The Anodic Oxidation of Nickel in 1N H 2 SO 4 Solution

Abstract

The anodic oxidation of nickel in solution has been studied employing potentiostatic and galvanostatic techniques. It has been found that although a large amount of charge is consumed during anodic oxidation, only about 5% of this charge is involved in film growth. The thickness of the passive film on nickel in is between 6–16Å for anodic oxidation times of 15–60 min. The experimental results have been used to develop a kinetic equation describing the film growth on nickel. It is shown that the logarithm of the film growth current density is inversely proportional to the charge stored in the film. The resistivity of the film suggests that the film is pure and almost stoichiometric . It is suggested that the Flade potential of nickel in corresponds to that potential, more noble than the passivation potential, at which the surface of the nickel is covered with a pore‐free film of and passivation is complete.