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

Abstract

The anodic oxidation of nickel in 1N H2SO4 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 1N H2SO4 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 normalNiO . It is suggested that the Flade potential of nickel in 1N H2SO4 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 normalNiO and passivation is complete.

The charge transfer kinetics of the oxidation of silver and nickel nanoparticles via particle–electrode impact electrochemistry

“…There are no oxidative features until the onset of anodic dissolution at +1.4 V (vs. SCE) which is consistent with the presence of the layer of surface NiO. The oxidation of NiO then occurs [19][20][21][22][23] forming the soluble NiO 2 . 24 Voltammetry conducted at a Ni rod (diameter 12 mm) is consistent with this, showing oxide formation followed by continuous dissolution at potentials above +1.5 V (vs. SCE) (Fig.…”

Comparative Potentiodynamic Study of Nickel in Still and Stirred Sulfuric Acid‐Potassium Sulfate Solutions in the 0.4–5.7 pH Range

“…The electrochemical studies on the active-passive transition of nickel in acid were also performed by applying nonstationary and impedance techniques (3,(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29). The voltammograms associated with the dissolution, prepassivation, and passivation of nickel in sulfuric acid exhibit at least two current peaks (I and II) located at potentials more positive than the equilibrium potential calculated for the NiO electrode (3,14,15,(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29).…”

A Point Defect Model for Anodic Passive Films: II . Chemical Breakdown and Pit Initiation

“…On the other hand, for small values for hV (but that are still larger than 0.05V), t is proportional to exp (--xF~hV/2RT). It is interesting to note that Heusler and Fischer (2) obtained an empirical equation for the relationship between t and aV of the form log t/to = Vo/~V [17] where to and Vo are constants.…”