Fe, Ni合金電着とその共析機構に及ぼす陰極近傍のpH変化

抄録

A study has been made experimentally and theoretically to clear the relation between the anomalous codeposition of Ni-Fe and the pH change near the cathode. The pH change was measured with Sb microelectrode. The Dahms' equation was applied to estimate the pH change for the solutions containing Fe²⁺ or Ni²⁺. Partial polarization curves for Fe and Ni depositions and H₂ evolution were also obtained by the aid of an atomic absorption spectrometry of the deposits. As a result, it was found that the equation is valid in the solution containing Fe²⁺ or Ni²⁺, and that the anomalous codeposition occurres only when the pH near the cathode rises up to neutral region. In the case of anomalous codeposition, the nickel depositing potential shifted towards negative by more than 100mV, while that of iron shifted towards positive by 100-200mV.