Composition Determination of NiCo Alloys by the RRDE Method

A technique that makes use of a rotating ring‐disk electrode has been developed for the composition determination of alloys. Because of its low cost and ease of use, the technique is ideally suited for the study of plating solutions. Following deposition on the rotating disk electrode, the alloy is dissolved in a stripping solution design in such a way that ring detection of the Co2+ product of the disk reaction becomes possible. The stripping solution contains a complexant for Co (1,10‐phenanthroline) and an agent (Na‐thiosulfate) that helps prevent passivation of Ni‐rich alloys. A parametric study has been conducted to arrive at optimal conditions for the performance of the stripping experiments. Good agreement between RRDE and an independent method for alloy composition determination has been obtained.