Codeposition of Nickel and α-alumina Particle from Watts Type Bath

The relation between the codeposition behavior of the particle and the pH shift near the cathode according to hydrogen evolution was studied. A Watts type bath with α-alumina particle was used for the investigation. In order to elucidate the effect of pH shift on the metal ion adsorption, potentiometric titration was performed. It was clarified that the pH plateau of the titration curve for nickel sulfate solution in the presence of α-alumina particle is less than the pH plateau of the titration curve without α-alumina particle. This means that nickel ion is fixed on the surface of the oxide nevertheless hydroxide production does not occur in the bulk, at a certain pH. In this condition, the fixed nickel ion on the particle is able to induce the codeposition of the particle.