Preparation and characterization of Ca-containing anodic alumina

Ca-containing anodic alumina (CAA) has been successfully prepared by anodizing Al film in an alkali solution at a constant voltage and subsequently electro-depositing calcium salts on and into anodic alumina. This paper investigated the anodic behavior of Al, deposition behavior of calcium salt, and microstructure of CAA. The results show that the anodic behavior of Al in Na₃PO₄ electrolyte can be described as three continuous stages as of initial growth of the compact barrier layer, formation of porous alumina and further development of its pores and columnar holes. It is also found that cell voltage of electro-deposition process plays an important role at the deposition behavior of calcium slat and the microstructure of Ca-containing anodic alumina (CAA). The higher the cell voltage is, the faster the deposition rate, and the more calcium being deposited at the surface of anodic alumina and into the columnar holes or at the walls of the holes of anodic alumina. It is expected that Ca-containing anodic alumina films are promising substrates for fabricating functional bio-coatings for prosthetic applications.