Rozprawy doktorskie na temat „Tungstene carbide”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Tungstene carbide”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Roure, Sophie. "Densification des mélanges de poudres WC-Co : de la compression au frittage". Grenoble INPG, 1996. http://www.theses.fr/1996INPG0222.
Pełny tekst źródłaHarry, Emmanuelle. "Stabilité mécanique et modes d'endommagement de revêtements multicouches à base de tungstène et de tungstène-carbone élaborés par PVD". Grenoble INPG, 1998. http://www.theses.fr/1998INPG0071.
Pełny tekst źródłaLavergne, Olivier. "Mécanismes de dissolution et de précipitation dans les carbures cémentés WC/Co". Grenoble INPG, 1997. http://www.theses.fr/1997INPG0214.
Pełny tekst źródłaLindahl, Bonnie. "Equilibrium Study of Chromium Containing Cemented Carbides : Solubility of chromium in tungsten carbide and η-phase". Thesis, KTH, Materialvetenskap, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-49974.
Pełny tekst źródłaGuiz, Robin. "Influence d’additions de titane/tungstène et de vanadium sur la précipitation de carbures secondaires au sein d’alliages modèles de type HP". Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEM011/document.
Pełny tekst źródłaHP alloys are typically used as steam methane reforming tubes in the petrochemical industry. During service, they are exposed to temperatures between 700°C and 1000°C under gaz pressure of several MPa. Their as-cast microstructure, together with fine in-situ secondary precipitation, provide these alloys with an excellent resistance to creep deformation. Nevertheless, after long-time ageing, coarsening of secondary carbides leads to the weakening of the tubes and therefore to an accelerated damaging.The effects of some alloying elements (V, Ti/W) on secondary precipitation of M23C6 and NbC carbides were investigated through numerical simulations performed with TC-PRISMA software. On the basis of encouraging results in terms of precipitation optimization, two model HP-type alloys were cast at the laboratory and aged in the range of temperatures corresponding to service conditions. As-cast microstructures were first compared with an industrial "standard" alloy. Then, secondary precipitation were characterized for all the alloys and all ageing temperatures. Microstructural investigation highlighted the beneficial effect of vanadium and titanium/tungsten additions on secondary precipitation characteristics
Agode, Kofi Edoh. "Analyse et modélisation du comportement à l’usure des outils de coupe en carbure de tungstène pour différentes teneurs en cobalt lors de l’usinage de l’alliage de titane Ti-6Al-4V". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0141.
Pełny tekst źródłaDue to their high hardness and wear resistance, cemented carbide (WC-Co) is the main material used to manufacture machining tools and forming tooling, as well as wear parts requiring high hardness and high precision. The modification of tungsten carbide microstructure, and more particularly its cobalt content, is currently attracting the greatest interest from manufacturers to develop new grades tools with high performance, and then expand new markets.This thesis aims to study the effect of the cobalt content of carbide tools on the measured values and wear mechanisms when machining hard superalloys such as the aeronautical titanium alloys Ti-6Al-4V. Both experimental and numerical research work are devoted on one hand to the understanding of the microscopic damage mechanisms leading to the macroscopic wear of the WC-Co composite and on the other hand, to the influence of the cobalt content on the behavior of the WC-Co taking into account the mechanical-microstructure-damage coupling.On the basis of an experimental analysis, the identification of the macroscopic and microscopic physical phenomena involved at the tool/chip and tool/workpiece contact interfaces was conducted. Machining tests were firstly carried out on the tool-material couple WC-Co/Ti-6Al-4V with different cobalt contents for the tools (from 6 to 15%). In a second step, a tribological characterization of the same tool-material couple was carried out to evaluate the influence of the cobalt content and the contact conditions (sliding speed, applied force) on the friction coefficient and wear. However, the inaccessibility of the contact zones during machining and the tribological tests did not allow a complete description of the wear mechanisms observed, whether macroscopic mechanisms (adhesion, abrasion, deformation, ...), or microscopic mechanisms (cracking, damage of the WC and Co phases). The numerical simulation using finite elements (FE) proved to be a very interesting complementary tool for the analysis of these wear mechanisms.Our modeling strategy focused on the response of WC-Co at the microstructure scale for the thermomechanical loading close to that obtained by machining. The proposed model takes into account the behavior of the WC and Co phases separately and that of the interfaces WC-WC and WC-Co of the composite. This strategy allowed to study and identify parameters influencing the behavior of the microstructure from the elastic stage to the damage initiation. A good agreement was obtained between the results of the numerical behavior at the initiation of damage in the microstructure and those of the experimental observations in terms of the effects of the cobalt content in the tungsten carbide and of the applied machining conditions
Gianni, Lorenzo. "Electrodialytic recovery of tungsten and cobalt from tungsten carbide scrap". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022.
