Double glow plasma surface alloying and plasma nitriding

Based on plasma nitriding technique, Double Glow Plasma Surface Alloying Technology (DG Technique) was developed in 1980. This technique breaks the restriction of traditional plasma nitriding and successfully applies solid alloying elements, such as Ni, Cr, W, Mo, Ti, Al, Nb et al., to realize plasma surface alloying. Numerous experiment results concerning the DG technique have demonstrated that various alloys and alloy steels, such as high speed steel, nickel base alloy and wear resistant alloys et al., have been produced upon the surfaces of carbon steels, titanium alloys, Ti–Al intermetallic compounds and copper.This paper is written in hope that the differences between plasma nitriding and DG technique will become more apparent. Some new development and experiment results of the double glow plasma surface alloying are also shown in this paper. For example, Ti–Al–Nb–C alloy has been produced on the surface of TiAl and Ti–Cu and Ti–Cr burn-resistant alloys have been formed on the surfaces of titanium and Ti6Al4V alloy by using this process; When solid graphite is used as carbon supplier, hydrogen-free carburizing has been carried out in order to avoid hydrogen embrittlement of titanium materials; Co–W–Mo–Fe age hardened high speed steel has been produced on the surfaces of carbon steels.