Surface hardening of metallic alloys by electrospark deposition followed by plasma nitriding

This paper presents the results of a study concerned with the surface hardening of nonferrous and ferrous alloys, by integrating the electrospark deposition and plasma nitriding processes. Specimens of an aluminium bronze and of a grey cast iron were firstly electrospark coated with AISI-304 stainless steel and, then, ion nitrided in a 25%N2 + 75%H2 dc plasma. It is shown that by using these two treatments, the surface hardness of this two materials can be substantially increased.