The electropolishing process is initiated by immersing a metal part into a temperature-controlled bath of electrolyte (typically a mixture of sulfuric acid and phosphoric acid).

The working part is positively charged to act as the anode and is submerged in the solution along with negatively charged cathodes. A direct electrical current is then applied to the solution that causes minute fragments of the material to pull away from the workpiece as they are dissolved into the electrolyte solution—leaving behind a clean, smoothed surface.

Afterward, the parts are subjected to multiple rinsing steps to ensure any residual electrolyte is removed before the parts are dried and shipped out.

Whats the Difference between electropolishing and passivation?