New Technology for Electroless Nickel Plating on Aluminum Alloy Wheels

The direct electroless nickel activators for aluminum and aluminum alloys are non-toxic, odorless, non-polluting, and special green environmental friendly new products developed at home and abroad after years of research and development. Compared with the traditional zinc deposition process, it reduces pollution emissions, reduces product costs, and improves the rate of one-off plating.

1Advantages of Direct Electroless Nickel Plating with Special Activators

1.1 Eliminating the secondary zinc-invasion replacement process, simplifying technology management, bath management, and wastewater treatment.

1.1.1 After the workpiece is activated by special activators, it can be electroplated with nickel or flash electroless nickel plating only once or without washing, eliminating the complicated secondary zinc replacement process, reducing the production process and increasing the production efficiency. Makes technology management, bath management, and wastewater treatment simple.

1.1.2 The use of special activators for direct electroless nickel plating requires only 7 processes to complete the entire work. The use of zinc sinkers for secondary zinc dip treatment requires 17 processes to complete the electroplating of nickel.

1.2 uniform and dense plating, strong bonding, good quality plating

1.2.1 Direct electroless nickel plating with special activator, because there is no effect of electric current, the plating capacity is very strong, no hole can not penetrate, and the small pinhole and slag hole can be plated completely, and all the parts where the activator penetrates are Plating, so that the activated aluminum wheel die-casting aluminum material as smooth as the steel parts deposited on the surface of a layer of bright, dense, good adhesion of electroless nickel plating layer, dense coating, plating quality is good.

1.2.2 Overcome the electrolyte is easily affected by the harmful impurities in the secondary zinc dipping solution, contaminate the electroless nickel plating solution, the coating quality cannot be kept stable, the operation procedure is complicated, the technical difficulty is great, and the electroless nickel plating solution needs to be adjusted and replaced frequently. All the deficiencies.

Plating and matrix bonding force: A356 die-cast aluminum alloy was used as the test piece. After electroless nickel plating, the workpiece was heated to 200° C. in an oven and kept at a constant temperature for 2 hours. Then, it was quenched several times in water at room temperature. No blistering was found on the coating. The boring knife method, saw blade method and tape method test are all superior to the secondary zinc leaching process.

1.3 The high one-time pass rate greatly reduces product costs.

1.3.1 Secondary zinc deposition method The low potential area in the aluminum hub caused by segregation and enrichment of the grain boundary of the die-casting material is susceptible to plating and blistering, and the one-time pass rate has been fluctuated around 80%, and some are even lower.

1.3.2 After deplating the aluminum wheel, polishing and replating nickel will increase the cost greatly. According to investigations, the cost of aluminum wheels that are electroplated with nickel after deplating is three times higher than the cost of a one-time qualified aluminum wheel. After secondary electrochemical nickel plating, the aluminum wheel blank must be scrapped if it fails. Some aluminum wheel companies fail because of one-time pass rate is too low. Some electroless nickel-plated aluminum wheels were qualified at the time of testing, but they were blistering after being stored in warehouses for some time. . Some of them are blisters after the product is sent to a more end-user for a certain period of time. The reason is that in a corrosive environment with a corrosive atmosphere, when the corrosive atmosphere reaches the substrate through pinholes and other defects in the surface layer, the zinc displacement layer is opposite. When the plated metal and the aluminum substrate become anodes, the zinc will be subject to lateral corrosion, and a white powdery substance will appear between the aluminum hub substrate and the plated layer. This will eventually cause problems of blistering and peeling of the plated layer.

1.3.3 Electrochemical nickel plating using special activators directly enables the aluminum wheel hub to have a one-time pass rate of more than 98%. There is basically no waste, which greatly improves the quality of the aluminum wheel hub and reduces the product cost. It also solved the problem of the low qualification rate of gravity cast aluminum wheel blanks.

2 operating specifications:

2.1 The special activator is applicable to electroless nickel plating rolling and hanging plating production lines of various aluminum alloy die castings.

2.2 How to use:

1. Activator 20%

2. Temperature 30°C—50°C (PRD can be used at room temperature without heating)

3. Time 1-3 minutes

4.PH value 9-11

2.3 Activator maintenance: The direct electroless nickel activator for aluminum and aluminum alloys can be used for a long time after being supplemented and adjusted.

Each liter of activator can handle 10-20 square meters of workpiece. The activator solution is stable and easy to maintain. The activator usually only needs to replenish the concentrate and adjust the pH with ammonia. The consumption of activator is 100d?/100-150ml. Since the workpiece is brought out, if the liquid level drops, the activator can be added to the specified volume in the reduced volume.

3 Conclusion

The new technology of direct electroless nickel plating of aluminum alloys and the use of new direct electroless nickel plating technology have a simple operation procedure, are easy to use, and have no technological problems. The rate of finished products is as high as 98%, which completely solves the problem of the chemical plating yield of gravity-cast aluminum wheel blanks. defect. The process protects the environment and benefits the country and the people. Save time, effort, greatly improve the production efficiency, save a lot of money, reduce the operating costs of the enterprise, and bring invaluable comprehensive economic benefits to the company.