Formation mechanism of porous structure on 316L stainless steel by anodization

The micro-pores with size of 0.2 to 1.8 μm, which randomly distribute in a 316L stainless steel substrate, were fabricated by the transfer of the porous structure of anodic porous alumina. The mask anodic porous alumina was directly prepared by anodizing of aluminum film, which was deposited on 316L substrate by DC magnetron sputtering. The transfer of the porous structure of anodic alumina into the 316L substrate could be achieved without the additional through-hole treatment to the barrier layer. The localized priority dissolution on porous alumina is observed during the anodizing. And this process is considered to lead to the micro-pores formation on 316L substrate. In addition, the effect of anodizing time on the pores size and number on 316L substrate also was discussed.