1. First, do a good job of mechanical polishing by sand blasting or shot blasting, which is to obtain a high salt spray foundation. After polishing, there are few impurities on the surface of die-casting aluminum alloy, and a corrosion-resistant oxide layer is generated, which is beneficial to improve the corrosion resistance of the parts.
2. Secondly, do a good job of ash removal and acid cleaning activation treatment: a special activated ash removal agent can be used, which consists of agent A and agent B. When used, the A:B ratio is 1:2, and the treatment time is 3 seconds, so as to remove impurities such as oxides and polishing ash on the surface, thus obtaining a purified aluminum alloy surface.
3. final passivation treatment: soak or spray the treated die-cast aluminum alloy parts with passivation solutions SY-421 and SY-421B to deposit a dense and corrosion-resistant chemical oxide film on the aluminum alloy surface, thus achieving good corrosion resistance.