispositivos feitos na área de ortopedia. Há uma constante relação dos processos de corrosão nesse biomateriais com a agressividade do meio fisiológico. Usando quatro tipo de metais e ligas metálicas titânio puro, liga de titânio, aço inoxidável de baixo carbono e liga de cobalto o processo de corrosão foi estudado. Além disso, o desempenho desses materiais revestidos com nitreto de titânio foi avaliado. Dois processos de revestimento por PVD evaporação e magnetron sputtering foram executados, verificando a eficiência desses materiais em meio fisiológico - O melhor comportamento se deu para o revestimento obtido por evaporação. O mecanismo de corrosão predominante para as amostras foi indicado.Metals are very much used as implantable materials mainly for the construction of devices orthopaedic area. There is a constant concern about the corrosion process in those metallic biomaterials due to the aggressiveness of the physiological environment. By using four types of metals and metallic alloys pure titanium, titanium alloy, low carbon stainless steel and cobalt-chromium alloy the corrosion process in physiologic environment has been studied. Also, the performance of such materials coated with titanium nitrate was evaluated. Two PVD coating methods evaporation and magnetron sputtering were performed, and the efficiency of those materials in physiologic medium was verified. The best behaviour was found by the evaporation coating method. The predominant corrosion mechanism for coated samples was suggested.
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Brunell, Ian. "A fundamental study of nanocomposite hard coatings formed by ion-assisted deposition." Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300761.
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Jabir, Hamza. "Caractérisation à l'échelle locale des propriétés superélastiques d'alliages de titane massifs et sous forme de revêtements." Thesis, Rennes, INSA, 2018. http://www.theses.fr/2018ISAR0015/document.
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La superélasticité (SE) est la capacité d'un alliage à recouvrer sa forme initiale après une importante déformation. Cet effet, dû à une transformation martensitique réversible, est très convoité pour de nombreuses applications biomédicales. Les alliages nickel-titane sont les alliages les plus utilisés dans les applications fonctionnelles nécessitant de la SE. Cependant, l'utilisation de cet alliage dans les dispositifs biomédicaux est controversée par la présence du nickel, considéré comme élément cytotoxique et allergène. De ce fait, ces dernières années, une attention accrue a été portée aux alliages de titane [3-métastable pouvant constituer une alternative pour des applications biomédicales. En effet, ils ont l'avantage d'être élaborés à partir d'éléments biocompatibles et de présenter un comportement SE. L'objectif de cette thèse réside ainsi dans l'étude de la réponse SE des alliages de titane [3-métastable à différentes échelles dans leur forme massive et sous forme de revêtements. Deux alliages [3-métastable ont été élaborés: le Ti-27Nb {% at) et le Ti-24Nb-4Zr-4Sn (% mass). Les propriétés SE de ces alliages à l'état massif ont été caractérisées à l'échelle macroscopique et à l'échelle submicrométrique et comparées à celles du NiTi superélastique et du CP-Ti élasto-plastique. La nanoindentation a d'abord été utilisée pour sonder l'effet SE dans ces alliages massifs à l'échelle locale, et dans un deuxième temps, pour étudier l'effet de l'orientation cristallographique sur la réponse SE et mécanique à l'échelle du grain. Enfin, les propriétés mécaniques et SE de ces alliages sous forme de revêtements ont été évaluées avec ce même procédé de nanoindentationThe superelasticity is the ability of an alloy to recover its original shape after significant deformation. This effect, due to a reversible stress-induced martensitic transformation, is highly sought after for many biomedical applications. Nickel-titanium alloys that have a very large strain recovery (in bulk and thin film state), are the alloys currently used for functional applications requiring superelasticity. However, the use of this alloy in biomedical devices is controversial by the presence of nickel, considered as allergen and presumed cytotoxic for the body. As a result, in recent years, increased attention has been given to metastable f3 titanium alloys, which may be an alternative for biomedical applications. Indeed, they have the advantage of being elaborated from biocompatible elements and exhibit a superelastic behavior. The objective of this thesis lies in the study of the superelastic response of metastable f3 titanium alloys at different scales in bulk and thin film state. Two metastable f3 titanium alloys were elaborated: Ti-27Nb (at%) alloy and Ti-24Nb-4Zr-8Sn (wt %) alloy. The superelastic properties of these two bulk alloys were characterized at macroscopic and sub-micrometric scale and compared to superelastic NiTi and elastoplastic CP-Ti. The nanoindentation was first used to evaluate the superelastic effect of various bulk titanium alloys at local scale, and in a second time, to study the effect of crystallographic orientations on the superelastic and mechanical responses at the grain scale. Finally, the mechanical and superelastic properties of metastable f3 titanium coatings were evaluated with this same nanoindentation process
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森, 敏彦, Toshihiko MORI, 健治 広田, Kenji HIROTA, 鑑明 小林, Kanmei KOBAYASHI, 直史 助田, and Naofumi SUKEDA. "インプラントモデル材へのバイオセラミックスの傾斜機能溶射." 日本機械学会, 2001. http://hdl.handle.net/2237/9032.
