Plasma nitriding of Fe-Cr-Mo sintered steels

Plasma nitriding was applied to Fe-Cr-Mo and Fe-Cr-Mo-C alloys with different Cr content and microstructure. Chromium allows a hard and controlled diffusion layer to be obtained, almost independent of the microstructure. Interesting results in terms of wear resistance and impact resistance were obtained by nitriding the as sintered carbon alloyed material. Analogous results were obtained by conventional quenching and stress relieving. The two treatments may constitute alternative solutions for the production of sintered components subjected to contact Hertzian stresses or fatigue.