P/M Turbo Charger and Armature Components: Plasma Nitriding and Nitrocarburizing to Reduce Friction Wear

Plasma nitriding of the 310 SS and plasma nitrocarburizing of the Fe-P PM low density materials were carried out using one- and the two-temperature step cycles. It was found that the plasma treatment significantly increased nanohardness of the samples and that this increase was higher for the materials subjected to the two-step cycle. Scratch test data showed the residual depth, penetration depth of the stylus and coefficient of friction being much smaller for the plasma treated samples than for the raw samples. It appeared that neither surface of the plasma treated 310 SS or Fe-P samples is under compressive stress.