Znajdź pełny tekst źródłaDeshpande, Pranav Kishore. "Infrared Processed Copper-Tungsten Carbide Composites". University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1025107651.
Pełny tekst źródłaKelley, Andrew III. "Tungsten carbide-cobalt by Three Dimensional Printing". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/32316.
Pełny tekst źródłaIncludes bibliographical references (p. 69-70).
Three Dimensional Printing is an additive manufacturing process for rapid prototyping ceramic and metallic parts [Sachs, et al, 1990]. Green (not sintered) tungsten carbide-cobalt parts must have a density greater than 50% of the theoretical density, 14.9 g/cc, for proper sintering and post-processing. Two approaches were assessed for feasibility and robustness: printing slurry into tungsten carbide-cobalt spray dried powder and printing a solvent in spray dried tungsten carbide powder that readily dissolves. For slurry administered to a powder bed of solid, spherical particles, it has been found that the resulting packing primitive packing fraction increases almost linearly with the volume loading of the slurry over a range of powder size. The increase in density is approximately half what would be calculated by assuming that the slurry fills all the porosity in the powder bed. The maximum green density achieved by printing slurry into a spray dried tungsten carbide-cobalt bed was 41%, midway between the lower bound calculated by assuming the vehicle in the slurry infiltrates only the large pores between the spray dried power and the upper bound calculated by assuming that the vehicle of the slurry also infiltrates the find pores within a spray dried granule. A re-dispersible spray dried powder (38-53 micron size range) was fabricated using only the Duramax 3007 dispersant as the binder. This powder redisperses in water. Administering a drop of water to this powder resulted in primitives with 47% packing density, but which had significant quantities of 80 micron voids.
(cont.) Several lines of evidence pointed to the hypothesis that the voids were the result of trapped air. Two methods were successfully employed to nearly eliminate such voids. In one approach, the droplet of water wvas administered to the powder bed under a vacuum of between 25 and 40 torr and air was admitted to the chamber to 1 atmosphere after different intervals of time ranging from 30 seconds to 10 minutes. In another approach, the ability of water to absorb CO₂ was used to "getter" any trapped gas into the liquid. Water was administered to a powder bed under a CO₂ environment at room temperature. After a 2 minute period, intended to allow the spray dried powder to substantially re-disperse, the temperture of the powder bed was lowered to 0-5 degrees Centigrade in order to increase the amount of CO₂ which could be absorbed in the water and "switch on" the gettering of the trapped gas.Controls were run with the same procedure in air. The primitives made under CO₂ were nearly void free and had densities as high as 52%, while the controls were not significantly different than primitives made at room temperature in air.
by Andrew Kelley, III.
S.M.
Deshpande, Pranav K. "Copper-tungsten carbide composites with infrared processing". Cincinnati, Ohio : University of Cincinnati, 2002. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=ucin1025107651.
Pełny tekst źródłaBjörklund, Kajsa. "Microfabrication of Tungsten, Molybdenum and Tungsten Carbide Rods by Laser-Assisted CVD". Doctoral thesis, Uppsala University, Department of Materials Chemistry, 2001. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-1593.
Pełny tekst źródłaThin films of refractory metals and carbides have been studied extensively over many years because of their wide range of application. The two major techniques used are Chemical Vapour Deposition (CVD) and Physical Vapour Deposition (PVD). These can result in the deposition of two-dimensional blanket or patterned thin films. Laser-assisted Chemical Vapour Deposition (LCVD) can provide a maskless alternative for localised deposition in two and three dimensions. This thesis describes LCVD of micrometer-sized tungsten, molybdenum and tungsten carbide rods. The kinetics, phase composition and microstructure have been studied as a function of in situ measured laser induced deposition temperature.
