Acid corrosion-resistant enamel coating on weather-resistant structural steel surface and preparation method thereof

Abstract

The invention discloses an acid-corrosion-resistant enamel coating on the surface of weather-resistant structural steel and a preparation method thereof. The preparation method of the acid-corrosion-resistant enamel coating on the surface of weather-resistant structural steel of the present invention comprises: a) melting enamel glaze, b) preparing enamel glaze powder, c) alkaline degreasing treatment of weather-resistant structural steel, d) enamel coating Spraying and firing at high temperature, wherein, the enamel glaze material has two kinds, which are enamel enamel A and enamel enamel B respectively. The acid-corrosion-resistant enamel coating on the surface of the weather-resistant structural steel obtained by the preparation method of the invention has the advantages of excellent acid-corrosion resistance, especially sulfuric acid resistance, high bonding strength, and long service life. In addition, the preparation method of the present invention is simple, adopts two kinds of glazes to be melted separately, and the surface of the weather-resistant structural steel is treated with alkaline degreasing, which improves production efficiency, saves energy consumption, reduces the production cost of enamel coating, and is suitable for large-scale popularization and application. .

Description

technical field [0001] The invention belongs to the field of inorganic protective coatings, in particular to an acid-corrosion-resistant enamel coating on the surface of weather-resistant structural steel and a preparation method thereof. Background technique [0002] Weather-resistant structural steel is to add a small amount of alloying elements, such as Cu, P, Cr, Ni and rare earth elements, to the steel to form a protective layer on the surface of the metal substrate, thereby improving the weather resistance of the steel plate. However, when weathering structural steel is used in a corrosive environment, such as heat exchange elements in desulfurization and denitrification heat exchangers, due to the poor sulfuric acid corrosion resistance of weathering structural steel, especially in desulfurization and denitrification heat exchangers, when the local temperature reaches At the dew point of sulfuric acid, the weather-resistant structural steel is easily corroded, resulti...

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Problems solved by technology

However, due to the excessive low melting point components (such as zinc oxide, sodium oxide, etc.) contained in ordinary enamel coatings as co-solvents, the low melting point components are easy to react with Cr in the alloy matrix during high temperature service. , and finally further oxidized on the surface of the coating to generate a large amount of chromate spinel corrosion products, such as ZnCr2O4, which greatly reduces the oxidation resistance of the enamel coating, and the addition of a large number of low melting point components breaks the silicon-oxygen tetrahedron The silicon-oxygen bond in the enamel makes it easier for the alloy ions in the corrosive medium to penetrate into the enamel coating, thereby further reducing the softening point of the enamel coating, making it easier for sulfur and chloride ions to penetrate through the enamel coating to the alloy matrix, seriously Affects the corrosion resistance of enamel coatings