Wear and corrosion properties of nanocrystalline coatings on stainless steel produced by plasma electrolytic nitrocarburizing

Abstract

Abstract Plasma nitrocarburizing was applied to AISI 316L stainless steel substrates using an electrolytic plasma technique, based on a dielectric barrier discharge created during cathodic saturation in an aqueous electrolyte. The samples were biased cathodically with a direct current high voltage. The wear resistance of the treated samples was evaluated using a pin-on-disk wear testing method. Results indicate that the resultant hardened nitrocarburized layers exhibited excellent abrasive wear resistance. Investigation of the wear characteristics showed that the magnitude of weight loss and the wear mechanisms strongly followed from the treatment experimental parameters. Additionally, in order to evaluate the corrosion properties of the layers a potentiodynamic polarization test was performed on the hardened samples. Results indicated that short time as well as high treatment temperature provided a slight increase in corrosion resistance while in the case of long treatment time the corrosion resistance decreased. These changes in the properties could be attributed to the different nanocrystalline morphologies of the nitrocarburized layers.