CN-121976142-A - Pure aluminum electrode coating, preparation method and resistor disc

Abstract

The invention relates to a pure aluminum electrode coating, a preparation method and a resistor disc. The pure aluminum electrode layer is directly deposited on the surface of a matrix made of the carbon ceramic composite material, no intermediate layer is arranged, the thickness of the coating is 30-100 mu m, the porosity is less than 2%, the content of aluminum oxide is not more than 5%, and the bonding strength and the cohesive strength of the pure aluminum electrode layer are both higher than the tensile strength of a carbon Tao Dianzu matrix. The preparation method comprises the steps of cleaning a substrate, sand blasting coarsening, protecting a non-spraying surface, drying and preprocessing powder, fixing a tool, forming a pure aluminum coating by adopting atmospheric plasma spraying, and carrying out subsequent air cooling and surface polishing treatment. By regulating and controlling the spraying power, the spraying distance and the main and auxiliary air flow, the pure aluminum coating with compact structure and low oxidation degree can be obtained. Microstructure and porosity analysis show that the porosity of the coating is obviously lower than that of an electric arc spraying process, the bonding strength can reach about 37.7MPa, and the breakage occurs in a matrix. The coating system of the invention has stable structure, and can obviously improve the conduction performance and the service life of the resistor.

Inventors

• NIE JINGKAI
• HOU DONG
• XU RUOYU
• MA JINXU
• ZHU HUA
• YIN GUILAI
• HE QIANG
• Zhang Chenbofan
• ZHU ZHIXIANG
• QIU NING
• ZHOU MINGYU
• WAN DIMING
• LI YANGLIN
• JI JUN

Assignees

• 中国电力科学研究院有限公司
• 全球能源互联网欧洲研究院
• 国网河南省电力公司
• 国网河南省电力公司电力科学研究院
• 国网江西省电力有限公司电力科学研究院
• 国家电网有限公司

Dates

Publication Date

20260505

Application Date

20251212

Claims (13)

1. 1. The preparation method of the pure aluminum electrode coating is characterized by comprising the following steps of: carrying out surface roughening treatment on the substrate; drying the atomized pure aluminum powder; And (3) adopting an atmospheric plasma spraying process, and controlling the spraying power, the spraying distance, the main air and the auxiliary air flow of the atmospheric plasma spraying process to enable the dried pure aluminum powder to be melted and deposited on the surface of the pretreated substrate, so as to obtain the pure aluminum electrode coating with the interface bonding strength larger than the tensile strength of the substrate.
2. 2. The method for preparing a pure aluminum electrode coating according to claim 1, wherein the substrate is a carbon-ceramic composite substrate, and the carbon-ceramic composite comprises alumina, clay and nano carbon black.
3. 3. The method for preparing the pure aluminum electrode coating according to claim 1, wherein the main gas in the atmospheric plasma spraying process is argon, the flow is 40-50L/min, the auxiliary gas is hydrogen, and the flow is 4-8L/min.
4. 4. The method for preparing a pure aluminum electrode coating according to claim 1, wherein the surface roughening treatment is sand blasting treatment, the pressure range of the sand blasting treatment is 0.3-0.5 MPa, fine-grained corundum sand with more than 100 meshes is used for sand blasting, and/or an included angle between a nozzle and the surface of a substrate is 45-75 degrees.
5. 5. The method for preparing a pure aluminum electrode coating according to claim 1, wherein the particle size range of the aerosolized pure aluminum powder is 40-100 μm.
6. 6. The method for preparing the pure aluminum electrode coating according to claim 1, wherein the drying treatment comprises drying at 60 ℃ for 2-4 hours.
7. 7. The method for preparing the pure aluminum electrode coating according to claim 1, wherein the spraying power of the atmospheric plasma spraying process is 27-33 kW, and the spraying distance is 80-120 mm.
8. 8. A method of producing a pure aluminum electrode coating according to claim 1, wherein the substrate after the atmospheric plasma spray process is air cooled by compressed air and the surface of the coating is ground to remove unmelted particles.
9. 9. A pure aluminum electrode coating, characterized in that the pure aluminum electrode coating is prepared by the preparation method of the pure aluminum electrode coating according to any one of claims 1-8.
10. 10. A pure aluminum electrode coating as recited in claim 9, wherein there is no other tie layer or interlayer transition between the electrode coating and the substrate.
11. 11. A pure aluminum electrode coating as recited in claim 9, wherein the pure aluminum electrode coating has an aluminum oxide content of no more than 5%.
12. 12. A pure aluminum electrode coating as recited in claim 9, wherein the porosity of the pure aluminum electrode coating is less than 2%.
13. 13. A resistor sheet having a pure aluminum electrode coating as claimed in any one of claims 9 to 12 on the end face thereof.

