Thin amorphous alumina films were prepared on stainless steel, type AISI 304, by low pressure metal-organic chemical vapour deposition. The effect of thermal annealing in nitrogen (for 2, 4 and 17 h at 600, 700 and 800 °C) on the film properties, including the protection of the underlying substrate against high temperature corrosion and the chemical composition of the film, were investigated. Corrosion experiments performed at 450 °C in a hydrogen sulphide-containing gas, showed that the thermal annealing process had a detrimental effect on the protective properties of the alumina films. From FTIR and Auger measurements, it was found that the amorphous alumina, containing boehmite, converted to ¿-alumina during the annealing process.
Haanappel, V. A. C., Haanappel, V. A. C., van de Vendel, D., van Corbach, H. D., Fransen, T., & Gellings, P. J. (1995). The effect of thermal annealing on the properties of thin alumina films prepared by low pressure MOCVD. Thin solid films, 256(1-2), 8-12. https://doi.org/10.1016/0040-6090(95)80026-3