CHEMICAL VAPOR DEPOSITION OF POLYCRYSTALLINE ALUMINUM OXIDE.
ARMY MATERIALS AND MECHANICS RESEARCH CENTER WATERTOWN MASS
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Polycrystalline aluminum oxide was chemically vapor deposited onto sintered alumina substrates by reaction of AlCl3 with H2O, CO2 O2, and O2 at temperatures of 1000 C and 1500 C, and pressures of 0.5 and 5.0 Torr. While the thermodynamics of all three reactions predict the formation of solid Al2O3, the deposition rate of the first reaction was considerably greater than that of the second. The third reaction was so slow that no measurable deposit was formed in six hours at 1500 C. Formation of dense deposits of the alpha-Al2O3 was favored by increasing temperature and decreasing pressure. Microstructural examination of the dense deposits showed long columnar grains, the largest of which extended through the deposit from the substrate to the surface. Authors
- Manufacturing and Industrial Engineering and Control of Production Systems