SYNTHESIS OF WEAR-RESISTANT COMPOUNDS BY PLASMA-DIFFUSION PROCESS

Thermal resistant compound layers have been synthesized on hot working tool steel (H13) through the duplex process by combining metal ion pl ating and nitrogen plasma diffusion at elevated temperatures of 550-95 0 degrees C. Ti and Al layers were deposited by the cathodic are ion p lating process in three different modes which were Ti single layer, Ti /Al and Ti/Al/Ti and then subsequent nitrogen plasma diffusion treatme nt with intense plasma heating through hollow cathode discharge effect . Plasma diffusion of Ti and Al films on the steel substrate in the te mperature range 550-950 degrees C produced nitride compounds of TiN an d Ti2AlN as well as various intermetallic compounds of Fe3Al and Fe2Ti at the surface and interface region. The formation of mixture compoun ds highly enhanced surface hardness up to 2800 HK (0.25 N). High tempe rature wear resistance also greatly increased in the temperature range 300-600 degrees C due to the layer formation of thermal resistant com pounds. Compound formation features and high temperature wear behavior s are analyzed using XRD, EDS, and microstructural observation.