Deposition of α-alumina Via Combustion Chemical Vapor Deposition
Combustion chemical vapor deposition was used to synthesize α-alumina thin films. The deposition solutions were 0.0015 M aluminum acetylacetonate dissolved in isopropanol. Fused silica and nichrome (Ni–20Cr) served as substrates. Deposition temperatures were in the range of 1050 °C to 1125 °C.
Crystalline films consisting of hexagonal α-grains were produced on both substrates. Some films on nichrome displayed preferred orientations of (113) and (116) normal to substrate surfaces, while films deposited on silica showed no preferred orientation. Films deposited on nichrome seemed denser than those on silica as the grains clustered together to provide a ‘cauliflower’ appearance.
The oxidation response of uncoated and alumina-coated nichrome specimens was measured by isothermal thermogravimetric analysis in pure flowing air at 900 °C, 1000 °C and 1100 °C. The coated specimens had significantly lower mass gain values and parabolic rate constants than their uncoated counterparts.
Kelekanjeri, V. Siva Kumar G.; Carter, W. B.; and Hampikian, J. M.. (2006). "Deposition of α-alumina Via Combustion Chemical Vapor Deposition". Thin Solid Films, 515(4), 1905-1911.