How to achieve effective zinc plating on cast iron parts? First, understand why cast iron parts are difficult to plate. Then, identify the necessary measures to take during the plating process (such as using the correct potassium chloride zinc plating brightener). Only then can a satisfactory plating layer be achieved.
The reasons for the difficulties in electroplating cast iron parts
Because the graphite in cast iron can reduce the overpotential for hydrogen release and hinder the deposition of metal. Moreover, the rough and uneven surface of the casting, along with its porous nature, also lowers the hydrogen release potential, making hydrogen more prone to escape.
As a developer of electroplating additives, Bigely has also discovered that when castings are corroded in acid, if the corrosion is excessive, the hydrogen evolution reaction becomes more severe, which can easily reduce the cathode current efficiency. As a result, it is difficult to deposit a coating on the cast iron parts. Therefore, appropriate measures should be taken during the corrosion, electroplating and post-treatment processes.
Etching
After sandblasting the cast iron parts to remove rust and oxide scale, no further strong corrosion is required. A weak corrosion (with a short duration) is sufficient to achieve a clean surface effect. The product, Bigely acid salt activator BC-629, can be used. This product has a mild and neutral formula and will not damage the substrate.
Galvanizing
After adding the Bigely potassium chloride zinc plating brightener to the plating solution, the current efficiency can be improved (above 95%), and a larger current density can be adopted. For example, when starting the plating process, it is recommended that the electroplating factory customers use a large current for impact plating (higher than the normal current by twice). This can achieve a more ideal coating quality.
About us
Guangdong Bigely Technology Co., Ltd. ,founded in 2003, is a high-tech enterprise integrating R & D，production, sales and service, specializing in the production of electroplating chemicals. As a fast growing electroplating chemicals supplier in China, Bigely has over 20 years' experience in electroplating additives production and own production base of 5000 square meters. We can produce 15,000 tons of electroplating additives every year, which can fully meet the needs of customers.
If you need our high-quality electroplating additives, please contact us. We can provide you samples for test, and also provide a series of services.
