Preparation and property evaluation of NbC coating deposited on 316L stainless steel

The work aims to investigate the corrosion resistance and blood compatibility of NbC as biological inert coatings in simulated body fluids, so as to provide a reference for improving the performance of 316L stainless steel as a cardiac stent. NbC coating was prepared by the physical vapor deposition (PVD) widely used in surface modification area and the coating properties were improved by optimized process to obtain high adhesion force and density. Scanning electron microscope (SEM), Atomic force microscope (AFM), X-Ray diffraction (XRD), Nano-indentation and Scratch test were used to investigate the microstructure and mechanical properties. The potentiodynamic polarization curve and platelet adhesion test were used to characterize the corrosion resistance and evaluate hemocompatibility of NbC coatings. With the increasing of substrate temperature, the mechanical properties, corrosion resistance and blood compatibility of NbC coatings were significantly improved, and the hardness and elastic modulus of NbC coatings increased from (12.5±0.2) GPa and (213±0.8) GPa to (24.5±0.4) GPa and (275±1.1) GPa, respectively. The self-corrosion rate was significantly optimized from 8.76×10-6 A/cm2 to 1.98×10-8 A/cm2. In general, the NbC coating has the same stability as 316L stainless steel in simulated body fluids, but the corrosion rate is much lower than that of 316L stainless steel. The platelet adhesion behavior of NbC coating is significantly improved, which is expected to be an inert coating to improve the surface performance of naked 316L stainless steel. © 2019, Chongqing Wujiu Periodicals Press. All rights reserved.