Diffusion and Solid Film Formation durin

This study investigates the electropolishing process of various metals using different electrolytes under potentiostatic conditions, focusing on current-time behavior across several orders of magnitude at varying temperatures. The research identifies three distinct stages during the electropolishing: firstly, a constant current density phase; secondly, a saturation stage where the current density decreases with the reciprocal square root of time, and finally, a steady-state current density phase described by an exponential time law. Theoretical models based on Elmore's work effectively describe stages I and II, while a novel model addressing convection effects is introduced for stage III. It posits that the formation of a solid film during the transition from stage I to II contributes to deviations from expected current-time behavior. Mathematical treatment of this phenomenon indicates film thickness ranging from 3 to 30 nm. This work builds upon previous contributions to the understanding of electropolishing, aiming to clarify the complex interactions between metal dissolution and film formation in anodic processes.