Electrochemical polishing of TC4 titanium alloy with passivation film protection

Distinguished from anisotropic electrochemical polishing, isotropic electrochemical polishing (IEP) belongs to a novel polishing technique with the advantages of high polishing efficiency and superior surface quality, which has made extensive use in the field of metal surface treatment. Here, this work firstly studied the effects of different parameters including processing temperature, current density, electrolyte composition and polishing time on the polishing effect of TC4 titanium alloy. The breakdown of passivation film formed on the surface and the uniform etching of metal inside etched holes constituted two basic steps of the IEP process. Adjusting viscosity or adding halogenated elements into electrolyte could enhance mechanical properties and surface quality of substrates after polishing. Based on different etching stages, suitable power parameters were selected to form segmented pulse regulation, thereby improving polishing quality as well as processing stability. The experimental results revealed the mechanism of IEP and its great potential for industrial application.