Low-temperature plasma surface modification of medical grade austenitic stainless steel to combat wear and corrosion

The novel low temperature plasma alloying technique that simultaneously introduces both nitrogen and carbon into the surface of austenitic stainless steel has been used in the past to create a hybrid N-C S-Phase. This S-Phase layer boasts of high hardness and wear resistance without any detriment to corrosion resistance. In this study, the afore mentioned hybrid N-C S-Phase was successfully implemented in the surface of two medical grade austenitic stainless steels: ASTM F138 and F1586. At an optimum process temperature of 430 degrees C a very hard, 20 mu m precipitate-free S-Phase layer was created. Anodic Polarization tests in Ringer's solution showed that the corrosion resistance of this layer was similar to that of the untreated alloys. Both dry-wear and corrosion-wear (Ringer's) behaviour of the surface treated alloys showed an improvement of more than 350% and 40% respectively when compared to the untreated material.