Copper-chromium contact material with honeycomb biomimetic structure chromium skeleton, preparation method and application thereof

Abstract

The present application belongs to the technical field of contact materials, and in particular relates to a copper-chromium contact material having a honeycomb biomimetic chromium skeleton, a preparation method, and an application thereof; the copper-chromium contact material provided by the present application has a honeycomb biomimetic chromium skeleton, and a copper matrix is ​​filled in the honeycomb biomimetic chromium skeleton. The honeycomb biomimetic chromium skeleton is a directional structure, which can avoid the arc aggregation phenomenon caused by the random non-directional distribution of the chromium skeleton, and can also improve its thermal conductivity and electrical conductivity, thereby improving the performance of the copper-chromium contact material, thereby solving the technical problem of low performance of the copper-chromium contact material in the prior art.

Description

Technical Field

[0001] The present application belongs to the technical field of contact materials, and in particular relates to a copper-chromium contact material having a honeycomb bionic structure chromium skeleton, a preparation method, and an application thereof. Background Art

[0002] Vacuum circuit breakers have the advantages of small size, light weight, suitability for frequent operation, and arc extinguishing without maintenance. They are currently widely used in electrical systems. Contact materials are the contact components of vacuum circuit breakers. Their quality and performance directly affect the performance and stability of vacuum circuit breakers, which may affect the normal operation of the entire electrical system.

[0003] As vacuum circuit breakers increase from 12kV to 126kV and then to 252kV, the primary technical challenge is to enhance the insulation withstand voltage capability of vacuum contacts. Contact material is one of the key factors determining the insulation withstand voltage capability of vacuum circuit breakers. Ideal vacuum circuit breaker contact materials should have large breaking current capability, high voltage resistance, reliable resistance to welding, high electrical and thermal conductivity, low arc burn rate, and low current cutoff value. Copper-chromium alloy combines the advantages of copper's high electrical and thermal conductivity with chromium's high melting point, high hardness, and oxygen affinity, and is currently the main contact material used for vacuum circuit breakers.

[0004] However, the current copper-chromium contact materials are mainly obtained by mixing copper and chromium through processes such as vacuum casting, vacuum infiltration, arc melting and mixed powder metallurgy. The copper and chromium in the copper-chromium contact materials do not have a specific preferential directional distribution in space, which affects the electrical conductivity and heat dissipation properties of the copper-chromium contact materials. The performance of the copper-chromium contact materials is not high enough and it is difficult to meet the requirements of higher-level vacuum circuit breakers.

[0005] Natural biomaterials in nature exhibit unique functional properties due to their ingenious microstructural laws, providing important inspiration for the development of high-performance bionic materials. Summary of the Invention

[0006] In view of this, the present application provides a copper-chromium contact material with a honeycomb bionic structure chromium skeleton, a preparation method and an application thereof, to solve the technical problem of low performance of copper-chromium contact materials in the prior art.

[0007] The first aspect of the present application provides a copper-chromium contact material having a honeycomb biomimetic chromium skeleton, comprising: a honeycomb structured chromium skeleton, a copper substrate;

[0008] The chromium skeleton of the honeycomb structure is embedded in the copper matrix.

[0009] Preferably, the mass ratio of the chromium skeleton of the honeycomb structure to the copper matrix is ​​20-30:70-80.

[0010] Preferably, the chromium skeleton of the honeycomb structure comprises: 3 to 7 single-cell structures;

[0011] One of the single-room structures comprises 2 to 5 layers of chrome sheets in the shape of hollow regular prisms, wherein the diagonal lines of the cross sections of adjacent chrome sheets in the shape of hollow regular prisms partially overlap and have the same center.

[0012] Preferably, in the single-chamber structure, the spacing between adjacent hollow regular prism-shaped chromium sheets is 0.5-2 μm.

[0013] Preferably, the thickness of the hollow regular prism-shaped chromium sheet layer is 0.5-2 μm, and the side length is 5-10 μm.

[0014] Preferably, the shape of the hollow regular prism is selected from a hollow regular triangular prism, a hollow regular quadrangular prism or a hollow regular hexagonal prism.

[0015] A second aspect of the present application provides a method for preparing a copper-chromium contact material having a honeycomb biomimetic chromium skeleton, the preparation method comprising the steps of:

[0016] Step S1: loading chromium powder into a 3D printing device and establishing a 3D model of a chromium skeleton, and performing 3D printing to obtain a chromium skeleton with a honeycomb structure;

[0017] Step S2: placing the chromium skeleton with a honeycomb structure in a copper-chromium contact material mold, infiltrating the pores of the chromium skeleton with heated and melted copper powder into the pores of the chromium skeleton with a honeycomb structure, and obtaining a copper-chromium contact material with a chromium skeleton with a honeycomb biomimetic structure after cooling.

