Preparation method of high-temperature resistant and anti-abrasion-and-corrosion gradient coating used for circulating fluidized bed boiler

Abstract

The invention discloses a preparation method of a high-temperature resistant and anti-abrasion-and-corrosion gradient coating used for a circulating fluidized bed boiler. The preparation method includes the steps that firstly, sand blasting roughening is performed on the surface of a circulating fluidized bed boiler part; secondly, the surface subjected to sand blasting roughening is washed with acetone and ethyl alcohol successively and is dried; thirdly, a NiCrBSi intermediate coating is sprayed on the roughened and cleaned surface in a plasma spraying manner, then Cr3C2-NiCr-BN-Si3N4 particles are sprayed in a plasma spraying manner, and the conditions of a plasma spraying process includes that the main gas pressure is 0.7-1.0 MPa, the auxiliary gas pressure is 0.6-0.9 MPa, the main air flow is 1300-1800 l/h, the auxiliary air flow is 900-1100 l/h, the arc current is 450-600 A, the arc voltage is 85-100 V, the powder feeding gas pressure is 0.2-0.4 MPa, the powder feeding gas flow is 280-400 l/h, the spraying distance is 100-150 mm, the spraying speed is 2-3 kg/h, and the coating thickness is 1-2.5 mm. The coating can be resistant to high temperature corrosion and high temperature abrasion and corrosion when used for the circulating fluidized bed boiler, and the coating is firm and cannot fall.

Description

technical field [0001] The invention relates to the technical field of materials, in particular to a circulating fluidized bed boiler high temperature resistant and anti-abrasion Cr 3 C 2 -The preparation method of NiCr-BN gradient coating. Background technique [0002] The difference between a circulating fluidized bed boiler and a conventional boiler is that its combustion system is different. Gas-solid material separation equipment and solid material recirculation equipment are the main features of circulating fluidized bed boilers. The combustion of circulating fluidized bed boiler includes two processes of internal circulation and external circulation. The internal circulation is the circulation process in the furnace, that is, the flue gas moving at high speed in the furnace is in close contact with the solid particles with strong turbulent disturbance, and there are a large number of Fluidized combustion reaction process with particle backmixing. The outer circulat...

AI Technical Summary

Problems solved by technology

This defect has not been well resolved, which limits the further popularization and application of circulating fluidized bed boilers.