High-temperature-resistant anti-corrosion anti-coking coating with composite structure and spraying method

Abstract

The invention relates to a high-temperature-resistant anti-corrosion anti-coking coating with a composite structure and a spraying method. The high-temperature-resistant anti-corrosion anti-coking coating comprises a metal coating coated on the surface of a metal pipe wall and a ceramic coating sprayed on the surface of the metal coating, the metal coating is formed by thermally spraying metal composite powder, and the metal composite powder comprises alloy powder and zirconium oxide micro powder in a weight ratio of (10-20): 1; the ceramic coating is formed by cold spraying ceramic composite powder on the surface of the metal coating, and the ceramic composite powder comprises the following components by weight, 30-50 parts of silicon carbide micro powder, 10-25 parts of aluminum oxide micro powder, 15-35 parts of zirconium oxide micro powder and 10-20 parts of zirconium boride micro powder. The zirconium oxide micro powder in the metal coating is embedded in the metal coating in a molecular embedding mode to achieve the effect of adjusting the thermal expansion coefficient, an outer layer and a metal pipe wall are tightly connected, the binding force of the coating and the pipe wall can be improved, and a certain anti-corrosion effect can be achieved. The ceramic coating is sprayed at normal temperature and then used at high temperature to form a ceramic membrane, so that the effects of corrosion prevention and coking prevention are achieved.

Description

technical field [0001] The invention relates to the technical field of metal coatings, in particular to a high-temperature-resistant, anti-corrosion, and anti-coking coating of a composite structure and a spraying method. Background technique [0002] During the coal-fired combustion process of coal-fired boilers, the heating surface of the water wall pipes is coked, and the superheater and reheater pipes accumulate dust, which reduces the heat transfer efficiency of the boiler, increases the exhaust gas temperature, and increases energy consumption. Coking seriously produces sulfate corrosion and shortens the service life of the boiler. These problems will seriously affect the boiler safety and economical operation. The existing metal coatings only have the effect of anti-wear and anti-corrosion to a certain extent, and do not have the ability to solve the problems of high-temperature corrosion, anti-coking and heat transfer performance of the inner wall of high-temperatur...

AI Technical Summary

Problems solved by technology

[0002] During the coal-fired combustion process of coal-fired boilers, the heating surface of the water wall pipes is coked, and the superheater and reheater pipes accumulate dust, which reduces the heat transfer efficiency of the boiler, increases the exhaust gas temperature, and increases energy consumption. Severe coking produces sulfate corrosion, shortening the service life of the boiler, etc.

The above problems will seriously affect the safety and economical operation of boilers.

The existing metal coatings only have the effect of anti-wear and anti-corrosion to a certain extent, and do not have the ability to solve the problems of high-temperature corrosion, anti-coking and heat transfer performance of the inner wall of high-temperature boilers; ceramic coatings have better anti-corrosion and anti-coking effects , but due to the thermal expansion coefficient mismatch with the metal tube wall in the boiler, the bonding force is not enough, and the wear resistance is not as good as the metal coating. To improve the comprehensive service life and performance of the coating, it is necessary to find an ideal method

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