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Tahhan, Abdulla. "Energy performance enhancement of crystalline silicon solar cells." Thesis, Brunel University, 2016. http://bura.brunel.ac.uk/handle/2438/14503.
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The work in this thesis examines the effects of the application of oxide coatings on the performance of the single crystalline silicon photovoltaic solar cells. A variety of potential oxide materials for solar cells performance enhancement are investigated. These films are silicon oxide, titanium oxide and rare earth ion-doped gadolinium oxysulfide phosphor. This study compares the electrical characteristics, optical properties and surface chemical composition of mono-crystalline silicon cells before and after coating. The first study investigates the potential for using single and double layers of silicon oxide films produced by low-temperature Plasma Enhanced Chemical Vapour Deposition (PECVD) using tetramethylsilane as a silicon precursor and potassium permanganate oxidising agent for efficiency enhancement of solar cells at low manufacturing cost. Deposition of the films contributes to the increase of the conversion energy of the solar cells on one hand while the variety of colours obtained in this study can be of great importance for building-integrated photovoltaic application on the other hand. The obtained results demonstrated a relative enhancement of 3% in the conversion efficiency of the crystalline silicon solar cell. In the second study, the effects of using a single layer of titanium oxide and a stack of silicon oxide and titanium oxide on the performance of solar cell are demonstrated. Moreover, this study shows the use of different sputtering configurations and oxidation methods. The experimental results showed a relative enhancement of 1.6% for solar cells coated with a stack of silicon oxide/titanium oxide. In the third study, silicon cells were coated with a luminescent layer consisting of down-converting phosphor, gadolinium oxysulfide doped with erbium and terbium, and a polymeric binder of EVA using doctor-blade screen printing technique. A relative enhancement of 4.45% in the energy conversion efficiency of PV solar cell was achieved. Also, the effects of combining silicon oxide layers together with the luminescent composite are also presented in this study.
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Pontin, Gabriel Inácio. "Microestrutura do metal de solda GTAW reforçado com carbonetos de titânio, parcialmente refundido por laser Nd:YAG pulsado /." Ilha Solteira, 2017. http://hdl.handle.net/11449/151338.
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Orientador: Juno GallegoResumo: O desgaste abrasivo é uma das causas de falhas em equipamentos e responsável por prejuízos nos processos industriais. Uma técnica capaz de minimizar os efeitos deste fenômeno é a aplicação de revestimentos duros nas superfícies críticas. Recentemente foram desenvolvidos revestimentos contendo carbonetos de titânio formados pela fusão de misturas contendo cavacos das ligas ASTM F67 e ASTM F136 sobre peças de aço-carbono ASTM A-36. Após a aplicação do processo de soldagem GTAW obteve-se significativa fração volumétrica de TiC grosseiro com elevada dureza. No presente trabalho foi investigada a refusão dessas soldas pelo processo de soldagem a Laser Nd:YAG pulsado. A microestrutura das amostras foi analisada por difração de raios-X (DRX), microscopia eletrônica de varredura (MEV) e microdureza Vickers. A caracterização microestrutural mostrou que houve refinamento dos carbonetos de titânio (TiC) na matriz ferrítica refundida com o Laser, cujo principal efeito foi um endurecimento do metal de solda. A caracterização mecânica demonstrou um aumento na microdureza da superfície do material. Este comportamento favorece o uso da refusão a Laser para a melhoria da qualidade das superfícies que demandam maior resistência ao desgaste abrasivo.
