Wear-resisting and corrosion-resisting coating for boiler pipe wall and preparation method thereof

A corrosion-resistant coating, boiler tube technology, applied in the direction of coating, metal material coating process, melt spraying, etc., to prevent grain growth, simplify the process flow, and refine the coating structure.

Active Publication Date: 2018-09-11
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the thermal spray coatings applied to the "four tubes" are mainly nickel-chromium alloy coatings and composite ceramic coatings (Cr 3 C 2 -NiCr), Cr 3 C 2 -NiCr coating has excellent high temperature corrosion resistance, but with the improvement of technical requirements and the continuous expansion of application fields, conventional Cr 3 C 2 -NiCr coating can no longer meet the demand

Method used

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  • Wear-resisting and corrosion-resisting coating for boiler pipe wall and preparation method thereof
  • Wear-resisting and corrosion-resisting coating for boiler pipe wall and preparation method thereof
  • Wear-resisting and corrosion-resisting coating for boiler pipe wall and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] The powder used for spraying contains nano-CeO 2 Powder weight percentage is 0%; Cr 3 C 2 -NiCr powder weight percent is 100%.

[0034]The substrate used for spraying is T91 special steel, and the surface of the substrate is degreased, derusted and sandblasted before spraying. Preheat the substrate to 120°C, preheat the powder to 100°C, and then spray with active combustion high-velocity gas spray (AC-HVAF). The main spraying process parameters are: spraying distance 320mm, gas chamber 1 pressure 97psi, gas chamber 2 Pressure is 102psi, air pressure is 108psi, N 2 The air flow rate is 70L / min, the powder feeding rate is 72g / min, the spraying angle is 90°, and the number of spraying times is 6 times; the thickness of the sprayed coating is 200μm.

Embodiment 2

[0036] Use mechanical mixing powder, the powder includes CeO with a particle size of 10-35nm 2 Powder and Cr with a particle size of 15-45 μm 3 C 2 -NiCr powder two components. Nano CeO in powder 2 Powder weight percentage is 10%; Cr 3 C 2 -NiCr powder weight percent is the balance. During preparation, put the two powders into a ball mill, set the speed at 200r / min, and mix for 8 hours, and use them after uniform mixing. After mixing, the particle size of the obtained mixed powder is between 25 and 35 μm, and the shape is spherical, CeO 2 Particles attached to Cr 3 C 2 -NiCr particle surface.

[0037] The substrate used for spraying is T91 special steel, and the surface of the substrate is degreased, derusted and sandblasted before spraying. Preheat the substrate to 110°C, preheat the powder to 110°C, and then use active combustion high-velocity gas spraying (AC-HVAF) for spraying. The main spraying process parameters are: fuel type is propane, fuel I pressure is 97P...

Embodiment 3

[0039] Use mechanical mixing powder, the powder includes CeO with a particle size of 10-35nm 2 Powder and Cr with a particle size of 15-45 μm 3 C 2 -NiCr powder two components. CeO in powder 2 Powder weight percentage is 20%; Cr 3 C 2 -NiCr powder weight percent is the balance. During preparation, put the two powders into a ball mill, set the speed at 200r / min, and mix for 8 hours, and use them after uniform mixing. After mixing, the particle size of the obtained mixed powder is between 25 and 35 μm, and the shape is spherical, CeO 2 Particles attached to Cr 3 C 2 -NiCr particle surface.

[0040] The substrate used for spraying is T91 special steel, and the surface of the substrate is degreased, derusted and sandblasted before spraying. Preheat the substrate to 100°C, preheat the powder to 130°C, and then use active combustion high-velocity gas spraying (AC-HVAF) for spraying. The main spraying process parameters are: fuel type is propane, fuel I pressure is 100Psi, ...

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Abstract

The invention discloses a wear-resisting and corrosion-resisting coating for a boiler pipe wall and a preparation method thereof and belongs to the technical field of surface engineering. According tothe method disclosed by the invention, a compound coating is formed by spraying powder on a base material (T91) through an active combustion high-velocity gas spraying technology (AC-HVAF); the powder is prepared from two components including Cr3C2-NiCr ceramic powder and CeO2 powder; the doping percent of the CeO2 powder is 0 to 20 weight percent and the balance is the Cr3C2-NiCr ceramic powder.The rare-earth element doped ceramic coating prepared by the method has dense tissues and the tissues are uniformly distributed; the coating has a flat structure and is tightly combined with the boundary of a matrix. Furthermore, the coating doped with the CeO2 powder, which is prepared by the method, has more dense tissues and the tissues are dispersed and distributed in the coating; the coatinghas higher corrosion resistance and high-temperature oxidization resistance, so that the anti-washout and abrasion-resisting performance and the high-temperature oxidization resistance of a boiler pipeline in an application process are easy to improve.

Description

technical field [0001] The invention relates to the technical field of preparation of metal-based ceramic composite materials, in particular to a wear-resistant and corrosion-resistant coating for boiler tube walls and a preparation method thereof. Background technique [0002] So far, my country's power industry is mainly based on thermal power generation, and in the process of power generation, coal is used as fuel for power generation accounting for about 50% of my country's total coal consumption. form SO 2 , CO 2 , nitrogen oxides and other acid gases. With the continuous development of the thermal power industry, the demand for high-load and large-capacity boiler equipment is increasing, and the high-temperature corrosion Performance requirements such as wear and tear are also getting higher and higher. Therefore, it is very important to find a high-temperature corrosion-resistant coating. [0003] High temperature corrosion is a very serious problem in boilers, ga...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C4/129C23C4/06C22C27/06C22C32/00
CPCC22C27/06C22C32/0005C23C4/06C23C4/129
Inventor 曾德长罗政郑志刚余红雅王刚邱兆国
Owner SOUTH CHINA UNIV OF TECH
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