Effects of rare earths addition on the microstructure, wear and corrosion resistances of plasma nitrided 30CrMnSiA steel

► The RE addition in plasma nitriding is propitious to decrease the surface roughness. ► The RE addition doesn't change the type of phases, but increases the ε intensity. ► The hardness of the nitrided layer has a 100 HV0.1 increase by rare earths addition. ► The friction coefficient and wear rate of the layer nitrided with RE are lower than without RE. ► The corrosion resistance is improved by nitriding regardless of with or without RE.