Description

Pure aluminum electrode coating, preparation method and resistor disc Technical Field The invention belongs to the technical field of electrode coatings, and particularly relates to a pure aluminum electrode coating, a preparation method and a resistor disc. Background Carbon Tao Gezha resistor is used as a key protection element in ultra-high voltage and ultra-high voltage transmission systems, and is commonly used in the closing process of a circuit breaker to inhibit transient overvoltage and large impact current which may occur. The carbon Tao Gezha resistor is formed by compounding a ceramic reinforcing phase and a conductive carbon phase, wherein the ceramic phase is usually made of materials such as alumina, kaolin, silicon dioxide and the like so as to provide mechanical strength, high temperature resistance and structural stability of the materials, and the conductive carbon phase such as graphite and carbon black forms a conductive network so that the composite material has reliable electrical performance in a high-temperature electrical environment. To ensure stable operation of carbon Tao Dianzu in high voltage systems, it is necessary to prepare electrode layers at both ends of the resistor sheet to achieve effective connection to external circuits, and apply insulating paint to the sides to ensure the overall electrical isolation of the structure. The existing electrode coating preparation method generally comprises the processes of electric arc spraying, flame spraying, metal slurry coating sintering and the like. These processes are capable of meeting basic requirements in conventional mechanical or general environmental applications, but their performance is still limited in the operating mode of high voltage power transmission equipment. In the thermal spraying process represented by electric arc spraying and flame spraying, the oxidation reaction in the process is obvious, and the deposition speed and the heating uniformity of molten drop particles are limited, so that high proportion of pores and insufficiently melted particles often appear in the coating, and the density of the coating is insufficient. In addition, the coating prepared by the process has limited bonding strength at the interface with carbon Tao Jiti, and the coating is easy to fall off, peel off or local electric contact degradation under the impact load or thermal cycle condition in the service process. On the other hand, the method of forming the electrode layer by sintering after coating with the metal slurry can improve the uniformity of the coating components to a certain extent, but is influenced by the limitation of the slurry components, the narrow sintering temperature window and the thermal expansion characteristic of carbon Tao Jiti, the obtained electrode layer has limited thickness and low density, and the higher requirements on the current flowing capability and the mechanical reliability in an extra-high voltage scene are difficult to meet. Particularly, when the circuit breaker is switched on, the electrode layer can bear huge electric energy transient input, if the coating structure has pores, cracks or combined interface defects, unstable resistance and hot spots can be caused, even rapid failure can be caused, and the reliability and the service life of the whole set of high-voltage equipment are obviously influenced. As high voltage power transmission and transformation equipment is developed to higher voltage level and higher reliability, electrode coating of carbon Tao Gezha resistor is required to have higher density, lower oxidation degree, more reliable interface bonding performance and more stable electric contact characteristic. Although the existing coating preparation technology in the industry can meet part of application, there is still room for improvement in aspects of coating microstructure controllability, thickness uniformity, bond strength improvement, defect suppression and the like. The obtaining of high quality metal coatings, particularly on carbon Tao Jiti, such ceramic-carbon composites, remains one of the long-standing technical challenges in the industry. Therefore, developing a novel electrode coating suitable for carbon Tao Dianzu and a preparation process thereof to improve coating compactness, reduce interface defects and improve service reliability has become an important technical requirement in the field. Disclosure of Invention The invention aims to solve the problems that the density of a carbon Tao Gezha resistance electrode coating is insufficient and the bonding strength is low in the prior art, so that the conduction performance and the service life are influenced. The invention aims at realizing the following technical scheme: The preparation method of the pure aluminum electrode coating comprises the following steps: carrying out surface roughening treatment on the substrate; drying the atomized pure aluminum powder; And (3) adopting an atmospheric plasma spray