Tribological and mechanical properties of physical vapor deposited alpha alumina thin film coating

Alpha alumina thin film coatings were deposited by Alternating Current inverted magnetron sputtering technique. 1 micron thick coatings were deposited on silicon at 3 different power levels (4, 5 and 6 kW) and 3 different oxygen partial pressure ratios (40, 50 and 60% by volume) for studying the tribological properties such as adhesion, hardness, wear resistance, coefficient of friction, and wear rate. Maximum critical load of 30 N was obtained by scratch test. Hardness was measured as 20 GPa. The coating with 5 kW and 50% oxygen partial pressure ratio showed the best wear resistance and coefficient of friction properties. The wear behavior of alpha alumina at different sliding distance was studied.