How to improve the adhesion during electroplating of aluminum alloy die-cast parts?
Aluminum alloys are chemically active and thus prone to oxidation and corrosion under natural conditions. To enhance their corrosion and oxidation resistance, a layer of metal is often electroplated onto the surface of aluminum alloy die-cast parts. The adhesion between the aluminum alloy and the electroplated metal directly affects the plating quality. Therefore, improving this adhesion is key to achieving better electroplating results.
1. Overview of Adhesion in Aluminum Alloy Die-Cast Parts
Due to their excellent plasticity, aluminum alloys can be die-cast into ideal shapes to meet customer requirements, which reduces the need for further processing and improves production efficiency. As a result, aluminum alloy die-cast parts are widely used in component manufacturing. To improve their atmospheric corrosion resistance and enhance decorative appearance, surface treatments like electroplating are often required.
Identifying the factors affecting adhesion during the electroplating process and implementing preventive or corrective measures is crucial for improving the plating pass rate and ensuring product quality.
2. Influence of Electroplating Processes on Coating Adhesion
Many factors determine the adhesion strength of electroplated coatings on aluminum alloy die-cast parts. Based on the experience of technical personnel, two main factors have the greatest impact on electroplating adhesion: pre-treatment and pre-plating processes.
The general electroplating process for aluminum alloy die-cast parts includes the following steps:
Chemical degreasing → Hot water rinse → Cold water rinse → Base layer plating → Cold water rinse → Activation treatment (optional) → Pre-plating → Cold water rinse (followed by intermediate or surface plating layers as needed)
Although every step in the electroplating process affects the overall plating quality to some extent, pre-treatment and pre-plating are the most critical steps in determining whether a strong and durable coating can be achieved.