Electropolishing of titanium grade-2 in hydrofluoric acid – ethylene glycol electrolyte

Electropolishing is a finishing process that selectively removes material from the surface of both simple or complex metal parts to produce a bright and smooth surface. In this study, the electropolishing process was applied to Titanium grade-2 material, known for its purity as alpha titanium and widespread utility, using an electrolyte composed of a mixture of hydrofluoric acid and ethylene glycol. The primary objective was to investigate the evolution of surface morphology through various analytical techniques such as surface roughness measurements, optical microscopy and scanning electron microscopy. The study delved into crucial parameters of the electropolishing process: current density, electrolyte temperature, electropolishing time, and initial surface roughness. Titanium grade-2 material demonstrated favorable electropolishing character in an electrolyte solution comprising 10.5 vol-% hydrofluoric acid and 89.5 vol-% ethylene glycol. Moreover, the study revealed that mechanical polishing, as a preparatory step, significantly influenced surface brightness, electropolishing duration and the lifetime of the electropolishing solution. The optimum surface finish for Titanium grade-2 was obtained at 20°C, with a current density of 22 A/dm 2 , over a duration of 12 minutes, within the parameter ranges covered in this study.