Experimental optimization of electrical discharge coatings using conventional electrode

Abstract

In the last few years, researchers around the world are working to develop procedures that will allow coating a conductive material on another conductive base material using Electrical Discharge Machine (EDM). This process helps to extend the usage of EDM for the purpose of hard coatings. In this study, 24 experiments were conducted to coat copper on titanium alloy substrate by varying the coating input process parameters and surface treatments and output responses such as material deposition rate (MDR) and electrode wear rate (EWR) were calculated. Wherever it is necessary, L9 orthogonal array design of experiments was implemented and all the coatings were taken for characterization with scanning electron microscope (SEM). With this characterization, surface morphology, coating thickness, coating-base material interface and surface crack density were studied to select one optimum coating for each case. Selected three coatings were considered for further characterization viz., phase analysis with X-ray diffraction (XRD) and surface topography with Atomic Force Microscopy (AFM). Phase obtained were Cu and TiZn16 which were further heat treated to stabilize. Line and area profiles from surface roughness analysis was obtained and parameters such as min and max, peak and valley, Ra, Rq, Rz were evaluated.