An Ellipsometric Study of the Anodic Oxidation of Nickel in Neutral Electrolyte

Abstract

Ellipsometry is used to study alternate anodic and cathodic galvanostatic cycling of a nickel electrode in neutral sulfate and borate electrolyte. The removal of the electropolishing film under cathodic reduction, the anodic oxidation of the nickel substrate, and the deposition and conversion of films of and can all be distinguished clearly on a plot of the optical data. The mechanism of anodic oxidation of the substrate is investigated using both optical and open‐circuit transient measurements, and the field in the oxide film is concluded to limit the substrate oxidation process.