Tungsten and molybdenum rods were deposited by hydrogen reduction of their corresponding hexafluorides, WF6 and MoF6, respectively. Single crystal and polycrystalline tungsten rods were obtained, depending on the H2/WF6 molar ratio and deposition temperature. The molybdenum rods were either single crystals or dendritic in form depending on experimental conditions. The field emission characteristics of the tungsten single crystals were investigated. The results showed LCVD to be a potential fabrication technique for field emitting cathodes.
Nanocrystalline tungsten carbide rods were deposited from WF6, C2H4 and H2. TEM analysis showed that the carbide rods exhibited a layered structure in terms of phase composition and grain size as a result of the temperature gradient induced by the laser beam. With decreasing WF6/C2H4 molar ratio, the carbon content in the rods increased and the phase composition changed from W/W2C to WC/WC1-x and finally to WC1-x/C.
Björklund, Kajsa. "Microfabrication of tungsten, molybdenum and tungsten carbide rods by laser-assisted CVD /". Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2001. http://publications.uu.se/theses/91-554-5197-7/.
Pełny tekst źródłaEscolle, Bérenger. "Optimisation des outils de micro-fraisage destinés à l'usinage des aciers durs : cas des micro-fraises hémisphériques". Thesis, Besançon, 2015. http://www.theses.fr/2015BESA2023.
Pełny tekst źródłaThe aim of this PhD work is optimized by experimental approach with 0.5 mm diameter micro-ball-end mills made from micro-grain tungsten carbide and PVD coated for hardened tool steels machining. The experimental data are obtained on machining of hardened steel (54/55HRC), typically used for the production of plastic injection molds. Results permit to highlight some cutting phenomena of wear and dynamic behavior of the process related tool, and changes depending on the type of milling considered and selected cutting conditions. The geometry of the tool and dynamic behavior are primarily discussed here. As a first step, the study of different carbide grades, surface preparation and optimization of global and local geometries of micro-cutters helped provide an efficient model for our partner Magafor toolmaker. In a second step, the modelling of micro-milling is discussed and an analytical model for cutting forces calculation is introduced. It was demonstrated the identifying limits of the specific cutting coefficients in our case. Then, a test of finite element modelling of micro-milling is made in order to estimate the potential of such a method for the study of the dynamic behaviour of micro-mills
Durand, Corinne. "Atomisation de gouttes liquides sur une cible tournante microstructurée". Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENI035.
Pełny tekst źródłaThe aim of this work is to design a spray tool for the production of tungsten carbide powder for the companyTechnogenia, located in Saint-Jorioz (74). Thus, we have studied a new design of rotary atomizer based onatomization surface oriented at a non-zero incidence angle. Such an orientation can then allow to use moreeffectively the rotation frequency of the atomizer and the centrifugal and Coriolis forces. From this base reflection,three geometries of atomization surface were studied : smooth surfaces, surfaces with serrated structurationsalong their trailing edge and multi-perforated surfaces.The different destabilization modes of liquid flows were observed through high-speed videos of the different stagesof the single drop impact on each atomization surfaces. The atomization process can thus vary between liquid jetbreakup caused by Rayleigh-Plateau instabilities and liquid sheet breakup caused by Rayleigh-Taylor instabilitiesand/or initiating of holes in liquid films or sheets. Videos of aqueous sprays and microscopic observation of metalpowders allow us to characterize sprays. On all of our experiments, we observe that the atomisation gets better(producing finer spray), as the frequency of rotation increases. Although the textured surfaces are compatiblewith usual liquids (aqueous or organical), they can’t stand the constraints imposed by metal with a high meltingtemperature such as tungsten carbide, the object of this thesis. Therefore, only the smooth surfaces are nowthe subject of an industrial development to produce metallic powder with Technogenia company
Moche, Hélène. "Utilisation du carbure de tungstène-cobalt (WC-Co) comme témoin positif génotoxique nanoparticulaire et étude de la génotoxicité de candidats nanovecteurs de médicaments". Thesis, Lille 2, 2014. http://www.theses.fr/2014LIL2S024/document.
