抄録
This paper describes the effects of addition of oxidizing agents (KMnO4, NH4VO3, K2Cr2O7, K2S2O8, H2O2, and K3Fe(CN)6) on AC electrolysis of aluminum in alkaline solutions.
The thickest and hardest film was obtained in 0.1mol NaOH solution containing 0.05mol of KMnO4.
A bright black film was obtained in the alkaline solution of 0.225mol NaOH containing K3Fe(CN)6 and K2Cr2O7.
The optimum conditions were as follows.
pH: 11-12
Current density: 0.8-1amp./dm2
Electrolysis time: 0.5hrs.
Corrosion resistance of the black film was higher than that of anodized film (alumite) in H2SO4. Fe, Cr, and Al were found in the film by qualitative analysis.
