Plasma nitriding and nitrocarburising of sintered Fe-Cr-Mo and Fe-Cr-Mo-C alloys

The effect of plasma nitriding and nitrocarburising on the microstructure, and the microhardness and the wear resistance of two sintered alloys, Fe-Cr -Mo and Fe-Cr-Mo-C, was studied. Nitrocarburising improves the microhardnes s profile and the wear resistance of the C-free material with respect to ni triding, while it does not induce any appreciable improvement with respect to the nitrided C-alloyed material. The wear resistance of the nitrocarburi sed C-free material is the same as that of the nitrided C-alloyed material. Nitrocarburising tends to induce the grain boundary precipitation of carbo nitrides in the diffusion layer. (C) 2001 Elsevier Science B.V. All rights reserved.