Plasma Nitrocarburizing of AISI 316L Austenitic Stainless Steel Applying a Carbon Active Screen: Status and Perspectives

Abstract

AbstractPlasma nitrocarburizing of austenitic stainless steel at 420 °C is typically applied to improve the surface hardness and wear resistance without impairing the corrosion resistance of the material. Recently, based on the active screen technology a novel plasma assisted approach has been developed substituting the usually used steel active screen by carbon-fibre reinforced carbon. This new concept avoids the use of carbon containing feed gases and provides highly reactive process gases consisting predominantly of unsaturated hydrocarbons and CN-radicals. The feasibility of this novel approach has been proven by spectroscopic and metallurgical studies in smaller laboratory set-ups but also in industrial scale systems. The present contribution compiles recent achievements in active screen plasma nitrocarburizing of AISI 316L and related materials using a carbon active screen under variations of bias power and process gas composition. The results are compared to plasma nitrocarburizing treatments using an active screen made of steel.