Reciprocating two-body abrasive wear behavior of DC magnetron sputtered Mo-based coatings on hard-chrome plated AISI 316 stainless steel

The aim of this work was to study the influence of a hard chrome (HC) intermediate layer on the reciprocating abrasive wear behaviour of Mo-based coatings deposited by DC magnetron sputtering on AISI 316 stainless steel. The two-body abrasive wear characteristics of sputtered MoN, MoC and MoCN coatings on AISI 316 stainless steel with an electroplated HC layer were systematically evaluated using test a reciprocating pin-on-flat whose geometry is similar to that of ASTM G133-05 standard, but in this case, the pin was covered with SiC abrasive paper. Data showed that MoN coating had a lower wear rate than either MoC or MoCN coatings. The presence of plated HC on the stainless steel substrate considerably improved the wear resistance of all Mo-based coatings, presumably because of enhanced composite hardness and improved surface quality. One-way analysis of variance and multiple comparisons confirmed that MoN-HC and MoC-HC exhibited statistically insignificant differences in the wear rate, which were considerably lower than those of the other coating combinations. In addition, microstructural analyses suggested that the wear mechanisms for Mo-based coating in the absence of HC involved mainly plowing, cutting and oxidative abrasive wear processes while the wear processes of Mo-coatings on HC were mostly governed by cutting, fragmentation and fatigue wear processes.