Temperature effect on the kinetic alumina layer growth on 5086 aluminum substrate

Abstract

To achieve desired porous structure for specific applications, the film growth kinetics and nanostructure can be largely controlled by well monitoring anodization parameters. The pores distribution and dimensions can be significantly affected by the electrolyte nature, the applied voltage and the anodization temperature which seem to be one of the major parameters. In the present work, all spec-imens anodized with the same starting courant density value of 1.4 A were analyzed. The effects of Low (LT) and room (RT) temperatures on hard anodizing layers were studied qualitatively and quantitatively. At room tempera-ture, the total current is maintained at high levels due to large reduction current that slows the growth of the oxide layer. For low temperature, the current decreases more rapidly against anodizing time which leads to thick alumi-na layer with high mechanical properties. The best results of anodized layer hardness both, on the surface and at the profile section were observed at 120 min anodizing time; beyond this time, the thickness increases up to 140 μm for 5 h but with lower proprieties due to porosity.