Die-casting aluminum alloy electroplating pretreatment process

Abstract

The invention relates to the technical field of metal surface treatment, and particularly relates to a die-casting aluminum alloy electroplating pretreatment process. According to the die-casting aluminum alloy electroplating pretreatment process, activation treatment is adopted to replace traditional procedures such as primary zinc precipitation, zinc removal, secondary zinc precipitation and alkaline chemical nickel precipitation, the technological process is simplified, the production efficiency is improved, wastewater discharge is greatly reduced, the raw material cost is saved, the equipment investment is reduced, and the labor cost is reduced; and in addition, phosphorus discharge is reduced through the descaling process, and the process is more environmentally friendly. Due to the fact that the plating time of an activating solution is short, the raw material consumption is low, the change of a bath solution is slow, the cost is low, a die-casting aluminum alloy piece subjectedto activation treatment has good adhesive force, and a good foundation is laid for the electroplating procedure; and in addition, the surface activity of a product plated with the activating solutionis high, and plating is started in a chemical nickel bath for 1-2 seconds after activation.

Description

technical field [0001] The invention relates to the technical field of metal surface treatment, in particular to a pre-treatment process for die-casting aluminum alloy electroplating. Background technique [0002] In general, die-casting aluminum alloys will add a certain amount of elements such as Si, Cu, Mg and Fe during die-casting in order to avoid pores, increase hardness and enhance ductility and other properties during molding. Die-casting aluminum alloys containing these elements are pre-plated with ordinary degreasing, alkali corrosion, descaling, primary zinc precipitation, zinc stripping, secondary zinc precipitation and other electroplating pretreatment processes, and then electroless nickel is electroplated. Wherein, both the primary zinc precipitation and the secondary zinc precipitation are placed in a zincate solution with a concentration of 100 g / L for a certain period of time. [0003] However, the die-casting aluminum alloy parts treated with the above-me...

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Problems solved by technology

[0003] However, the die-casting aluminum alloy parts treated with the above-mentioned zinc-precipitating solution have poor adhesion, which affects the subsequent electroplating process, and the traditional zinc-precipitating process will dissolve in some electroplating solutions due to the soft zinc layer, and will add more after zinc-precipitating. Upper alkaline chemical nickel process

Therefore, the die-casting aluminum alloy electroplating pretreatment process in the prior art has many procedures and uses many raw materials, and the cost of electroplating raw materials for aluminum parts is high, resulting in large equipment investment, high labor costs, and low work efficiency. There are a lot of baths to be controlled, and the amount of waste water is large, so the phenomenon of out-of-control baths frequently occurs, resulting in poor electroplating bonding

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