Low adhesion effect of novel duplex NC/WC:C coatings against ductile materials at elevated temperatures

A novel anti-adhesive NC/WC:C surface processing is presented enabling green machining of ductile materials at elevated temperatures. The duplex coatings are produced by the active screen plasma nitrocarburising followed by physical vapour WC:C deposition. Microstructure analysis showed that duplex NC/WC:C system is composed by a nanolayered low adhesive WC:C coating and an extra load-bearing NC hardened case, obtaining favourable frictional properties at elevated temperatures. The coefficient of friction of duplex coating NC/WC:C was significantly lower compared to sole WC:C coating or untreated surfaces, and as demonstrated, depending on the testing temperature non-linearly, including an ultra-low adhesion at 350 °C. Furthermore, the quantified adhesion rate is clearly correlated with the nanomechanical properties especially the elastic parameters.