Synthesis of Electrical Discharge Metal Matrix Composite Coating Through Compacted Semi-Sintered Electrode and Its Tribological Studies

Abstract

Electric Discharge Coating an alternate process for surface modification/alloying/coating to improve the mechanical and metallurgical properties of the materials using conventional Electrical Discharge Machine. The compaction pressure of semi-sintered nickel and tungsten electrode influences the material migration together with substrate material and pyrolysis carbon results in metal matrix composition coating. In depended of pressure spark gap are stable increases the deposition of alloying materials lessens the formation carbon layer, cracks, voids, blowhole over the surface and made the layer to be metallurgical mixed composition surface that reduces the brittleness. This makes the layer four times higher in hardness value than the substrate material to 1100HV0.5 and reduction in specific wear to 0.082x10-5mm3/Nm depends on the inclusion of alloying material with carbon percentage consequences in self-lubricant properties that varies the wear rate. Surfaces topography obtained during alloying, material migration, mechanism is characterized through Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray spectroscopy (EDX)and wear through pin-on-disc tribometer