Surface Modification by Electro-discharge Coating and Its Characterisation

Abstract

Applications of coated surface are swiftly increasing in present industrial context. Recently, the electro-discharge route is being explored for surface modification in terms of alloying and layer deposition. Electro-discharge machining parameters and response to surface deposition is of the research interest in electro-discharge coating. In this regard, electro-discharged surface modifications have been characterized in the present investigations. The effect of relevant EDM parameters (current, Pulse duration, duty factor, density of electrode material) on various surface alloying responses such as surface micro hardness, chemical composition of the alloying surface, surface deposition layer thickness has been studied. The EDM electrode is specially made of tungsten powder by semi-sintering process. Negative or reverse polarity is used for better results of layer deposition of electrode material of tungsten powder and carbon particles within the dielectric liquid used for machining. Considering ample of general applications in engineering, work piece is of low carbon steel/HSS has been identified. It is observed that tungsten carbide layer has been deposited on the work piece which shows better functional characteristics for the applications. Low to medium current (2–5 A), Low density of electrode material (7.15–8.03 kg/cm³) and low duty factor (3–5) are favorable conditions for better deposition of the layer.