Influence of Process Parameters on the Adhesive Strength of CrN Coatings

In order to enhance the corrosion and wear resistance of the STVAX alloy, the CrN film has been deposited by UBM(unbalanced magnetron) sputtering. In this study, the influence of process parameters, such as N2 gas concentration and Cr interlayer insertion, on the adhesive strength was investigated. By increasing the concentration of N2 gas from 30% to 33%, the microstructure of the coating layer was changed from hexagonal Cr2N to cubic CrN. By increasing N2 gas concentration to 38%, a CrN coating layer with a preferred orientation of plane was formed. Nanoindentation testing showed that the mechanical properties of coatings varied according to the coating type and crystallographic orientation. Superior adhesive strength was obtained at the of N2 gas concentration of 38%, and higher hardness at 33% concentration. The adhesive strength of the coating film was higher with a Cr interlayer than that without. These findings showed that the Cr interlayer between the CrN coating and the STAVAX substrate significantly improved the adhesive strength of coating to the substrate.