Parametric study on surface modification of Al-7075 alloy using electric discharge coating

This work investigates the surface modification of Al-7075 alloy using a copper-multi-walled carbon nanotube powder metallurgical green compact tool in the electric discharge coating process. The effect of input parameters such as compact load, peak current ( I p ), and pulse on-time ( T on ) on material deposition rate and surface roughness ( R a ) has been investigated. The process parameters are optimised using the teaching learning-based optimisation algorithm. Maximum material deposition rate of 0.62 mg/min with minimum R a of 3.00 µm has been achieved at compact load of 6 tons, I p of 2.5 A, and T on of 1000 µs. The field emission scanning electron microscopy images show smooth surface generation at low I p and compact load settings. Characterisation using different techniques confirms the presence of tool materials on the modified surface. The microhardness test of the modified surface exhibits a higher hardness value of 2.70 times than that of the substrate material.