Plasma duplex treatment influence on the tribological properties of the UNS S32760 stainless steel

Abstract

Super duplex stainless steels are widely used in harsh environments due to their high corrosion resistance. However, the improvement of their tribological properties can contribute to a better performance of these materials in service. In this regard, this study aimed to evaluate the application influence of duplex treatment on the tribological properties of the UNS S32760 super duplex stainless steel. Two treatment times, 2 h and 4 h, were studied for both the nitriding step and the cathodic cage plasma deposition step. The results showed that the combination of the nitrided layer and the TiN film, confirmed with the application of Rietveld refinement on the XRD data, contributes to the wear volume decrease by up to 9.41 times. This behaviour was associated with the increase in surface microhardness and the excellent adhesion conditions (HF1) presented by the film deposited over the nitrided layer. The film provided a change in the wear mechanism, evidenced by the reduction in the tendency to wear by scratches. Additionally, was observed the presence of lower oxygen content in the wear region of the treated samples, that can be associated a lower heating of the samples during the test. Thus, the duplex treatment has a great application potential for improving the wear resistance of UNS S32760 steel.