Influence of pretreatment on surface behavior of duplex plasma treated AISI H13 tool steel

The purpose of duplex surface engineering involves a sequential application of two surface technologies in order to develop a surface with combined properties. Duplex treatments consisting of plasma nitriding (PN) and physical vapor deposition (PVD) have been proven to be successful in improving wear, corrosion resistance and the load-carrying capability of steel substrates. In the present study, an attempt has been made to investigate the role of pretreatment on initial surface condition on duplex treated surface properties after PN in three different time durations 6, 12, and 24 h, followed by PVD coating on as-received and heat treated AISI H13 tool steel. After duplex treatment, samples were characterized by XRD and SEM. Surface roughness was evaluated by the surface profilometer, microhardness by Vickers microhardness tester and wear resistance properties by tribometer. Surface roughness and hardness values are higher for heat treated conditions compared to the as-received conditions in three different time durations. It has been observed that the initial surface condition and thickness of the white compound layer, play important roles in governing the final properties of the coating material. Wear resistance is also better in heat treated condition for duplex treated samples compared to the as-received condition.