Sealing treatment of thermal spraying tungsten carbide coating

       Thermal spraying tungsten carbide technology is a surface treatment technology that can greatly increase the hardness of metal products



The entire construction process of thermal spraying tungsten carbide coating is divided into four items: surface pretreatment of workpiece → preheating of workpiece → spraying → post-treatment of coating. Sealing treatment is the last coating post-treatment process of thermal spraying tungsten carbide. In order to better and effectively achieve the protection of the sprayed layer and prolong the service life of its base structure, it is necessary to carry out a sealing treatment.

In general, the porosity range of tungsten carbide coating is quite large. An oxygen flame spray is sometimes as high as 15%, and the high velocity oxygen spray (HVOF spray) layer is less than 1%. When exposed to air, steam, paint industry, chemically active materials, corrosive atmosphere and high temperature environment, corrosion holes introduce elements, chemical or electrochemical corrosion of coatings and substrates, resulting in the failure of tungsten carbide coatings.

Therefore, in order to have a longer protection period, thermal spraying companies need to use sealing treatment. The so-called sealing treatment is to use liquid organic materials without dyes or blending paints, also called ton ratio agents, and brush on the surface of the tungsten carbide coating to carbonize The pores of the tungsten coating are closed.