Types of Plating and Their Uses – What Materials Are Used in Metal Plating

According to the purposes, metal plating can be divided into the following processes. 

1. Metal Plating for Protective Purposes

The main function is to protect the base metal from corrosion, and there is no requirement for product decoration. It is represented by zinc plating, cadmium plating, and other coatings.

1) Zinc plating: an anodic coating on steel parts under atmospheric conditions. After various passivations (color, black, yellow, military green, blue, and white), the protection performance of the coating and the appearance are improved significantly. It is mainly used to prevent the corrosion of iron and steel parts. Its coating has a low price, excellent corrosion resistance, and wide application.

2) Cadmium plating: an anodic coating for steel parts in the ocean and high-temperature atmosphere. The coating is relatively stable, with strong corrosion resistance and good lubrication performance. It is widely used in the aviation and electronic industries.

2. Metal Plating for Decorative Purposes

In addition to protecting the base metal, it also makes the parts beautiful, such as nickel plating, chromium plating, copper plating, etc.

1) Nickel plating: a cathodic coating for steel parts. It has higher hardness, higher corrosion resistance than copper, and is resistant to alkalis and acids. Commonly used for copper/nickel/chromium plating of iron and steel parts – an intermediate layer of decorative coating and pre-plating before acid copper plating.

2) Chromium plating: cathodic coating for steel parts. It has high heat resistance, good hardness at room temperature, good wear resistance, and strong light reflection, and is widely used to improve the hardness, wear resistance, light reflection, repair size, and decoration of parts.

3) Copper plating: a cathodic coating for zinc, iron, and other metals. It is often used as the bottom or middle layer of copper/nickel protective decorative coating on various metal substrates or some plastics, and can also be used in printing circuits, electroforming molds, and other aspects.

3. Metal Plating for Functional Purposes

It has a certain protective effect and is mainly used for special work purposes, such as meeting the requirements of hardness, wear resistance, conductivity, electromagnetic property, heat resistance, etc. 

1) Tin plating: a cathodic coating for steel parts. Therefore, only when the coating has no pores can the steel parts be mechanically protected from corrosion. It has high chemical stability, has little effect on sulfur and sulfide, and has good welding performance and shielding effect on nitriding.

2) Silver plating: the silver plating layer is a cathodic coating for common metals, which has excellent conductivity, soldering performance, and stable chemical properties. It is mainly used for conductive parts and welding parts in the electrical industry, as well as protective decorative coatings, such as musical instruments, tableware, optical instruments, and handicrafts.

3) Chromium (chrome) plating: a cathodic coating for steel parts. It has high heat resistance, good hardness at room temperature, good wear resistance, and strong light reflection, and is widely used to improve the hardness, wear resistance, light reflection, repair size, and decoration of parts.