Why does aluminum alloy die casting not rust

The anodized film of aluminum has high hardness, good corrosion resistance and wear resistance, and has good transparency, so that the surface after anodizing treatment maintains the original metal texture of aluminum. However, the combination of aluminum alloy die-casting materials with this very multi-metallic material will easily produce gas lines, cold insulation, sand holes and other defects during the surface treatment of aluminum alloy die-casting parts. Because the second phase generated by alloying elements is different from the electrode potential of the aluminum matrix Therefore, the anodic oxidation behavior and mechanism of aluminum alloy are much more complicated than pure aluminum. At the same time, the composition of aluminum alloy anodic oxide film is not only aluminum oxide and anions in solution, but also some alloying elements in aluminum alloy. , oxide state or intermetallic compound state exists. Therefore, the appearance quality of the aluminum alloy die-casting oxidation treatment is poor, and the defect rate is high.

It is a difficult problem to do anodizing in the existing process of aluminum alloy die-casting, but the electroplating of aluminum alloy die-casting products can be done under the condition of reasonable structure. Generally, a layer of zinc is first plated, then a copper bottom is plated, and then electroplating.