Introduction of thermal spraying sealant

Thermal spraying is a surface treatment method with high speed impact on the surface of the substrate by melting or semi melting particles, forming a surface coating with certain characteristic. This coating is made up of particles superimposed on each other. The holes are inevitable between the superimposed particles, especially the existence of perfoliate holes. The corrosion medium can reach the surface of the protected substrate by perforation, making the coating and the matrix having chemical or electrochemical corrosion. The corrosion product is accumulated on the surface, and the thermal spraying layer will crack and peel off, which eventually leads to the failure of the coating.

The main way to solve the hole problem in thermal spraying coating is to use the sealing technique, which is to deposit and infiltrate the sealant into the thermal spraying coating to fill the gap of the thermal spraying coating, thus realizing the sealing treatment of the thermal spraying coating.

What are the performance requirements for the sealant?

There are many kinds of sealants. In order to achieve good sealing, the sealant must meet the following requirements:

1. There must be enough curved pores to permeate, high permeability and full filling.

2. Chemical coating material itself is chemical solvent corrosive medium, and sealant that can not withstand the erosion of the medium and sealing is not acceptable. 

3. The sealant should withstand certain mechanical external functions, meaning not being peeled off or broken because of mechanical damage.

4. Sealant under stable working environment shouldn’t occur evaporation or melting decomposition and other physical changes.

5. Do not react to coating or special coating and process.

6. The working environment and chemical stability of sealant do not reduce the coating and matrix properties.

7. When the coating is used for food industry, it should be non-poisonous.

8. Ensure safe construction.