In addition to increase the surface appearance of plating givers, but also because of the surface coating on the metal substrate coating, and change the surface properties and size, so that it can reach the material itself can not do things such as giving goods rust, wear prevention function, or improve the conductivity, lubricity, heat resistance, weather resistance and strength etc..
Therefore, the plating as an application of a wide range of surface treatment process, but not every substrate and coating can be matched with each other, the choice of substrate and coating is also a skill. Each kind of coating has a unique nature and use, in the choice of coating in addition to consider the application properties of the coating, but also should consider the processing technology and cost issues.
Some requirements for the selection of coating:
1, part of the working environment and requirements
The electroplating requirements most parts of the have good protection, environmental factors is essential for the corrosion of metal materials, such as atmospheric environment (industrial atmosphere, ocean atmospheric), working temperature, humidity, dielectric properties, mechanical conditions, so the environmental factor is the choice of coating the first consideration. At the same time, we should also consider the electrical properties, magnetic properties and other specific functions.
2, the type and nature of parts
Have a great influence on species and physical and chemical properties of matrix material type and structure on the choice of the coating, such as protective coating of iron and steel materials in general in the atmosphere should be made of galvanized layer, anode coating, simple structure. Because of the copper, nickel and chromium are relative to the iron and steel cathodic coating, coating requirements should have smaller porosity and proper thickness, but also should be based on the pretreatment process of selection and corresponding materials, can obtain good combination of coating and the collective.
3, parts of the structure, shape and size tolerance
The complex structure or with deep hole parts, should be used for covering capacity and good dispersion capacity of bath, or on the surface of the deep depression or not plated coating, or inhomogeneous coating. In general, it is very difficult to solve the problem that the inner wall of the thin tubular part is hard to get a complete coating. For precision parts with small size tolerances and strict requirements, a thin layer of good performance must be used.
4, the nature and life of the coating
The coating can change the surface properties of the substrate material, and can prolong the service life of the parts, but is not permanent. In particular, protective coating, after a certain period of time still need to be repaired or replaced. The properties and the life of the coating should be adapted to the specific requirements of the parts to meet the expected purpose.
The properties of different coatings are different from each other. Therefore, the proper plating should be chosen according to different working conditions and environment, and the cost of electroplating processing.