Microstructure and Tribological Properties of CrN Films Deposited by Direct Current Magnetron Sputtering

CrN films were deposited on 304 stainless steel by DC reactive magnetron sputtering. The effects of nitrogen flow on the microstructure, mechanical and tribological properties were characterized by X-ray diffraction, scanning electron microscopy, atom force microscope, microhardness, wear tester and Nanomap 500LS profile. The results show that with the increase of nitrogen flow, the CrN films exhibit a preferential orientation in the (200) direction. The deposition rate of CrN films decreases with the increase of nitrogen flow. Besides, the surface roughness decreases first and then increases with further increase of nitrogen flow. As nitrogen flow increases from 15 cm³/min to 30 cm³/min, microhardness HV is improved from 5273 MPa to 10422 MPa, and then decreases to 9180 MPa when the nitrogen flow further increases to 35 cm³/min. Wear test results show that the CrN films deposited at nitrogen flow of 30 cm³/min achieve minimum friction coefficient value of 0.93 and wear rate 2.02×10⁻¹⁵ m³·(N·m)⁻¹, which present best wear resistance performance.