Aluminum oxide coating on nickel substrate by metal organic chemical vapor deposition

Aluminum oxide thin films were coated onto nickel substrates via chemical vapor deposition. The aluminum oxide was produced by pyrolysis of a metal acetylacetonate precursor. This reaction was done at relatively low temperatures, from 435 to 550 °C to deposit a thin film of aluminum oxide. The coating provided protection against isothermal oxidation at elevated temperatures. Resistance to oxidation was obtained for all of the coated substrates. Surface morphology, however, changed when heated for prolonged time. Samples coated at 500 and 550 °C are effective up to 900 °C whereas samples coated at 435 °C were good up to 800 °C. The metal oxide compositions and phases were studied by X-ray diffraction and EDAX. The surface properties of the deposited thin films were investigated with scanning electron microscopy.