Thermal spray and Cold Spray

There are two main technologies in the field of spraying: "thermal spraying" and "cold spraying". But few people understand the technical differences between them. You can see the brief introduction below:

Thermal spraying is a surface treatment by which a solid material is heated to a molten or semi-molten status and sprayed onto a substrate with a high speed to form a film, which has the property that we desired to achieve the purpose of surface treatment technology of modified substrate. Since the thermal spray coating has a special layer structure and a number of small holes, the combination of the coating and the substrate is generally mechanical, and the bonding strength is lower. In many cases, thermal spraying can cause phase change, decomposition, volatilization and oxidation of some compositions.

Cold spraying is called relative to the thermal spraying. During the cold spraying process, the spraying particle impact on the substrate surface with a high speed (500~1000m/s). The particles don’t melt during the whole process and maintain the solid status, which undergo plastic deformation to form the coating layer. Cold spraying technology has developed rapidly in Russia, America and Germany in recent years.

Thermal spray forms the coating by high temperature and the cold spray forms the coating by high speed. The two techniques have their own advantages and don’t conflict each other.