Pełny tekst źródłaNanomaterials are used in many industrial sectors, and many nanomaterial-containing consumer products are already available. In this context of increasing human exposure to nanomaterials, the evaluation of their genotoxicity is of significant importance. However, the relevance of routinely used genotoxicity assays, developed for non-nanoparticular products, is often questioned for the evaluation of nanomaterials. A nanoparticulate reference positive control would therefore constitute an important step to a better testing of nanomaterials genotoxicity, ensuring that test systems are actually appropriate and/or allowing the validation of new ones.Firstly, we studied the possibility of using commercially-available tungsten carbide-cobalt (WC-Co) nanoparticles, previously characterized for physicochemical properties (size distribution and charge in used media), as positive control in three in vitro genotoxicity assays. The mouse lymphoma thymidine kinase gene mutation assay, the micronucleus assay studying chromosomal aberrations and the comet assay detecting primary DNA damage were performed. The last two assays were realized in two cell types, the mouse lymphoma cell line L5178Y and primary cultures of human lymphocytes. Our results show that WC-Co nanoparticles could be used as positive control in these in vitro genotoxicity assays, according to cell type and treatment schedule.Secondly, we investigated the mechanisms of action involved in WC-Co nanoparticles genotoxicity. Detection of centromeres in micronuclei using fluorescence in situ hybridization (FISH) show the involvement of both clastogenic and aneugenic activities. This was correlated with the results of a chromosome aberration assay on human lymphocytes blocked in metaphase, showing chromatid breaks and polyploid cells. Moreover, as oxidative mechanisms are the most described for nanomaterials, we studied oxidative DNA damage using the modified in vitro comet assay with the DNA repair enzyme formamidopyrimidine DNA glycosylase (FPG). We also detected a production of hydroxyl radicals using electron paramagnetic resonance in suspensions of WC-Co nanoparticles with and without cells. While performing high-throughput assays on WC-Co nanoparticles in three human cell lines corresponding to the main target organs for nanomaterials (A549 lung cell line, Hep3B liver cell line and Caki-1 kidney cell line) it was confirmed that oxidative stress play a significant role in the toxicity of WC-Co nanoparticles. Indeed, the production of reactive oxygen species in cells exposed to WC-Co nanoparticles was correlated to the observation of cytotoxicity and genotoxicity, studied using the detection of γH2AX foci.Finally, we carried out the most relevant genotoxicity assays to study nanodiamonds and lipid nanocapsules, which constitute promising nanovectors for drug delivery. The in vitro comet and micronucleus assays were performed on other cell types mimicking target organs: the T84 intestinal epithelial cell line and the 16-HBE bronchial epithelial cell line exposed to nanodiamonds of three different sizes, and human lymphocytes exposed to lipid nanocapsules of three different sizes and three different charges
Fernandes, Cristina Maria da Silva. "Sputtering on the production of tungsten carbide based composites". Doctoral thesis, Universidade de Aveiro, 2008. http://hdl.handle.net/10773/2316.
Pełny tekst źródłaO principal objectivo deste trabalho é estudar a viabilidade do revestimento de partículas de carboneto de tungsténio (WC), como etapa alternativa à mistura convencional de componentes. Para tal, revestiram-se pós de WC com aço inoxidável 304 (AISI), por uma técnica de deposição física em fase de vapor, denominada pulverização catódica. O outro objectivo deste trabalho incide na investigação das potencialidades das ligas de Fe/Cr/Ni como ligantes nos compósitos à base de WC. Para estudar a viabilidade da técnica de deposição como alternativa à mistura de componentes, depositaram-se quantidades variáveis de aço inoxidável (entre 1 e 10%) nas partículas de pó de WC. Alternativamente, e para efeitos de comparação, prepararam-se composições similares por mistura convencional. Os resultados da caracterização de pós revestidos foram motivadores, uma vez que indicaram que as partículas de WC possuíam revestimentos nanocristalinos bastante uniformes e que todos os elementos constituintes do aço foram depositados nas proporções existentes no alvo. Estes pós apresentam ainda boa escoabilidade e prensabilidade, uma resistência à oxidação acrescida e elevada estabilidade em soluções aquosas a pH ácido e neutro. A investigação do aço inoxidável como ligante de sinterização mostrou que os elementos constituintes do aço são eficazes na promoção da densificação dos compactos à base de WC. Os pós revestidos apresentaram uma sinterabilidade e reactividade superiores às das misturas convencionais. Atingiram-se valores superiores de densificação nos pós revestidos, sobretudo com as perdas de peso controladas através do ciclo térmico ou atmosfera de sinterização. A cinética de formação de fases, designadamente de M6C, é mais rápida nestes pós, mas a quantidade formada pode ser reduzida ou mesmo eliminada, aumentando o teor de níquel no ligante e com pequenas adições de carbono. Os resultados da caracterização mecânica de compósitos preparados com os pós revestidos evidenciaram um bom compromisso entre a tenacidade e dureza, superior ao observado em amostras preparadas convencionalmente. Por outro lado, os ligantes à base de aço inoxidável mostraram uma relação de tenacidade versus dureza superior à existente em dados publicados para compósitos de Co. A presença de M6C aumentou a dureza dos compósitos, sem degradar a sua tenacidade, enquanto que o aumento do teor de níquel reduziu substancialmente a dureza do material.
