Synthesis of wear resistant compounds by plasma diffusion process

Abstract

Thermal resistant compound layers have been synthesized on hot working tool steel (H13) through the duplex process by combining metal ion plating and nitrogen plasma diffusion at elevated temperatures of 550–950 °C. Ti and Al layers were deposited by the cathodic arc ion plating process in three different modes which were Ti single layer, Ti/Al and Ti/Al/Ti and then subsequent nitrogen plasma diffusion treatment with intense plasma heating through hollow cathode discharge effect. Plasma diffusion of Ti and Al films on the steel substrate in the temperature range 550–950 °C produced nitride compounds of TiN and Ti 2AlN as well as various intermetallic compounds of Fe 3Al and Fe 2Ti at the surface and interface region. The formation of mixture compounds highly enhanced surface hardness up to 2800 HK (0.25 N). High temperature wear resistance also greatly increased in the temperature range 300–600 °C due to the layer formation of thermal resistant compounds. Compound formation features and high temperature wear behaviors are analyzed using XRD, EDS, and microstructural observation.