Generally speaking, coating is a material that can be coated on the surface of the object to be coated and can form a firmly attached continuous film. It can be inorganic, such as electroplating copper, electroplating nickel, electroplating zinc, etc. It can also be organic, such as most organic polymer materials, which constitute the main part of the coating market today.

The color, luster, pattern and flatness of the paint. When objects of different materials are painted, they can get colorful appearance, play a role in beautifying the human living environment, and make an important contribution to human material life and spiritual life.