The main objective of this work is to study the feasibility of the tungsten carbide (WC) particle covering as an alternative to the conventional mixture of components. For such purpose, WC powders were coated with stainless steel 304 (AISI) by a physical vapour deposition technique, called sputtering. The other objective of this work is to study the potentiality of Fe/Cr/Ni alloys as binders in WC based composites. To study the viability of the deposition technique as an alternative to the mixture process, different amounts of stainless steel (between 1 and 10 wt.%) were deposited on WC powder particles. Alternatively, similar compositions have been prepared by conventional mixture, for comparison. The results of the characterization of coated powders are very promising, since they indicated that the WC particles have very uniform nanocrystalline coatings and that all the elements were deposited in the same proportions of the target. These powders present good flowability and prensability, an increased oxidation resistance and high stability in aqueous solutions, at acid and neutral pH values. The study of the stainless steel as a sintering binder demonstrated that the steel constituent elements are efficient in the promotion of densification of the WC based composites. Coated powders present higher reactivity and sinterability than conventional mixtures, especially when weight losses are controlled through the thermal cycle or sintering atmosphere. The kinetic of phase formation, namely M6C, is faster in these powders, but the amount formed can be reduced, or eliminated, by increasing the Ni amount in the binder and by small carbon additions. The results of the mechanical characterization of composites prepared with coated powders evidenced a good compromise between hardness and toughness, higher than the one observed in conventionally prepared composites. On the other hand, the composites with stainless steel based binders show superior values of toughness versus hardness than the ones reported in literature for composites with cobalt. The presence of M6C increases the composites hardness, without degrading its toughness, while the increase of Ni substantially reduces the hardness of the material.
Crause, Chantelle. "Synthesis and application of carbene complexes with heteroaromatic substituents /". Access to E-Thesis, 2004. http://upetd.up.ac.za/thesis/available/etd-05252005-145146/.
Pełny tekst źródłaHenon, Albin. "Étude du frittage par résistance de matériaux composites : cas du système Ag-WC". Grenoble INPG, 1997. http://www.theses.fr/1997INPG0136.
Pełny tekst źródłaBernard, D'arbigny Julien. "Synthèse, caractérisation et mise en forme d'électrodes nanocomposites platine / carbure de tungstène pour les piles à combustibles à membrane haute température". Thesis, Montpellier 2, 2012. http://www.theses.fr/2012MON20144/document.
Pełny tekst źródłaThe objective of this work was to develop alternative suitable materials to increase operating temperature of a Proton Exchange Membrane Fuel Cell. The increase of the operating temperature (150 - 250 °C) is attractive for cost reduction and reliability in terms of reaction kinetics, catalyst tolerance, heat rejection and water management. Our work was focused on tungsten carbide which has an high electrical conductivity and exhibits a significant catalytic activity for hydrogen oxidation and oxygen reduction in acidic environment. We have reported a novel approach to produce tungsten carbide microspheres (TCM) with an high surface area (68 m2.g-1 including only 4 % of residual carbon) and an unusual architecture. Platinum nanoparticles were prepared by polyol method and were then deposited on TCM. Physical, chemical as well as electrochemical characterisations of WC supported platinum nanoparticles Pt/WC are described and discussed in comparison with a platinum electrocatalyst on a commercial carbon support (Vulcan XC-72R). Membrane Electrode Assembly was then prepared by coating - decal process, and characterised by single cell test and compared to conventional Pt/C assembly. Phosphoric acid doped polybenzimidazole PBI(H3PO4) was used as electrolyte to replace Nafion membrane in order to carry out fuel cell testing at higher temperature
Zhuang, Yipping. "Mechanisms of alkane reactions over platinum and tungsten carbide catalysts". Doctoral thesis, Universite Libre de Bruxelles, 1995. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/212599.
