“Tungsten carbide is known for its refractory properties and high hardness values and is used in the cutting tools industry in the form of coatings on iron, steel and other metals. In the present study, tungsten carbide films were deposited on iron substrates by plasma enhanced chemical vapor deposition, using tungsten hexacarbonyl precursor. The substrate-film interaction and the effect of substrate temperature and post-deposition annealing on film composition were studied. The substrate temperatures used were 225°C and room temperature. Annealing was done at 800°C for 4 hours. Films were analyzed before and after annealing for elemental atomic percentages and chemical composition using Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction. Thickness was determined by SEM and AES.
Analysis of samples deposited on a 225°C substrate indicated the presence of very small crystallites of tungsten oxide and carbide phases before annealing. On annealing, intermixing of the iron substrate and the film was noted and ascribed to the apparent diffusion of iron from the substrate into the film during annealing. The X-ray diffraction patterns and the AES and XPS results indicate the presence of ternary W, Fe and C compounds in the film. The film is a mixture of more than one phase with the prominent phases being Fe3W3C and W-rich tungsten carbide. Room temperature depositions also yield a ternary phase after annealing, however tungsten carbide is the dominant phase there and not the ternary compound. Preliminary results indicate that similar phenomena occur for deposition on cobalt as well at 225°C, with and without annealing”--Abstract, page iii.
Morosoff, Nicholas C.
James, William Joseph
Rosen, Stephen L.
Chemical and Biochemical Engineering
M.S. in Chemical Engineering
University of Missouri--Rolla
x, 52 pages
© 2002 Narayan Vaidyanathan, All rights reserved.
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Plasma-enhanced chemical vapor deposition
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Vaidyanathan, Narayan, "Plasma enhanced chemical vapor depsoition of tungsten carbide films on iron" (2002). Masters Theses. 2232.
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