Coulometric and Ellipsometric Measurements of Passive Film Thickness on Zinc Electrodes in  KOH  Solution

Abstract

Manual null ellipsometry and double potential‐step chronocoulometry were used to estimate the passive film thickness on zinc electrodes in solutions. Measurements were conducted over a range of temperatures, hydroxide concentrations, and potentials. To check mass transport effects, several rotation rates were used in the chronocoulometric experiments. Estimated thicknesses vary with the operating parameters but are in general of the order of 500Å. Film thickness values determined by the two methods generally showed agreement within the experimental uncertainty.