Characterization of carburized layer on T8 steel fabricated by cathodic plasma electrolysis

A cathodic plasma electrolysis method was employed to fabricate a diamond-like carbon (DLC)-containing carburized layer on T8 carbon steel. The carburized layer was analyzed by scanning electron microscopy (SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Its tribological property was measured by the ball-disk friction and wear tester, and its corrosion behavior was evaluated by electrochemical method. The carburized layer contains the martensite, retained austenite and Fe3C phases. Plasma discharge reduces the activation energy of carbon diffusion into steel to 132.8 kJ · mol− 1 and increases the diffusion coefficient of carbon to 1.39 × 10− 7 cm2 · s− 1. Meanwhile, plasma discharge on the T8 steel in glycerol electrolyte enhances the formation of DLC component. The sp3 C content for DLC component is up to 67.6%. Moreover, both the wear resistance and corrosion resistance of treated steel are improved.