How is the hole of silver plating screw in aluminum alloy cavity turning green? It is a die-casting product.

Hello, this kind of situation you mentioned often happens in electroplating. There are several reasons, please refer to. 1. Generally, copper hydride or copper sulfate will be plated before silver plating, which may not be completely dried after being soaked in liquid medicine, especially a small amount of liquid medicine will remain in screw holes and some Chacon. 2. The screw holes of this aluminum alloy die-casting product are all post-processed, and some lubricants may be used during the processing, resulting in residues that make the silver plating worse.