Mestre
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Bolduc, Mathieu. "Deposition of Commercially Pure Titanium Powder Using Low Pressure Cold Spray and Pulsed Gas Dynamic Spray for Aerospace Repairs." Thesis, Université d'Ottawa / University of Ottawa, 2013. http://hdl.handle.net/10393/24249.
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The objective of this study is to investigate the feasibility of depositing 1.5 mm thick titanium coatings, as a repair method for aerospace Ti-6Al-4V substrates, using two new commercially available processes: Low Pressure Cold Spray (LPCS) and Pulsed Gas Dynamic Spray (PGDS). The coatings produced were examined and characterized by their porosity level, microhardness, adhesion strength, particle flattening ratio, wipe tests, fracture surface type and wear tests. Phases and chemical composition were determined using X-Ray diffraction analysis and energy dispersive spectroscopy, respectively. It was found that both spraying processes are capable of producing dense, hard and oxide-free coatings using specific parameters. Finally, as a first step towards repair implementation of these processes, damages were simulated on Ti-6Al-4V samples, which were successfully repaired with low porosity and high hardness levels. The feasibility of repairs was confirmed, the next step will consist in qualification testing to assess coating performances under real life application.
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Sengottuvelan, Abirami [Verfasser], Aldo R. [Akademischer Betreuer] Boccaccini, Aldo R. [Gutachter] Boccaccini, and Emanuel [Gutachter] Ionescu. "Bioactivation of titanium dioxide scaffolds by functionalization and coating approaches / Abirami Sengottuvelan ; Gutachter: Aldo R. Boccaccini, Emanuel Ionescu ; Betreuer: Aldo R. Boccaccini." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2021. http://d-nb.info/1225938465/34.
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Wang, Chih-Sheng, and 王志勝. "Study of Titanium Disk Electrode Compound Coating." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/29830560822353851140.
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碩士國立雲林科技大學
機械工程系碩士班
90
In this study, it adopted the hollow spindle connected with disk electrode and the Titanium was to be the material of disk electric. Then, added the mixture that consisted of the carbon powder and dielectric into the spin disk electrode. According to the centrifugal force produced by the turning disk electrode, it would fling out the mixture. The SKD-61 and WC were to be the substrate. They proceeded the coating of surface and melted the electrode and substrate during the EDM process. After melting the carbon powder between the electrode and substrate, it and the carbon iron that was separated from the mixture would be blended to the coating layer. In order to know the effects of TiC layer according to the parameter and get the better parameter, this study used Taguchi method to do the research and did the analysis after the experiment. The spindle speed, peak current, pulse width and the carbon powder concentration were to be the parameters of the experiment. To probe the effect that the EDC TiC layer is to the change the parameter, this study focused the result including to the wear resistance of electrode, the surface roughness, the hardness, component and the thickness of the layer to analyze and discuss. The result was found that the more carbon powder concentration the higher hardness was. Moreover, if the releasing electricity last longer, it would get the maximum width of the layer. It produced the excellent surface when the current decreased.
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Yang, Chih-Hsiung, and 楊志雄. "Study of multi-coating on dental implant titanium." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/43845017156288481187.
