AlTiCrN coatings deposited by hybrid HIPIMS/DC magnetron co-sputtering

In this study, the AlTiCrN coatings with different Cr contents were deposited from AlTi and Cr targets using a hybrid coating process that combines high power impulse magnetron sputtering with DC magnetron sputtering. The microstructure and mechanical properties of the AlTiCrN coatings were investigated using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and nano-indentation. The tribological behaviors of the AlTiCrN coatings were evaluated by pin-on-disk tribo-tests at 400 °C, 600 °C and 800 °C, respectively. The results indicated that all the AlTiCrN coatings exhibited (Al,Ti,Cr)N solid solution phases with FCC NaCl-type structure. With increase in Cr target power, the Cr content increased from 0 to 25 at. %, tailoring changes in coating microstructure and properties. Firstly, the preferred orientation shifted from (111) to (200). Secondly, the hardness and elastic modulus of the AlTiCrN coatings increased from 31.4 ± 1.4 GPa and 448.8 ± 9.3 GPa at 0 at.% Cr to 33.7 ± 1.4 GPa and 469.5 ± 8.2 GPa at 8.9 at.% Cr, and then decreased with further increase in Cr content. Thirdly, the friction coefficient and wear rates of the coatings against Al2O3 balls also exhibited some relationship with the coating compositions and test temperatures. The inherent mechanism was analyzed and discussed.