DEVELOPMENT OF STAINLESS ALUMINUM

A process for surface modification of Al-based materials is described which involves immersion in boiling Ce(NO3)3 and CeCl3, followed by anodic polarization in a molybdate solution. Each of these three steps is carried out for 2 h. Al 6061 treated in this manner did not show any signs of uniform or localized corrosion during immersion in 0.5N NaCl for 60 days. A sample with a scratch in the modified surface also did not show any corrosion after 25 days in NaCl. Since this surface modification process produces exceptional corrosion resistance, it should be considered as a candidate for the replacement of chromate conversion coatings.