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碩士中臺科技大學
醫學工程暨材料研究所
95
Titanium and its alloys are widely used in medical and dental applications. They have many excellent properties, including strength, corrosion resistance, toughness and biocompatibility. However, it is difficult to form a bond and develop the integration with bone tissue. Hydroxyapatite coatings on titanium have revealed good fixation to bone and increased bone ingrowth to the implant. Electrochemically deposition method was applied in this study because of several advantages, such as flexibility of coating highly irregular objects, arbitrary control of coating thickness and chemical composition. Electrochemical deposition ZrO2/HA coating on titanium substrates were conducted in 0.00625 M ZrO(NO3)2•2H2O solution and then in a mixing solution of 0.042 M Ca(NO3)2•4H2O and 0.025M NH4H2PO4. Deposited HA/ZrO2 coating on titanium were investigated by XRD, SEM/EDS, and polarization tests. Plate-like and acicular-like hydroxyapatite could be formed on Ti substrates by electrolytic deposition method at different potentials. XRD indicated that HA and Ti peaks were detected. The polarization test in artificial saliva revealed that HA/ZrO2 coating on Ti exhibited a reduced current density, confirming the better corrosion resistance. Furthermore, HA/ZrO2 coated specimen showed the higher bonding strength than that of HA coated specimen. The cell growth over the HA/ZrO2 coating showed better adhesion, spreading, and elongation.
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Chen, Jim-Shone, and 陳俊雄. "Calcium phosphate coating on titanium substrate by electrodeposition." Thesis, 1996. http://ndltd.ncl.edu.tw/handle/18857653734114499372.
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碩士國立成功大學
材料科學(工程)學系
84
AbstractThe calcium phosphate was deposited on titanium substrate by using electrolytic mixture of Ca(NO3)2（0.042M） and NH4H2PO4（0.025M） solutions with DC power supply. The cathode and anode were titanium substrate and platinum respectively. Various ratios of alcohol were added to increase the resistance of electrolyte and improve the quality of calcium phosphate coating.The result shows that the most uniform coating is obtained by adding 50％ ethylene alcohol in the solution and the power voltage and temperature of electrolyte are maintained at 20V and 40℃ respectively. Thick layer of 800um can be obtained for 3 hours deposition.The adhesion of calcium phosphate coating on the titanium substrate can be improved by post-treating in the electrolyte of similar composition without ethylene alcohol addition. The 3MPa adhesive strength is achieved for 120 hours post-treatment. The improvement of adhesion for calcium phosphate coating on titanium is performed by densifying the film from the outside surface to the interface of the coating.The calcium hydroxide appearing in the coatings can be dissolved in boiling water for 4 hours. The micrographs of the boiled sample indicated uniform distribution of calcium hydroxide in the coating.
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Li, Kuo-Bin, and 李國賓. "The Study of Titanium Aluminides Formed on Surface of Titanium Alloys by Laser Coating." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/39888910187406007553.
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Lo, S. C., and 羅松成. "Titanium Surface Modified by Hydroxyapatite Coating for Dental Implants." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/36761274221507698134.
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碩士明志科技大學
機電工程研究所
98
The purpose of this study was to explore the optimum parameters of plasma spray and RF sputter techniques for hydroxyapatite (HA) coated on Ti-6Al-4V surfaces of dental implants in order to promote the osseointegration and to reduce the risk of the infection after implant surgery. However, the plasma spray and RF sputter techniques will affect bonding strength, porosity, crystallinity, surface roughness and thickness of the hydroxyapatite coatings. Therefore, how to choose the parameters of the surface modification processing is very important. The optimization of the fabricating parameters can be to obtain an excellent combination of biocompatibility and mechanical properties of HA-coated titanium alloy implants. As to significant parameters, there are torch current, flow rate of gas, powder feed rate, stand-off distance and flow rate of powder carrier gas for plasma spraying, there are power, deposition time, and substrate speed for RF sputtering. In this study, HA-coating properties, such as crystallinity, purity, roughness, porosity, thickness, and response in simulation tests of the artificial body fluids, were