Study on electrolyte composition for surface improvement during ECH of turned titanium alloy

摘要

Electrochemical honing (ECH) is an ideal choice to machine hard passive materials such as titanium alloys for aerospace applications. Researchers have found electrochemical machining of titanium alloys as difficult because of huge amount of oxide film formation. The ECH process with conventional honing tool scrubs the passivating electrolytic metal oxide microfilm from higher work-profile area to allow clean surface for electrolysis. The selection and composition of electrolytes are key input factors to achieve better results during ECH. The present study focuses on the effect of NaCl and KBr mixture electrolyte on surface finish of turned titanium alloy Ti-6Al-4V. Experimental studies have been conducted with varying percentage composition of NaCl and KBr. It is found that in a 10% mixture electrolyte, 75% NaCl with 25% KBr is optimum for achieving surface finish in nano-scale with improvement in average surface roughness by 86% and maximum height of the profile decrease by 56%.