Wear behavior of annealed atomic layer deposited alumina

Atomic layer deposited (ALD) alumina is a promising candidate for use as a wear-resistant and protective coating in MEMS and other applications. While the tribological properties of ALD alumina may be affected by numerous factors related to processing, environment, and operating conditions, its wear behavior is neither quantified nor well understood. In this study, ALD alumina is annealed at different temperatures, then subjected to sliding wear testing in a humid air environment. Tribological properties appear to be heavily influenced by annealing temperature. Surprisingly, the wear rate decreased by about two orders of magnitude after annealing at 1000 ⁰C for 1 hour. This improvement in wear resistance was shown to be influenced by the formation of crystalline phases as annealing temperature increased.