examined. In phase I, the design and fabrication of HA-sputter target were studied. Owing to the equipment limitations in our lab, old pressing and sintering was used to manufacture. The results showed that the sintering shrinkage is about 15% and the cracks occurred. Therefore, hot pressing process is recommended in follow-up study to make HA-sputter target. In phase II, using rectangle plate Ti-6Al-4V substrates, the plasma HA spraying parameters was explored. According to the characteristic analysis, indicated that hydrogen content and powder feed rate are more significant factor. The amount of hydrogen upgrading (6-14 l/min) or the powder feeding rate of reduction (10 rpm) led HA powder easier to completely melt and to get dense coating, sheet-like structure and better bonding strength. In phase III, conducted the plasma spraying with disk substrates and the immersion tests in simulated body fluid (SBF), using the resulting parameters (b1, b2) in the phase II having the better coating properties and increasing coating thickness up to about 120 μ. After 28 days, the results revealed that, HA coatings in the SBF, crystallization level of the parameters b1 increased from 54.88% to 74.39%, decreased by about 41% of coating thickness, and calcium ion release increased from 44.9 ppm to 79.27 ppm; the crystallization level of the parameters b2 of increased from 46.34% to 73.17%, decreased by about 35% of coating thickness, and calcium ion release increased from 44.9 ppm to 80 ppm. In phase IV, investigated the difference of the nozzle transverse speeds and surface speeds in plasma spraying between plate and cylinder substrates. If the parameters are the same as in phase III, the cylinder titanium implants will melt to fail due to spraying temperature over the melting point. The results in phase IV exhibited that the nozzle transverse speeds of up to 400 mm / sec and surface speeds of down to (5 rpm) would be fine for the cylinder titanium implants. Finally, in phase V, chose the parameters in phase IV and HA plasma spraying of the dental implants was carried out. By SEM examination, showed that the HA coating coverage was uniform and the coating thickness was about 47-130 μm for parameter c1, about 47-130 μm for the parameters c2. In this study, plasma spray technology was successfully applied to HA material sprayed in titanium surface modification. From evaluation and characterization of HA coatings, found that both the parameters c1 (bonding strength of about 41.44 MPa, the thickness of about 47-130 μm, crystallization of 54.88 %, surface roughness Ra of about 6.20 μm) and the parameters c2 (bonding strength of about 47.36 MPa, the thickness of about 53-150 μm, crystallization of 46.34%, the surface roughness Ra of about 6.64 μm), are suitable for HA-coated titanium alloy dental implants and no significant amorphous components such as α-TCP, β-TCP or TTCP exist.
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Hu, Siou-Ming, and 胡修銘. "The Study of Zirconium-Titanium Conversion Coating Forming Process." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/85219438951428001167.
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碩士國防大學理工學院
化學工程碩士班
100
In this study, based on electro-galvanized substrate Zirconium-Titanium into treatment, to investigate the corrosion properties of non-chromium film. Experiments mainly use the LP of the corrosion resistance of the oxide film, EIS analysis of the impedance of the film density, SEM observation of film surface and cross-sectional patterns, XPS analysis of the distribution of elements of the Zirconium-Titanium film at different depths under the circumstances, and to deduce the composition of the oxides. The study results show that the Zirconium-Titanium conversion treatment on galvanized substrate, can form a protective layer in order to eliminate the corrosion reaction of the zinc substrate, but we can see of the film-forming ability to protect from salt spray results cannot be achieved in general industry set given anti-corrosion performance. Radical salts, add phosphate significantly improved solvent resistance of film and of film thickness will effectively enhance the salt spray test results from 120nm to 900nm, add phosphate of zirconium titanium film to salt spray time upgrade from 48hr to 144hr, said to add the zirconium titanium phosphate film can reach the traditional chromate coating corrosion performance. Keywords: non-chromium film, corrosion resistance, electro-galvanized
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Chai-Che and 何佳哲. "RGDC peptide coating on electrodeposited nano-gold titanium substrates." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/98461172821312198798.
