Technical Casting Process Of Zinc-aluminum Alloy Parts

Another feature of the zinc-aluminum alloy die casting process is that it has the advantages of fast production speed and high tensile strength. There are many reasons for the blistering of zinc-aluminum alloy die castings during the electroplating process, such as poor pre-plating treatment, the plating solution contains organic impurities and oil, the plating solution is contaminated by hexavalent chromium, and the base metal is poor. However, the blistering problem encountered in the production process was not mentioned in all the materials.

First, use a knife to scratch the blistering electroplated parts in the inner cavity. It was found that the bond between copper and copper was poor. It was suspected that the pre-plating process was improper and the plating layer was too thin. Therefore, the concentrations of alkali copper and copper pyrophosphate are both within the normal process range. The electroplating time of alkaline copper and copper pyrophosphate are all prolonged by 1 times. After electroplating is completed, the problem of inner cavity blistering still exists.

Analysis of zinc-aluminum alloy parts, zinc-aluminum alloy parts are die-casted, and then the plated parts are electroplated in alkaline copper for 30 minutes (thickness 10.2μm), directly into the acid copper, the result is no blistering in the inner cavity, so it is suspected to be copper pyrophosphate plating Slot reason. It was treated with hydrogen peroxide. When adding hydrogen peroxide, a yellowish-brown foam was found, and the operator was asked. The operator said *In the recent period of time, copper pyrophosphate and potassium pyrophosphate were added and then the hydrogen peroxide was added with yellow-brown foam; and It used to be milky white foam. According to phenomenon analysis, it may be the cause of copper pyrophosphate or potassium pyrophosphate.