Pełny tekst źródłaPuzz, Travis Earl. "DEVELOPMENT OF A TUNGSTEN CARBIDE-NICKEL BRAZE ALLOY HARDFACE COATING". MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-11082007-141548/.
Pełny tekst źródłaTran-Nguyen, Diem-Hang. "Direct production of tungsten carbide via the FFC-Cambridge process". Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610280.
Pełny tekst źródłaHumbert, Michael P. "Catalytic properties of platinum and tungsten carbide-based bimetallic surfaces". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 167 p, 2010. http://proquest.umi.com/pqdweb?did=1992441341&sid=11&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Pełny tekst źródłaDyson, Glynn. "The low-temperature chemical vapour deposition of tungsten carbide coatings utilising the pyrolysis of tungsten hexacarbonyl". Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/33243.
Pełny tekst źródłaSallom, Zuhair Kamil. "Evolution of particle characteristics in sintered hard metal". Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236236.
Pełny tekst źródłaVatry, Aude. "Mise en suspension par laser de poussières générées lors du fonctionnement des réacteurs de fusion". Thesis, Aix-Marseille 2, 2010. http://www.theses.fr/2010AIX22105/document.
Pełny tekst źródłaDuring tokamak operation, plasma-wall interactions lead to material erosion processand dusts production. These dusts are mainly composed by carbon and tungsten, with sizesranging from 10 nm to 100 $m. For safety reasons and to guarantee an optimum reactorfunctioning, the dusts have to be kept in reasonable quantity. The dusts mobilization is a firststep to collect them, and the laser is a promising technique for this application. To optimizethe cleaning, physical mechanisms responsible for dust ejection induced by laser have beenidentified. Some particles, such as aggregates, are directly ablated by the laser. The metaldroplets are ejected intact by an electrostatic force, induced by the photoelectrons. We alsocharacterized the particles ejection to choose an appropriate collection device
Zellner, Michael. "Tungsten carbides as potential alternative direct methanol fuel cell anode electrocatalysts". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 213 p, 2006. http://proquest.umi.com/pqdweb?did=1172119451&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Pełny tekst źródłaDi, Maio Davide. "Characterisation of tungsten carbide-based coatings produced by chemical vapour deposition". Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.418634.
Pełny tekst źródłaKausar, Rehana. "Surface studies of silicon carbide deposition on carbon and tungsten substrates". Thesis, University of Salford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.314000.
Pełny tekst źródłaBrunet, Pierre. "Fusion en creuset froid et pulvérisation de carbure de tungstène". Grenoble INPG, 1987. http://www.theses.fr/1987INPG0110.
Pełny tekst źródłaBeadle, Kendra A. "Chemical vapor deposition of tungsten carbide films on silicon and carbon substrates". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 55 p, 2007. http://proquest.umi.com/pqdweb?did=1338918711&sid=5&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Pełny tekst źródłaMeliani, Hasnaa. "Fonctionnalisation d'outils de décolletage de précision par micro-structuration de surface". Thesis, Bourgogne Franche-Comté, 2020. http://www.theses.fr/2020UBFCD022.
