Abrasive wear of texture-controlled CVD α-Al2O3 coatings

In the present study the wear resistance of some CVD alpha-Al2O3 coatings with different growth textures, i.e. 0001, 101_2 and 101_4, and a kappa-Al2O3 coating have been investigated using a micro-abrasion test with diamond particles as the abrasive medium. The results show that the softer kappa-Al2O3 coating shows a higher wear rate as compared with the textured alpha-Al2O3 coatings. Of the latter coatings, the 101_4 textured alpha-Al2O3 coating shows the lowest wear rate while the 0001 and 101_2 textured alpha-Al2O3 coatings show similar wear rate. Two different dominant wear mechanisms, i.e. micro cutting and micro chipping, were observed and the latter mechanism is believed to control the wear rate of the Al2O3 coatings investigated. The results obtained are discussed in relation to the dominant wear mechanisms of the coatings identified using scanning electron microscopy.