A Brief Summary of Spring Surface Treatment
The corrosion of springs can be divided into chemical corrosion and electrochemical corrosion according to the type of reaction. They are all the result of changes in metal atoms or electron gains and losses on the surface of the spring. Spring anti-corrosion methods generally use a protective layer, which can be divided into: metal protective layer, chemical protective layer, non-metal protective layer, and temporary protective layer according to the nature of the protective layer. The first three methods are emphasized here.
Stainless steel springs and copper wire springs have a certain anti-corrosion ability, so they are generally not treated with anti-corrosion.
1.Metal protective layer of spring
There are many types of metal protective layers. In the case of springs, electroplated gold is generally used to obtain metal protective layers. The plating protection layer can not only protect from corrosion, but also improve the appearance of the spring. Some electroplated metals can also improve the working performance of springs, such as increasing surface hardness, increasing anti-wear, improving thermal stability, and preventing radiation corrosion. However, if it is purely for the corrosion of the spring, electroplated zinc layer and electroplated cadmium layer should be generally used.
2.Chemical protection layer of spring
A chemical reaction method is used to form a dense protective film on the surface of the spring to prevent the spring from corrosion. Oxidation treatment and phosphating treatment are usually used. Oxidation treatment and phosphating treatment have low cost and high production efficiency. Generally, spring manufacturers use oxidation treatment as anticorrosive treatment.
3.Non-metal protective layer of spring
The non-metallic protective layer is a dip or spray coating of an organic substance on the surface of the spring, such as paint, asphalt, plastic, etc. to protect the spring from corrosion.
The non-metallic protective layer has a thicker film layer, good chemical stability, and better mechanical anti-corrosion effect, but has lower hardness and is easy to be scratched and damaged, and at the same time the film layer has aging phenomenon.