抄録
Anodizing of aluminum is widely applied for many aluminum products to improve the corrosion and wear resistances. It is well known that cracks in anodic oxide films occur at relatively sharp corners of aluminum parts. These cracks at the corners promote the corrosion of aluminum products. In order to prevent the formation of the cracks, it is generally recommended that the sharp corners of aluminum parts should be changed to round corners.
In this paper, the formation of the cracks in the anodic oxide films at the corners of aluminum parts was theoretically analyzed using FR value defined in this paper as the film formation ratio ; and then two theoretical equations were derived. One equation gives the angles of the cracks at the sharp corners of aluminum parts, and the other equation gives the critical radius of the occurrence of the cracking in anodic oxide films at the round corners of aluminum parts. Experimental results revealed that the theoretical angles of the cracks in the anodic oxide films at the sharp corners agreed with the experimental ones, and that the critical radius of the crack formation at the round corners calculated by the theoretical equation agreed with the experimental ones using the value of elongation ratio, P=0.003.
