Corrosion and tribo-corrosion behavior of a-SiCx:H, a-SiNx:H and a-SiCxNy:H coatings on SS301 substrate

Amorphous hydrogenated silicon carbide (a-SiCx:H), silicon nitride (a-SiNx:H) and silicon carbonitride (a-SiCxNy:H) coatings were prepared by plasma enhanced chemical vapor deposition (PECVD) and investigated as attractive candidates for corrosion and tribo-corrosion enhancement of stainless steel 301 (SS301). The deposition process has first been optimized in order to obtain the best mechanical properties. All coatings prepared under such optimized conditions exhibited significantly enhanced tribological behavior. They substantially improved the wear resistance of the SS301 substrate, while reducing the wear rate by a factor of ~ 47, 33 and 15, for a-SiCx:H, a-SiNx:H and a-SiCxNy:H coatings, respectively. Corrosion tests in 1% NaCl solution revealed that the coated samples possessed substantially better corrosion resistance than the bare substrate. Specifically, the a-SiCx:H coating exhibited the highest corrosion resistance, with a corrosion current (icorr) of 7.4 × 10− 12 A/cm2, compared to 2.5 × 10− 8 A/cm2 for the bare SS301 substrate. It was observed that the a-SiCxNy:H coating performed very differently under dry and wet tribological conditions. We show that the combination of high wear and corrosion resistance for the a-SiCx:H coating results in its superior performance in tribo-corrosion test, making it a particularly attractive candidate for the applications in which wear and corrosion act simultaneously.