PLASMA-DIFFUSION TREATMENT AND DUPLEX TREATMENT RECENT DEVELOPMENT AND NEW APPLICATIONS

Plasma diffusion treatment (PDT) is one of the most promising methods for improving both the surface and the near-surface properties. The du plex treatment combining the plasma diffusion with PVD or PACVD provid es an excellent method for achieving optimal properties of the surface and the near surface and allows the design of a layer system to meet the increased demands of functional surfaces. In the present review, r ecent investigations of the plasma diffusion treatment of ferrous and non-ferrous materials are reported. For austenitic steel, Ti alloys, C o base alloys and Cr coating, plasma diffusion treatment has been carr ied out. In the case of austenitic steel, processes are optimized to a chieve improved wear resistance, retaining the excellent corrosion res istance of the steel. While the wear resistance and the friction prope rties were mainly of interest for stellite 6B, in addition the corrosi on resistance has been investigated for Cr coating on steels after pla sma diffusion treatment. The Ti alloy TiA16V4 showing a gradient layer system after plasma nitriding has been duplex treated by adopting PAC VD. The microstructure, wear and friction as well as corrosion behavio ur have been investigated and the results of biocompatibility testing are presented briefly.