How to electroplate aluminum and aluminum alloys?
ã€China Aluminum Industry Network】Aluminum and aluminum alloys can significantly improve the physical or chemical properties of the surface after they have been plated with various metals. When aluminum and aluminum alloys are used as conductors, electroplating of silver on the surface can increase the surface or electrical contact area. Conductivity; In order to facilitate the welding of aluminum, the surface of the copper is electroplated with copper, nickel or tin; in order to improve its wear resistance, a thick layer is electroplated on its surface. In terms of decorativeness, electroplating enamel is mostly used.
The electroplating of aluminum and aluminum alloy surfaces has been tried and used for practical production long ago. However, there are oxides between aluminum and aluminum alloy and the coating. The thermal expansion coefficient of aluminum and aluminum alloy and metal coating are different. The coating has pinholes and residual plating solution and other factors, resulting in poor adhesion of the coating. When used for a long time, it will peel off or even be plated. Immediately after peeling off, in the field of surface treatment, the electroplating process of aluminum and aluminum alloys is still in the exploratory stage. There has been no substantial breakthrough for a long time, and there has been no perfect and mature process. The incompatibility of plating is the quality of aluminum and aluminum alloy plating and product qualification rate is still an industry bottleneck.
Conventional aluminum and aluminum alloy plating process
Aluminum and aluminum alloy plating process consists of three parts: pre-plating, electroplating, and post-plating. Pre-plating treatment is a relatively key process related to the quality of electroplated products. Its main purpose is to remove the grease on the surface of aluminum and aluminum alloys, naturally forming oxide films and other contaminants.
The conventional general process flow is: degreasing-washing-demineralization-washing-pickling-washing-activation-washing-primary zincation-washing-dezincification-washing-secondary zincation-washing-neutral nickel-plating-washing- Subsequent plating.
There is also a wave of anodized film instead of zinc immersion process in the subsequent plating.
Improved general-purpose aluminum and aluminum alloy plating pretreatment process
Degreasing alkaline etching 2-in-water-pickling-washing-ashing-washing-alkaline activation-zinc-leaching-washing-neutral nickel-plating-washing-subsequent electroplating.
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