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碩士中山醫學大學
口腔材料科學研究所
96
The objective of the study was to evaluate the feasibility of nano-structured Au deposited onto titanium substrates using electrodeposition. After which, immobilization of Alginine–Glycine–Aspartate–Cysteine (RGDC) peptide onto nanogold-coated titanium surface was further performed for implant applications. Characterization of the Au nano-particles electrodeposited Ti and peptide immobilization were performed using a thin film X-ray diffractometer (TFXRD), field emission scanning electron microscope (SEM), and high resolution X-ray photoelectron spectroscopy (XPS), in addition to electrochemical methods including electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The results showed that Au nano-particles could be easily electrodeposited on titanium surface. The mean particles size of 60 nm, 110 nm and 80 nm would be obtained following electrodeposition at different applied potential, respectively. XRD patterns indicated a polycrystalline orientation of the gold phase. The characteristic peaks were ascribed to (111), (200), (220), and (311) crystal faces. XPS spectrum illustrated that the RGDC peptide could be successfully immobilized on nano-gold-deposited Ti substrates via self-assembly of Au-S bonding. This procedure might be used as an alternative way for peptide or other bioactive molecules immobilization. However, the results of MG63 osteoblast-like cells cultured onto RGDC-Au-coated titanium surface showed that it did not benefit for cells attachment.
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Lu, MingShane, and 盧明憲. "Synthesis of Nanosized TiO2 Coating Solution from Titanium Tetrachloride." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/39570920749229055138.
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碩士國立中央大學
化學工程研究所
89
TiO2 has been used as a coating material because of its excellent UV light-scattering effect, high refractive index, and chemical stability, even in acidic or basic environment. TiO2 in anatase phase for applications in optical or electronic devices has generally been adopted in the form of a thin film. The aim of this study was to prepare suspended titanium dioxide solution with high concentration. Titanium tetrachloride was used as a precursor. It was slowly added to the distilled water at 5 ℃. Aqueous solution of sodium hydroxide was added to adjust the pH of the system to 8-12. After aging for a period of time, the peptizate sol was filtered and sufficiently washed. The filtered cake was repulped in water. Hydrochloric acid was slowly added to the solution with stirring. After condensation reaction and crystallization, a transparent suspended TiO2 solution was formed. XRD results show that the crystalline phase was anatase. The suspended TiO2 particles were rhombus primary particles with the major axis ca. 20 nm and the minor axis ca. 5 nm. The sample prepared at pH 8 has the largest surface area of 141 cm3/g, and it was microporous. The compositions of the solution which has the smallest suspended TiO2 particles are TiO2: HCl (35 % HCl)= 1: 1 (molar ratio), concentration of TiO2 = 10 % and HPC with viscosity of 150-400 cps was added as a surfactant. The transparent thin film substrates could be obtained through dip-coating the glass in TiO2 coating solution. The dip-coating on glass can be less than three times to have one monolayer TiO2. The transparent TiO2 thin film has super-hydrophilicity after being illuminated by UV light.
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Lin, Jian-You, and 林建佑. "Hydroxyapatite/Chitosan Composite Coating on Titanium by Hydrothermal Method." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/6bp55u.
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LIN, LIANG-WEI, and 林亮葦. "HA Coating on Pure Titanium and Ni-Ti alloys by Ultrasonic Mechanical Coating & Armouring." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ksqfy6.
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碩士國立高雄應用科技大學
模具工程系
105
In this study, Hydroxyapatite (HA) was coated on Ti and NiTi surface by ultrasonic mechanical coating & armouring (UMCA). The alloy surface was previously precoated with a suspension of a liquid and HA powder. Then, the alloy was fixed to the top of the vibration chamber and the alloy surface was subjected to high-energy zirconia ball impacts. The effects of the UMCA duration and the precoating times on the HA amount containing on Ti surface and adhesion between coating and Ti were investigated. An extended UMCA duration induced a high adhesion of the coating on the substrate, but the surface contained less HA amounts. However, increasing the precoating time resulted in a high HA amount and the worse adhesion of the coating. The optimal parameter produced a coating containing 15.9 at% Ca and 12.3 at% P with thickness of 5.4 μm. Cross-sectional TEM observation indicated that the coating comprising most of HA and a few Ti particles closely contacted with Ti substrate. The coating exhibited a better bioactivity than Ti evaluated by immersion tests in simulated body fluid. The thickness of the coating on NiTi is significantly less than that on Ti. It is because pseudoelastic characteristic does not allow NiTi to deform well during UMCA and induces the coating with a relatively loose structure comparing with the coating on Ti. Putting Ti powder in the vibration chamber can improve the adhesion of the coating on NiTi. The optimal parameter produced a coating containing 15.9 at% Ca and 5.3 at% P with thickness of 500 nm. Ball-impacts also changed the microstructure of the NiTi near the interface. The substrate surface is consisted of an amorphous layer and nanocrystalline layer with the increase of the distance from the interface. After UMCA, the NiTi still exhibits shape memory ability and it has a higher transformation temperature than the as-received NiTi.
