アルミニウムアノード酸化皮膜の細孔電解機構について

抄録

A modified explanation of the mechanism of metal deposition on the porous anodic oxide film of aluminum separated from the substrate is proposed as a result of measuring anion effect of the catholyte, membrane potential and ionic permeability. A concentration cell, Cu/CuSO₄ (0.1mol)/oxide film/CuSO₄ (x mol)/Cu was constructed and its EMF was measured by a potentiometer. Oxalic acid film manifested very low asymmetrical potential which well responded against the ionic concentration, whereas sulfuric acid film showed very high asymmetrical potential with less reproducibility. By utilizing tracer technique, diffusion and migration velocity of sulfate ion was determined. From these results, Cu²⁺ ion is supposed to be permeable to the pores of the oxide film. When insoluble copper salts are precipitated in the pores, diffusion and migration of Cu²⁺ ion are surpressed and bath voltage rises introducing a high bipolar in the pores. This might be interpreted by the fact that the metallic deposit occurred at the anolyte side of the oxide film. Once the metallic deposit has begun in the pores, further metallic deposit is able to continue by the electronic conduction of the metal itself.