Wear Behavior of TiAlN and CrAlN Coatings Deposited by TRD Process on AISI D2 Steel

The wear properties of uncoated, chromium aluminum nitride (CrAlN) and titanium aluminum nitride (TiAlN) coated AISI D2 steel were investigated and compared using ball-on-disc method at 0.3 m/s sliding speed and under the loads of 2.5 N, 5 N, and 10 N against $Si_3N_4$ ball as a counter material. Steel samples were nitrided at 575C for 8 h in the first step of the coating process, and then titanium aluminum nitride coating and chromium aluminum nitride were performed by thermoreactive deposition (TRD) process at 1000C for 2 h. Coated samples were characterized by X-ray diffraction analysis, scanning electron microscopy, microhardness, and ball on disk wear tests. The results of friction coefficient and wear rate of the tested materials showed that the TiAlN coating presents the lowest results.