Hardness and Contact Angle of CrN Coating Sputtered on Matrix of S136 Stainless Steels

CrN coating was prepared on the surface of different S136 stainless steels by sputtering. By means of contact angle measurement, hardness testing, scanning electron microscopy (SEM) and X-ray diffraction (XRD), effects of parameters such as microstructure, orientation, surface roughness, machining process and sputtering bias on the contact angle and hardness of CrN coating were studied. The experimental results indicate that single phase Cr2N coating with the preferred orientation of (111) plane was obtained by sputtering under conditions of 300 W, -120 V bias when the flow ratio of argon to nitrogen was 9∶1. The surface hardness and contact angle of S136 stainless steels were significantly improved after CrN sputtering. The contact angle of CrN coating sputtered with bias voltage was obviously larger than that without bias voltage. The longitudinal direction samples with less impurities and fine carbides, polished after grinded and sputtered with bias voltage, had higher hardness (1 177 HV) and larger contact angle (98.77°) after CrN sputtering.