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Lu, Shi Zhong, and 呂世仲. "The research of electrolytic ZrO2 coating on commercial pure titanium." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/00173383816423913127.
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Chao, Meng-En, and 趙蒙恩. "STUDY ON PHOTOINDUCED BACTERICIDAL KINETICS ON TITANIUM OXIDE CONTAINED COATING." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/26643865853254530297.
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碩士大同大學
生物工程學系(所)
94
Titanium dioxide( TiO2) photocatalysts generate free radicals when illuminated by lights having wavelength shorter than 385 nm. These radicals are able to attack bacteria, and may therefore be efficacious in reducing bacterial pollution. In this study, a highly sensitive method for the evaluation of the photoinduced disinfection of a commercial TiO2-contained coating under a ultraviolet(UV) light irradiation was developed. Suspension of Enterococcus faecium, Staphylococcus aureus, Pseudomonas aeruginosa, E.coli, or Candida albicans was put on a surface containing TiO2 and was overlaid with a coverglass. During the UV irradiation for up to 60 min the decay of microbial viability nearly followed the first order kinetics. In the present work, we demonstrate a novel method for the evaluation of bactericidal efficacy of photocatalysts.
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Wang, Cong-Yu, and 王琮郁. "Surface Modification of Biomedical Titanium Alloys by Electrical Discharge Coating." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/38q993.
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碩士國立高雄應用科技大學
模具工程系
103
This study modified pure titanium (Ti) and titanium-tantalum (Ti-Ta) surface by electrical discharge machining (EDM) using distilled water containing hydroxyapatite as dielectric fluid. The effects of machining parameters on the machining ability and surface characteristics of the Ti alloys were investigated. Results show adding HA in distilled water decreased the material removal rate (MRR) of Ti alloys. However, the MRR increased with increasing HA concentration owing to ignition delay time reduced. The addition of Ta to Ti clearly reduced the MRR, electrode wear rate, surface roughness and recast layer thickness, which was attributed to the increased melting temperature and thermal conductivity of the materials. The recast layer comprised titanium, (tantalum), oxygen, calcium, and phosphorus. The lower discharge current the more amounts of calcium and phosphorus containing in the recast layer was found. After hydrothermal treatment at 150 ℃for 6 h, crystals were precipitated on the EDMed surface, which exhibited hydrophilic tendencies.
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Huang, Cheng-Wei, and 黃振瑋. "Fabrication of a composite coating on titanium with antibacterial ability." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/xkk6px.
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Wang, Yu-Sheng, and 王昱勝. "The Study of micro-arc oxidation on The Titanium Coating." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/68905445253290196058.
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碩士國立臺灣大學
機械工程學研究所
104
In this paper, it’s compared the qualities of the titanium oxide layer modified by micro-arc oxidation (MAO) under difference process conditions, they were compared with applied current, acting time, pulse on time and pulse off time. From obeservating the surface topography of SEM and optical microscope, it is shown impact of difference process conditions to the qualities of titanium oxide layer. Moreover, ot can be demonstrated the optimization conditions to generate the titanium oxide layer by MAO. The experiments are divided into the three parts. In first part, it was designed to the four current conditions at the same acting time and same pulse conditions. The results show generation the oxide film at current 0.5 A, 0.6 A and 0.8A it have TiO2 white powder.