Surface property enhancement of Ni-free medical grade austenitic stainless steel by low-temperature plasma carburising

Based on the success of the feasibility study reported, the surface properties of low-temperature plasma carburised P558 Ni-free medical grade (ASTM F2581) austenitic stainless steel have been fully evaluated in terms of electrochemical corrosion, dry- and corrosion-wear and fretting-wear in Ringer's solution. Anodic polarization tests demonstrated that the precipitate-free S-phase generated by low-temperature plasma carburising at 500 °C for 15 h can retain the good corrosion resistance of the untreated ASTM F2581 Ni-Free material in Ringer's solution. The wear resistance of the Ni-free austenitic stainless steel can be improved by 700% and 140% when reciprocating against a WC ball in air (dry-wear) and in Ringer's solution (corrosion-wear) respectively. In addition, the low-temperature plasma carburising treatment can considerably reduce the friction coefficient and improve the fretting-wear resistance of the Ni-free austenitic stainless steel in Ringer's solution.