- Sep 19, 2018 -
An aluminum or aluminum alloy product is used as an anode, placed in an electrolyte solution for electrification treatment, and a process of forming an aluminum oxide film on the surface by electrolysis is called anodizing treatment of aluminum and aluminum alloy. After anodizing, the aluminum surface can form an oxide film of several micrometers - several hundred micrometers. Compared with the natural oxide film of aluminum alloy, its corrosion resistance, wear resistance and decorative property are obviously improved and improved. The principle of aluminum anodization is essentially the principle of water electrolysis. When the current passes, the following reactions will occur: On the cathode, H2 is released as follows: 2H + + 2e → H2 On the anode, 4OH - 4e → 2H2O + O2, the oxygen evolved is not only molecular oxygen (O2), but also atomic oxygen (O), and ionic oxygen (O-2), usually expressed as molecular oxygen in the reaction. . The aluminum as the anode is oxidized by the oxygen deposited on it to form a water-free Al2O3 film: 2A1 + 3[O] = A12O3 + 1675.7KJ It should be noted that the generated oxygen does not all react with aluminum, and some of it is precipitated in a gaseous form.