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Visar resultat 1 - 5 av 36 avhandlingar som matchar ovanstående sökkriterier.

  1. 1. Microfabrication of Tungsten, Molybdenum and Tungsten Carbide Rods by Laser-Assisted CVD

    Författare :Kajsa Björklund; Tamas Szörényi; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Laser-assisted CVD; tungsten; molybdenum; tungsten carbide; kinetics; field emission; nanocrystalline; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

    Sammanfattning : Thin 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. LÄS MER

  3. 2. Aqueous Processing of WC-Co Powders Aqueous processing of WC-Co powders

    Författare :Karin Andersson; KTH; []
    Nyckelord :Hard metal; cemented carbide; WC-Co; tungsten oxide; tungsten carbide; oxidation; cobalt; dissolution; surface complexation; XPS; AFM; colloidal probe; force curve; Hamaker constant; Cauchy; WO3; CoOOH; CoO; Co3O4; ESCA; zeta-potential; surface poten;

    Sammanfattning : The object of this work is toobtain a fundamental understanding of the principal issuesconcerning the handling of WC-Co powders, in an aqueousmedium.The oxidation and dissolution oftungsten carbide powder dispersed in water was investigatedusing X-ray Photoelectron Spectroscopy (XPS) and leachingstudies. LÄS MER

  4. 3. Cemented Carbide Sintering : Constitutive Relations and Microstructural Evolution

    Författare :Anders Petersson; KTH; []
    Nyckelord :Cemented carbides; Sintering; Constitutive relations; Microstructure; Densification; Modelling;

    Sammanfattning : Cemented carbides based on tungsten carbide and cobalt arecommonly produced by a powder metallurgy route including liquidphase sintering. The pressed compact densifies to almost halfits volume during sintering due to pore elimination. LÄS MER

  5. 4. Aqueous Processing of WC-Co Powders

    Författare :Karin M. Andersson; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Hard Metal; Cemented Carbide; WC-Co; Tungsten Carbide; Cobalt; Oxidation; Dissolution; Surface Complexation; XPS; AFM; Colloidal Probe; Hamaker Constant; Cauchy; WO3; CoOOH; ESCA; Zeta-Potential; Surface Potential; Poly ethylene imine ; PEI; Suspensi;

    Sammanfattning : The object of this work is to obtain a fundamentalunderstanding of the principal issues concerning the handlingof an aqueous WC-Co powder suspension.The WO3 surface layer on the oxidised tungsten carbidepowder dissolves at pH>3 with the tungsten concentrationincreasing linearly with time. LÄS MER

  7. 5. Vapor phase deposition of WO and WC

    Författare :Per Tägtström; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; vapor deposition; ALE; CVD; tungsten oxide; epitaxy; nanocrystals; tungsten carbide; Kemi; Chemistry; Kemi; Inorganic Chemistry; oorganisk kemi;

    Sammanfattning : WO3 and WC are two compounds that are widely used for a number of different thin film applications. In this thesis, these compounds have been deposited using two different deposition methods: atomic layer epitaxy (ALE) and chemical vapor deposition (CVD). LÄS MER