Surface treatment solution for die-casting aluminum alloy electroplating
June
www.xy-global.com
2022-02-23 18:33:53
The content of Si in the die-casting aluminum alloy is 6.5% to 7.5%, and the high Si content makes the material have good fluidity during the die-casting process. Die-casting aluminum has light weight, good mechanical strength, electrical conductivity, good thermal conductivity, non-magnetic, and can use die-casting technology to cast complex parts with high dimensional accuracy. However, the adhesion of the die-cast aluminum alloy electroplating layer is poor, and the corrosion resistance needs to be improved. From the perspective of cost and function, electroplating color zinc and chromate treatment can be considered.
1. Die-casting aluminum alloy surface electroplating color zinc
Aluminum itself is an amphoteric metal, which is unstable in acid or alkaline solutions. In addition, the die-cast aluminum alloy itself has a loose structure, and there are defects such as blisters and pores, which often affect the quality of electroplating. After proper pretreatment, the electro-galvanizing of die-casting parts becomes easy. Electroplating a zinc layer of about 10um and then passivation treatment can double the corrosion resistance of die-casting aluminum alloy. In order to prevent the color zinc from discoloring, dip coating An organic protective film.
2. Die-cast aluminum alloy surface with chromate treatment
After the die-casting aluminum alloy is sandblasted, it can be directly treated with chromate, so that a passivation film can be obtained on the surface. This film can be colorless to yellow according to needs, and does not affect the surface resistance. In order to achieve the three-proof of the product If required, it can be sprayed after chromate treatment.
