Introduction of Four Kinds of Common Electroplating

Introduction of Four Kinds of Common Electroplating

Electroplating refers to a surface treatment process in which the cations to be plated are deposited on the metal surface of the base metal by electrolysis in a salt solution containing the metal to be plated, using the metal to be plated as the cathode.

1. zinc plating

Galvanizing is mainly used for corrosion protection of ferrous metals such as iron and steel. The appearance of the galvanized layer is blue-white, soluble in acid and alkali. Zinc is amphoteric and hardly changes in dry air. It can react with oxygen and carbon dioxide to form basic zinc carbonate in moist air, which has a certain protective effect. Zinc sulfide reacts with sulfur compounds to form zinc sulfide, which is easily eroded by chloride ions, so it is unstable in seawater. After passivation treatment, the protective and decorative properties of zinc coating are improved significantly.

2. copper plating

Copper coating is pink, uniform and meticulous. The tone of copper coating plated by different processes is different. Copper coating is widely used, mainly used as bottom coating, intermediate coating, and surface coating. In addition, copper plating can also be used for anti-carburization of steel parts, printed circuit boards, plastic plating and electroforming, etc.

3. nickel plating

Nickel plating can be used as a surface coating or as a bottom or middle layer of multilayer electroplating. Nickel coating is widely used. It is a cathodic protective coating for steel matrix. Therefore, its protection ability is related to the porosity of the coating. In order to improve the protection of nickel, multi-layer nickel plating can be used, such as semi-bright nickel/bright nickel/chromium, semi-bright nickel/high sulfur nickel/bright nickel/chromium, semi-bright nickel/high sulfur nickel/bright nickel/nickel sealing/micro-porous chromium, semi-bright nickel/bright nickel/high stress nickel/micro-cracked chromium, etc. Nickel coating as the bottom layer of decorative gold, palladium-nickel and silver plating is widely used in hardware decoration and other industries.

4. chromium plating

Chromium is a silver-white metal with a slight blue hue. Chromium coating has good chemical stability, good reflectivity, and can maintain gloss and color for a long time in general atmospheric environment. Chromium surface is hydrophobic, oil-repellent, not easily polluted, and the coating is hard and not easily scratched. Therefore, it can be used for decorative, wear-resistant and corrosion-resistant protective decorative coatings and functional wear-resistant coatings. Chromium plating solution can be divided into two categories: hexavalent chromium plating solution and trivalent chromium plating solution. The former is traditional chromium plating, which has been used for nearly a hundred years, but due to the harm of hexavalent chromium to human body and environment. At present, trivalent chromium plating has many shortcomings. The color of trivalent chromium plating has not reached the hexavalent chromium tone. At present, it is more like the color of stainless steel.