Improvement of Corrosion and Wear Resistance of CoCrNiSi(0.3) Medium-Entropy Alloy by Sputtering CrN Film

In this study, Co, Cr, and Ni were selected as the equal-atomic medium entropy alloy (MEA) systems, and Si was added to form CoCrNiSi(0.3) MEA. In order to further improve its wear and corrosion properties, CrN film was sputtered on the surface. In addition, to enhance the adhesion between the soft CoCrNiSi(0.3) substrate and the super-hard CrN film, a Cr buffer layer was pre-sputtered on the CoCrNiSi(0.3) substrate. The experimental results show that the CrN film exhibits a columnar grain structure, and the film growth rate is about 2.022 μm/h. With the increase of sputtering time, the increase in CrN film thickness, and the refinement of columnar grains, the wear and corrosion resistance improves. Among all CoCrNiSi(0.3) MEAs without and with CrN films prepared in this study, the CoCrNiSi(0.3) MEA with 3 h-sputtered CrN film has the lowest wear rate of 2.249 × 10(−5) mm(3)·m(−1)·N(−1), and the best corrosion resistance of I(corr) 19.37 μA·cm(–2) and R(p) 705.85 Ω·cm(2).