Pełny tekst źródłaTool wear is a major issue which compromises productivity and the ability of manufacturing high quality components. The main objective of this thesis is to improve the lifetime of coated or non-coated tools made of tungsten carbide and intended for stainless steel and aluminum machining. The functionalization method used in this work is surface structuring by femtosecond laser.At first, experimental study is conducted to investigate the interaction between femtosecond laser and tungsten carbide material. For the first time, all laser-matter parameters for generating ripples or athermal ablation structures on tungsten carbide is determined.Several structures at different dimensional scales are produced and tested on a closed-type tribometer. The purpose is to study tribological performances, both friction and wear, using structured surfaces in wet environment and to compare them to a reference surface. Wettability of structured surfaces is also measured and corresponding surface energies are determined.In the second experimental part, machining tests are conducted with various structured tools in orthogonal cutting and longitudinal turning configurations. A panel of structures is tested in order to identify the best geometrical structure which improves cutting tool performance.This study clearly shows the role of surface functionalization via femtosecond laser structuring in improving the lifetime of cutting tools by 30% in some cases
Kamdi, Zakiah. "Characterisation, wear and corrosion of tungsten carbide based HVOF and PTAW coating". Thesis, University of Nottingham, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659208.
Pełny tekst źródłaOliveira, Mark A. (Mark Anthony) 1977. "Slurry based Three Dimensional Printing (S-3DP tm) of tungsten carbide cobalt". Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/109638.
Pełny tekst źródłaDeshpande, Pranav K. "Wear Resistance and Electrical Property of Infrared Processed Copper/Tungsten Carbide Composites". University of Cincinnati / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1147536455.
Pełny tekst źródłaWentzel, Eduard John. "Erosion-corrosion resistance of tungsten carbide hard metals with different binder compositions". Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/18212.
Pełny tekst źródłaSabor, Said. "Contribution à l'étude quantique du carbure de tungstène neutre (WC) et ionisé (WCq+, q=1, 2)". Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1066/document.
Pełny tekst źródłaMetal carbides and oxides are more interesting in catalytic and industrial domains. Tungsten carbide WC has been detected as serious substituent of platinum Pt catalytic. The ultimate goal of this thesis is theoretical studies of electronic structure, stability and the bound nature on WC, WO and its cations. Our preliminary research were motiving by the available spectroscopic data on W, W+, W2+, WC et WC2+. We used the methodology (CASSCF/MRCI/MRCI+Q/aug-cc-pV5Z(-PP)) implemented on MOLPRO package to perform quantum calculations with high accuracy taking into account the correlation and relativistic effects with a specific treatment of spin orbit coupling for some low lying excited electronic states of WCn+, (n=0, 1 et 2). Our results are shown in good agreement with those available in the literature. Furthermore, in this work for the first time we demonstrated that a carbide dication (WC2+) is thermodynamically stable
Ren, Qiao. "Tungsten carbides as anode electrocatalyst of direct methanol fuel cell". Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 97 p, 2007. http://proquest.umi.com/pqdweb?did=1400426011&sid=12&Fmt=2&clientId=8331&RQT=309&VName=PQD.
Pełny tekst źródłaPrincipal faculty advisors: Jingguang G. Chen, Dept. of Chemical Engineering; and Thomas P. Beebe, Jr., Dept. of Chemistry & Biochemistry. Includes bibliographical references.
Papy, Kévin. "Compréhension et maîtrise de la mise en oeuvre des cermets par procédé de fusion laser sur lit de poudre pour la réalisation de pièces anti-usure". Electronic Thesis or Diss., Ecully, Ecole centrale de Lyon, 2023. http://www.theses.fr/2023ECDL0025.
Pełny tekst źródłaTechnogenia® is a French company, founded in 1979, specialized in hardfacing solutions based on tungsten carbide welding overlays. As part of the thesis, Technogenia® wishes to assess the suitability of using Additive Manufacturing technology to produce wear-resistant parts based on tungsten carbide. The company's primary objective is to use laser-powder bed fusion (L-PBF) technology to produce tungsten carbide-based parts that approach the mechanical characteristics of tungsten carbide-based parts made by conventional processes. The aim of this thesis is to study the feasibility of producing tungsten carbide-based parts, and to characterize the microstructures and mechanical and wear properties of parts produced by Additive Manufacturing. The properties of materials obtained using the L-PBF process will be compared with the known properties of parts produced by conventional processes. Firstly, two tungsten carbide-based powders with metal binders (cemented carbides) are selected for parametric optimization in the L-PBF process. This step is carried out by analyzing the influence of the main process parameters (laser power, scanning speed, scanning strategy, vector deviation, layer thickness, etc.) on the materials. An experimental design is defined in several steps, such as the production of beads, surfaces and cubes, in order to determine the main parameters. Two types of thermal post-treatment are carried out to study the influence on the materials and to eliminate certain structural defects. Microstructural differences between the two binders are analyzed and studied. Numerous phenomena due to the laser process are observed and commented on during sample analysis. Secondly, the samples successfully manufactured are subjected to mechanical and tribological characterization. Various mechanical tests (hardness, toughness, impact strength) are carried out to characterize and compare L-PBF materials with a reference material produced by conventional methods
Woolmore, Nicola J. "The failure of a tungsten carbide-cobalt cored projectile penetrating a hard target". Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4657.
