Rapid anodizing technology replacing chromic acid for LY12CZ aluminum alloy

Aluminum alloy anodizing coatings were prepared for LY12CZ in 45 g/L sulfuric acid solution through adding organic acid additive and buffering agent for fast film-forming, with the gradient voltage of 15-25 V, to replace the traditional chromic acid anodizing and boric-sulfuric acid anodizing. The field emission scanning electron microscope, titrating test, coating mass test and fatigue test were used to evaluate the properties of the anodizing coatings. The results show that organic acid additive and buffering agent for fast film-forming can relieve the dissolution of anodizing coatings, improve the compactness and corrosion resistance and reduce the fatigue damage during the anodizing process. Moreover, the properties of coatings anodized in the new anodizing solution of sulfuric acid, organic acid and buffering agent with the voltage of 15 V for 5 min and of 25 V for 5 min are equal to ones anodized in boric-sulfuric acid with the voltage of 15 V for 20 min. Organic acid additive is YP additive and buffering agent for fast film-forming is YJ additive.