How to improve the bonding strength of aluminum alloy die castings during electroplating?
Aluminum alloy is easy to be oxidized and corroded under natural conditions because of its active chemical properties. In order to improve the corrosion resistance and oxidation resistance of aluminum alloy die castings, we often coat the surface of aluminum alloy die castings with metal. The combination of aluminum alloy die casting and electroplating metal determines the effect of electroplating. Therefore, improving the bonding force between aluminum alloy die casting and electroplated metal has become an important factor to improve the electroplating effect.
How to improve the adhesion of aluminum alloy die castings
Summary of 1 aluminum alloy die casting adhesion
Because of its good plasticity, aluminum alloy can be die-casted according to customer requirements to achieve an ideal structure, reduce the follow-up processing links, that is, high production efficiency, so that aluminum alloy die casting has been widely used in parts manufacturing. In order to improve its corrosion resistance in the atmosphere and other decorative properties to meet the requirements of its use, it is often necessary to carry out surface treatment such as electroplating.
From the periodic table, we know that the elements of aluminum alloy are lively. Therefore, the chemical stability of aluminum alloy in acid and alkali medium is poor, so the electroplating on aluminum alloy die casting is much more difficult than that on other metals such as steel, copper and copper alloy. It is easy to cause the defects of poor adhesion such as blistering and shedding of the coating caused by over-corrosion of the base metal. This is also the main reason for producing waste and modified products in aluminum alloy electroplating. Therefore, it is an important way to improve the qualified rate of zinc alloy die castings and ensure the quality of products by pulling out the factors affecting the zinc alloy electroplating cohesion from the electroplating process and taking corresponding preventive measures.
Influence of electroplating process on adhesion of 2 aluminum alloy
There are many reasons for determining the adhesion of aluminum alloy diecasting coating. According to the experience of Hongyuan aluminium alloy die-casting and electroplating technician in Shenzhen Xin Ning, it is found that there are two main factors affecting the adhesion of aluminium alloy die-casting and electroplating, namely, pretreatment and pre-plating process.
The electroplating process for aluminum alloy die castings is usually carried out as follows:
Chemical cleaning degreasing hot water washing cold water washing plating bottom cold water washing activation treatment (some do not carry out) pre-plating cold water washing (as required by the process intermediate or surface layer, below)
In the whole process of aluminum alloy die-casting electroplating, although each process has different degrees of influence on the quality of electroplating, pretreatment and pre-plating process are the primary and key factors to determine whether a good coating adhesion can be obtained.
