Microstructures and tribological behaviour of oxynitrided austenitic stainless steel

This study investigates the microstructures and tribological behaviour in the modified layers of AISI 304 steel produced by active screen plasma oxynitriding. Compositional analysis of modified layers was carried out by field emission scanning electron microscopy, atomic force microscopy and high-resolution transmission electron microscopy. The results demonstrated that the modified composite duplex layer consisted of an amorphous and nanocrystalline oxynitrided layer (upper layer) and the nitrided layer (lower layer). Additionally, the wear resistance of the active screen plasma oxynitrided specimens was much higher than that of the untreated ones. The wear rate of the treated specimen decreased by approximately 95% compared with that of the untreated one. The analysis of the worn surface indicated that the treated specimen exhibited slight oxidation and abrasive wear, whereas the untreated one showed severe adhesive wear and plastic deformation.