New Technology for Direct Electroless Nickel Plating on Automotive Aluminum Wheels (1)

[China Aluminum Network] With the rapid development of China's auto industry, automotive aluminum wheel plating technology is rapidly rising in China. The new process of direct electroless nickel plating on aluminum wheels is a new technology developed on the basis of A356 die-cast aluminum alloy. It breaks the limitation that the aluminum wheel plating can only be electroplated by the second zinc plating treatment, so that the electroplating of nickel can be carried out directly without using the secondary zinc plating for the aluminum wheel plating. It overcomes the tendency of the electrolyte to be affected by harmful impurities in the secondary zinc dipping solution, contaminating the electroless nickel plating solution, making the quality of the plating layer unreliable, the operation procedure of the electroless nickel plating being complicated, and the technical difficulty being great. The electroless nickel plating solution is frequently adjusted and replaced. All the deficiencies. The activated aluminum wheels, like the steel parts, deposit a layer of bright, dense and well-bonded electroless nickel plating on the surface. Therefore, this process is particularly suitable for automotive aluminum hub plating production lines.

First, test data:

1, binding force

The test piece was A356 die-cast aluminum alloy. After electroless nickel plating, the workpiece was warmed to 200-300 degrees 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 plated layer. The boring knife method, saw blade method and tape method test are all superior to the secondary zinc leaching process.

2. Corrosion resistance

The coating is resistant to salt spray for more than 66 hours. (CASS inspection)

Second, the bath stability, environmental awareness ratio:

1, sink zinc agent

Pre-plated nickel baths cause pre-plated nickel baths to be contaminated due to the introduction of zinc sinks. In order to maintain the stability of nickel baths, frequent adjustments and constant bath changes are required. It wastes a lot of manpower and material resources and adds unnecessary expenses. Moreover, because of the heavy metal ions and poisonous cyanide ions contained in the sink zinc agent, it has been strictly restricted by the environmental protection department. The use of cyanogen zinc sinks pollutes the environment, causing harm to the country and the public.

2, activator

The direct electroless nickel plating activator for aluminum wheels is a non-toxic, odorless, non-pollution, green and environment-friendly new product with special international advanced level in the field of electroplating. Electroless nickel plating is performed directly with an activator, which does not contaminate the bath and the bath is stable. A small amount of activator is brought into the electroless nickel plating bath, which promotes the autocatalytic function of the electrolyte and enhances the bonding force between the aluminum substrate and the plating layer. The operation procedure is simple, easy to use, and technically troublesome. Protect the environment, benefit the country and the people, and benefit the generations.

Third, work efficiency:

1. The use of activators for direct electroless nickel plating requires only 7 processes to complete the electroplating of acid bright copper.

2. The use of zinc sinking agent for secondary zinc immersion treatment requires 23 processes to complete the work of plating the acid bright copper.

3, the use of activator for plating can increase work efficiency by more than one third.

Fourth, the ratio of activator and zinc sinker price:

According to an annual output of 150,000 aluminum wheel plating production lines, the surface area of ​​each aluminum wheel hub is 1 square meter, totaling 150,000 square meters.

1, activator treatment

Each liter of activator can handle an area of ​​20-25 square meters, about 7500 liters of activator a year. The price of activator per liter is 40.00 yuan, and the total annual amount is about 300,000 yuan.

2, Shen zinc treatment

Zinc removal agent per liter can handle about 3 square meters without supplementation.

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