Gradient coating for boiler tail heating surface and preparation method thereof

Abstract

The invention discloses a gradient coating for a boiler tail heating surface. The gradient coating comprises a first coating, a second coating and a third coating, wherein raw materials of each coating comprise niobium carbide powder, modified graphene powder and zirconium-nickel-based amorphous alloy powder. The gradient coating has the advantages that along with the increase of the distance between the gradient coating and the boiler tail heating surface used as a base body, the contents of the modified graphene, the niobium carbide and the zirconium-nickel-based amorphous alloy in the single coating are respectively in gradient change, so that the smoke gas corrosion resistance and the soot erosion abrasion resistance of the whole coating can be optimally matched, the effect of the gradient coating on protecting the boiler tail heating surface is fully realized, the stress concentration caused by too great difference between the thermal expansion coefficients of the coating and thebase body is effectively reduced, the bonding strength of the coating and the base body of the boiler tail heating surface is effectively improved, and the cracking and peeling risk of the coating isreduced.

Description

technical field [0001] The invention belongs to the technical field of thermal spraying treatment, and in particular relates to a gradient coating for a heating surface at the tail of a boiler and a preparation method thereof. Background technique [0002] The flue gas discharge temperature of industrial coal-fired boilers is high, which has a serious impact on the environment and will also lead to waste of valuable flue gas waste heat resources. Installing a flue gas waste heat recovery device at the tail flue of the boiler can save energy and avoid flue gas waste heat resources waste, but it needs to add more low-temperature heating surface area, and at the same time, a large amount of acid gas will be generated during fuel combustion. When the temperature of the low-temperature heating surface of the energy-saving device installed at the tail flue of the boiler is lower than the acid dew point temperature, A large amount of acid will condense on the heated surface, causin...

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Problems solved by technology

[0005] Amorphous materials have unique and excellent properties compared with traditional crystalline materials. Amorphous alloys do not have crystal defects such as grain boundaries and dislocations, and have better corrosion resistance Wear resistance, and there will be no work hardening of traditional alloys during deformation, so it is a new type of material with great development prospects, but in practice, it is difficult for amorphous materials to be widely promoted and applied as large structural materials

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