抄録
Dyeing affinity, CR value and properties of the anodized films on aluminum produced in alkaline solutions (0.1M-NaF, 0.1M-NaOH, 0.1M-Na2CO3, 0.1M-Na3PO4 and NH4OH-NH4F baths) at low temperature (0°C) have been investigated and compared with those produced at room temperature (20°C). Anodized films produced at low temperature showed a higher corrosin resistance, scratch hardness and better wear resistance than the films produced in room temperature baths except for dyeing affinity. A thick film and high CR value were obtained in NH4OH-NH4F bath at low temperaure, and the CR value was about double of the anodized film produced in room temperature bath. In the case of dyeing affinity, anodized films produced in low temperature baths were inferior to the films produced at room temperature. The films produced in NH4OH-NH4F bath or NH4F bath had very high hardness and better wear resistance compared with films produced in other alkaline baths. The film formed in Na3PO4 had very high corrosion resistance. It was considered from these results that the high corrosion resistance was caused by precipitation of aluminum fluoride or phosphate on the surface and in pores.