Pełny tekst źródłaWoolmore, N. J. "The failure of a tungsten carbide-cobalt cored projectile penetrating a hard target". Thesis, Engineering Systems Department, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/4657.
Pełny tekst źródłaBretzler, Patrick [Verfasser]. "Tungsten Carbide as Alternative for Precious Metal Based Hydrogenation- and Electrocatalysts / Patrick Bretzler". München : Verlag Dr. Hut, 2020. http://d-nb.info/1219476544/34.
Pełny tekst źródłaOlivier, Andrew John. "Novel carbene complexes with pyrrole ligands". Diss., Pretoria : [s.n, 2001. http://upetd.up.ac.za/thesis/available/etd-02242006-125303/.
Pełny tekst źródłaMarou, Alzouma Ousseini. "Durabilité tribologique de matériaux pour insert de dents de tunnelier". Thesis, Ecully, Ecole centrale de Lyon, 2015. http://www.theses.fr/2015ECDL0042.
Pełny tekst źródłaThe frequency of maintenance operations during the excavation of the ground by the tunnel boring machines (TBM) is problematic for civil engineering companies. These maintenance operations provoke expensive timeouts and they bring in excavation operators in risky hyperbaric work conditions. One of the reasons which leads to the numerous human interventions for the maintenance is the damage of drag bits located on the cutting wheel of the TBM. These drag bits undergo wear due to the abrasiveness of the various media they meet. The purpose of this thesis is to contribute to increase by 20 % at least the lifetime of the materials of the dag bits, in order to reduce the various maintenance operations which expose the operators to important risks. To achieve this goal, the investigations led in this work concerned several axes. At first, an expertise is led to identify the wear modes prevailing on the carbide inserts located on the drag bits; then, new materials with enhanced mechanical properties and optimized microstructures, developed in the framework of the European project NeTTUN, are characterized on representative lab testing devices. These tests allowed us to understand well the wear mechanisms of the newly developed grades of tungsten carbides. The results of this work can lead to new strategies for the selection of materials to reinforce the drag bits
Stewart, David. "Studies on the abrasive wear behaviour of HVOF WC-Co coatings". Thesis, University of Nottingham, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287076.
Pełny tekst źródłaPretorius, René. "Fischer and N-heterocyclic carbene complexes of tungsten(0)". Diss., University of Pretoria, 2012. http://hdl.handle.net/2263/31515.
Pełny tekst źródłaDissertation (MSc)--University of Pretoria, 2012.
Chemistry
MSc
Unrestricted
Abioye, Taiwo E. "Laser deposition of Inconel 625/tungsten carbide composite coatings by powder and wire feedstock". Thesis, University of Nottingham, 2014. http://eprints.nottingham.ac.uk/14253/.
Pełny tekst źródłaCook, Grant O. III. "Joining Polycrystalline Cubic Boron Nitride and Tungsten Carbide by Partial Transient Liquid Phase Bonding". BYU ScholarsArchive, 2010. https://scholarsarchive.byu.edu/etd/2366.
Pełny tekst źródłaTrueman, Anthony Roger. "Characterization and corrosion studies of high carbon tool steel/tungsten carbide metal matrix composites". Thesis, Queensland University of Technology, 1999.
Znajdź pełny tekst źródłaArcher, M., RI McCrindle i ER Rohwer. "Analysis of cobalt, tantalum, titanium, vanadium and chromium in tungsten carbide by inductively coupled plasma-optical emission spectrometry". The Royal Society of Chemistry, 2003. http://encore.tut.ac.za/iii/cpro/DigitalItemViewPage.external?sp=1001953.
Pełny tekst źródła