CN-122006990-A - Hole sealing method based on porosity of thermal spraying coating

Abstract

The invention belongs to the technical field of hole sealing of thermal spraying coating, and discloses a hole sealing method based on porosity of the thermal spraying coating, wherein a coating is formed on the surface of a substrate through a thermal spraying process, hole sealing glue is applied to the surface of the substrate, the hole sealing glue naturally permeates into the coating under the action of gravity by utilizing the structural characteristic that open pores are mutually communicated, and the surface tension, viscosity and curing conditions of the hole sealing glue are controlled to permeate at least 500 mu m into the coating before curing, so that the open pores are continuously filled; and then carrying out low-temperature curing treatment on the coating to ensure that the hole sealing glue forms a stable hole sealing structure in the pores. After the method is adopted, not less than 95% of open pores in the coating can be effectively closed under the condition of no external pressure or vacuum assistance, so that the voltage resistance of the thermal spraying coating is stabilized above 500V, and the resistance value is improved from megaohm level to gigaohm level, thereby obviously improving the electrical property and corrosion resistance of the coating.

Inventors

• Zhang jiujiu
• BU QINGLEI
• Zhou Chenrui
• FENG XIAOYU

Assignees

• 光晋科技(合肥)有限公司

Dates

Publication Date

20260512

Application Date

20260316

Claims (6)

1. 1. The hole sealing method based on the porosity of the thermal spraying coating comprises the following steps: (1) Forming a coating on the surface of a substrate through a thermal spraying process, wherein pores formed by powder semi-melting, gas entrainment or high-speed impact accumulation in the spraying process exist in the coating, and the pores at least comprise open pores communicated with each other; (2) After the coating is formed, hole sealing glue is applied to the surface of the coating, and the hole sealing glue naturally permeates into the coating along a pore channel under the action of gravity by utilizing the structural characteristic that open pores are mutually communicated; (3) The surface tension, viscosity and curing conditions of the hole sealing glue are controlled, so that the hole sealing glue at least permeates 500 mu m inside the coating before curing, and the open pore is continuously filled; (4) And (3) performing low-temperature curing treatment on the coating after the penetration is finished, so that the hole sealing glue forms a stable hole sealing structure in the pores, and the voltage resistance, the resistance and the corrosion resistance of the coating are improved.
2. 2. The method for sealing porosity of thermal spray coating according to claim 1, wherein the sealing glue is resin sealing glue, the surface tension of the sealing glue is lower than the wetting critical value of the pore wall of the thermal spray coating, and the sealing glue has lower viscosity in an uncured state, so that the sealing glue can fully penetrate the open pores under the action of gravity only without external pressure or vacuum assistance.
3. 3. The hole sealing method based on the porosity of the thermal spraying coating according to claim 2, wherein the resistivity of the hole sealing layer formed by curing the hole sealing glue is matched with the electrical property of the thermal spraying coating, so that the insulation property and the voltage resistance stability of the coating are integrally improved after hole sealing.
4. 4. The method for sealing porosity of thermal spraying coating according to claim 3, wherein the sealing glue is mainly permeated along open pores in the coating and is filled to a depth of at least 500 μm from the surface of the coating before curing, so as to avoid the problem of insufficient internal sealing caused by the sealing glue staying only on the surface layer of the coating, and the sealing glue can still effectively seal not less than 95% of open pores in the coating under the condition that the porosity of the thermal spraying coating reaches 20%.
5. 5. The method for sealing porosity of thermal spray coating according to claim 4, wherein the curing process of the sealing glue is completed at a temperature of not higher than 60 ℃ and the overall curing time is controlled within three days, so as to improve production efficiency while ensuring sealing integrity.
6. 6. The method for sealing a hole based on porosity of a thermal spray coating according to claim 5, wherein the thermal spray coating after the sealing treatment has a withstand voltage performance stable at 500V or higher, and an overall resistance value is increased from megaohm to gigaohm before sealing.

Description

Hole sealing method based on porosity of thermal spraying coating Technical Field The invention belongs to the technical field of hole sealing of thermal spraying coatings, and particularly relates to a hole sealing method based on porosity of a thermal spraying coating. Background The thermal spraying technology is a surface modification technology for forming a coating by heating a spraying material to a molten or semi-molten state by a high-energy heat source and depositing the spraying material on the surface of a substrate in a high-speed spraying mode, and is widely applied to the fields of wear resistance, corrosion resistance, electric insulation and the like. However, due to factors such as semi-molten state of the spray powder, gas entrainment during the spraying process, irregular accumulation of molten particles after high-speed impact, rapid cooling, etc., a certain number of pores are usually formed inside the thermal spray coating, and such pores belong to structural defects which are unavoidable in the spraying process. Depending on whether the pores are connected, the coating pores may be divided into open pores and closed pores, wherein the open pores are connected to each other, and a flow channel of air and water vapor is easily formed, thereby causing corrosion of the substrate and reducing electrical insulation properties of the coating. In order to solve the problems, the prior art generally introduces a hole sealing process after the coating is formed, but the prior hole sealing process generally has the problems of insufficient fluidity, limited penetration depth, long curing time and the like of hole sealing glue, so that the hole sealing in the coating, especially in the area close to a substrate, is insufficient, and finally, the use requirements of high withstand voltage and high insulating performance are difficult to stably meet. Disclosure of Invention The invention aims to provide a hole sealing method based on porosity of a thermal spraying coating, so as to solve the problems in the background art. In order to achieve the above purpose, the invention provides a hole sealing method based on thermal spraying coating porosity, comprising the following steps: (1) Forming a coating on the surface of a substrate through a thermal spraying process, wherein pores formed by powder semi-melting, gas entrainment or high-speed impact accumulation in the spraying process exist in the coating, and the pores at least comprise open pores communicated with each other; (2) After the coating is formed, hole sealing glue is applied to the surface of the coating, and the hole sealing glue naturally permeates into the coating along a pore channel under the action of gravity by utilizing the structural characteristic that open pores are mutually communicated; (3) The surface tension, viscosity and curing conditions of the hole sealing glue are controlled, so that the hole sealing glue at least permeates 500 mu m inside the coating before curing, and the open pore is continuously filled; (4) And (3) performing low-temperature curing treatment on the coating after the penetration is finished, so that the hole sealing glue forms a stable hole sealing structure in the pores, and the voltage resistance, the resistance and the corrosion resistance of the coating are improved. Preferably, the hole sealing glue is resin hole sealing glue, the surface tension of the hole sealing glue is lower than the wetting critical value of the pore wall of the thermal spraying coating, and the hole sealing glue has lower viscosity in an uncured state, so that the hole sealing glue can fully penetrate the open pore under the action of gravity only under the condition that external pressure or vacuum assistance is not applied Preferably, the resistivity of the hole sealing layer formed after the hole sealing glue is cured is matched with the electrical property of the thermal spraying coating, so that the insulation property and the voltage resistance stability of the coating are integrally improved after hole sealing. Preferably, the hole sealing glue is mainly permeated along the open pore in the coating and is filled to a depth of more than 500 mu m from the surface of the coating before solidification, so that the problem that the hole sealing glue is insufficient due to the fact that the hole sealing glue is only remained on the surface layer of the coating is avoided, and the hole sealing glue can still effectively seal not less than 95% of open pore in the coating under the condition that the porosity of the thermal spraying coating reaches 20%. Preferably, the curing process of the hole sealing glue is completed at the temperature of not higher than 60 ℃, and the whole curing time is controlled within three days, so that the production efficiency is improved while the hole sealing integrity is ensured Preferably, the thermal spraying coating after hole sealing treatment has the voltage resistance performance st