Al-Zn合金溶射皮膜の食塩水中における電気化学的挙動

抄録

The corrosion potential, polarization behavior and corrosion rate of Al, Al-78 and 85%Zn alloys and Zn sprayed films in a 3% NaCl solution were electrochemically examined at 25°C. The polarization characteristics were measured by means of potentiodynamic and potentiostatic methods. The corrosion rate was determined from the intersection of local anodic and cathodic polarization curves. The Al and Al-78%Zn alloy sprayed films have almost identical corrosion potentials, and the Zn and Al-85%Zn alloy sprayed films also do so. The anodic and cathodic polarization curves of the Al-Zn alloy sprayed films are similar to those of the Zn sprayed film. Zn in the alloy preferably dissolves in the anodic polarization process. Increase in polarizing current is retarded by oxide films formed on the surface of Al matrix. The estimated corrosion rates of Al, Al-78%Zn, Al-85%Zn and Zn sprayed films are about 2, 20, 16 and 26 μA/cm² respectively.