Microstructure and mechanical properties of Cr–Ni–N coatings deposited by HiPIMS

Abstract

Cr–Ni–N coatings, the Ni content of which was altered from 0 to 6·3 at-%, were deposited by a hybrid coating system consisting of high power impulse magnetron sputtering and radio frequency magnetron sputtering. The effects of Ni addition to Cr-N coatings on the microstructure and mechanical properties of the coatings were investigated in this study. The instrumental analysis revealed that the Ni element was incorporated into Cr-N crystals as solid solutions, while excess Ni was precipitated as nanocrystalline phases at the Cr-N grain boundaries. The toughness of the Cr–Ni–N coatings was significantly improved with Ni content increased. In addition, the hardness of the coatings slightly increased from 30·4 to 32·6 GPa due to the grain refinement effect and solid solution hardening. From the tribological tests, the highest wear resistance was obtained from the sample having a Ni content of 2·7 at-%.