Characterisation of TiC layers deposited using an electrical discharge coating process

Electrical discharge machining (EDM) is a non-conventional, high-accuracy machining process for the manufacture of complex shapes, regardless of hardness of the workpiece. There is interest to develop the EDM technique for coating or surface modification by using a powder metallurgy (PM) tool electrode and/or added powder suspended within the dielectric fluid. We report on the EDM deposition of TiC coatings onto stainless steel, using either Cu or TiC electrodes, with and without Ti powder in the working oil. EDM processed layers exhibited hardness values similar to 3-4 times higher than the substrate, emphasising the ability of EDM to impart improved mechanical performance to the surface of austenitic stainless steel.