Enamel stirred reaction vessels are commonly used production equipment in the petrochemical, pharmaceutical and other industries, and their working conditions are often very harsh. Often exposed to fluctuations in pressure, changes in temperature, corrosion by media, and so on. During the production process of the reaction vessel, various faults often occur, among which the most common one is the peeling of the enamel.

Enamel is a composite material with properties such as impact resistance, corrosion resistance, smoothness and beauty, insulation, heat resistance and wear resistance, which is formed by coating one or more layers of opaque or transparent non-metallic materials on the surface of metal through a special process. These two are firmly bonded together through physical and chemical reactions at high temperatures. It has the strength of metal and the chemical stability of glass. It has excellent corrosion resistance to organic acids, inorganic acids and organic solvents except hydrofluoric acid and concentrated sulfuric acid. Enamel reaction vessels are indispensable anti-corrosion equipment in the chemical industry.

At present, there are many repair methods for enamel kettles in our country, but the repair life is generally not long. So far, no mature experience has been found to make metal or non-metal repair reach the original enamel performance. Only by improving the quality of enamel repair can the service life of equipment be prolonged. The most commonly used methods are as follows:

(1) Re-firing: It requires disassembling the equipment, which takes a long time and incurs high costs, causing serious waste for enterprises

(2) Corrosion-resistant metal repair: The repair effect is poor, and enterprises generally do not adopt it

(3) Mixed repair of corrosion-resistant metal and paint: It is prone to corrosion at the bonding point between the repaired metal and the paint, leading to failure

(4) Non-metallic repair: Two issues need to be addressed: ① Enhancing self-bonding strength ② reducing temperature difference stress