[0018] Preferably, in step S1, the 3D printing equipment is selected from direct metal laser sintering equipment, electron beam melting equipment or selective laser sintering equipment.

[0019] A third aspect of the present application provides an application of a copper-chromium contact material having a honeycomb biomimetic structure chromium skeleton in a vacuum circuit breaker.

[0020] A fourth aspect of the present application provides a vacuum circuit breaker, comprising a vacuum interrupter and an operating mechanism;

[0021] The operating mechanism is used to control the contact assembly in the vacuum interrupter to open or close the circuit breaker;

[0022] The contact assembly includes the copper-chromium contact material having a honeycomb biomimetic chromium skeleton as described in the first aspect.

[0023] In summary, the present application provides a copper-chromium contact material with a honeycomb bionic structure chromium skeleton, a preparation method, and an application. The copper-chromium contact material with a honeycomb bionic structure chromium skeleton provided by the present application first obtains a honeycomb structure chromium skeleton by 3D printing, and then the copper matrix is ​​buried in the honeycomb structure chromium skeleton by a solution infiltration process. Compared with the random non-directional distribution chromium skeleton, the honeycomb bionic structure chromium skeleton set in the copper-chromium contact material provided by the present application can avoid arc aggregation when electrical breakdown occurs, and can also improve its thermal conductivity and electrical conductivity, thereby improving the performance of the copper-chromium contact material and solving the technical problem of low performance of the copper-chromium contact material in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0025] Figure 1 Schematic diagram of the cross section of a honeycomb biomimetic chromium skeleton comprising seven single-cell structures;

[0026] Figure 2 A schematic cross-sectional view of a single-cell structure in a honeycomb biomimetic chromium skeleton comprising seven single-cell structures;

[0027] Figure 3 A schematic cross-sectional view of a copper-chromium contact material having a honeycomb biomimetic chromium skeleton provided in Example 1 of the present application;

[0028] Figure 4 A schematic cross-sectional view of a single-chamber structure in the copper-chromium contact material having a honeycomb biomimetic chromium skeleton provided in Example 1 of the present application;

[0029] Figure 5 This is a schematic diagram of a model of different chromium skeleton distributions in the copper-chromium contact material described in the embodiment, constructed using the simulation software Comsol for Experimental Example 1;

[0030] Figure 6 This is the thermal stress simulation result diagram of the random non-directional distribution of chromium skeleton in the copper-chromium contact material built by the simulation software COMSO in Experimental Example 1;

[0031] Figure 7 This is the thermal stress simulation result diagram of the directional distribution of the hollow regular quadrangular prisms of the chromium skeleton in the copper-chromium contact material built using the simulation software Comsol in Experimental Example 1;

[0032] Figure 8This is the thermal stress simulation result diagram of the directional distribution of hollow hexagonal prisms in the copper-chromium contact material built using the simulation software Comsol in Experimental Example 1. DETAILED DESCRIPTION

[0033] The present application provides a copper-chromium contact material with a honeycomb biomimetic structure chromium skeleton, a preparation method and an application thereof, which are used to solve the technical problem of low performance of copper-chromium contact materials in the prior art.

[0034] The following will clearly and completely describe the technical solution of this application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0035] In view of the fact that the chromium skeleton in the current copper-chromium contact material is randomly and non-directionally distributed, and there is no preferential directional distribution, which affects the performance of the chromium contact material; the present application provides a copper-chromium contact material with a honeycomb bionic structure chromium skeleton, a preparation method and application; the composition of the copper-chromium contact material with a honeycomb bionic structure chromium skeleton provided by the present application includes: a honeycomb structure chromium skeleton, a copper matrix, and the honeycomb structure chromium skeleton is embedded in the copper matrix; after the copper-chromium contact material provided by the present application is used in a vacuum circuit breaker, when an electrical breakdown occurs, the first breakdown phase will occur at the chromium skeleton, and the arc root will follow the chromium skeleton of the honeycomb structure in the copper-chromium contact material. The frame moves quickly, which effectively avoids the arc gathering and the arc gathering phenomenon caused by the random non-directional distribution of the chromium skeleton in the traditional copper-chromium contact material. At the same time, the bionic structure of the honeycomb structure has the advantages of large structural heat dissipation specific surface area and high average convection heat transfer coefficient, which makes the chromium skeleton of the honeycomb structure in the copper-chromium contact material have excellent thermal diffusion performance and thermal stability, avoiding the defect of poor thermal conductivity of the random non-directional distribution of the chromium skeleton in the traditional copper-chromium contact material. The chromium skeleton of the honeycomb structure is also beneficial to improving the electrical conductivity and anti-welding performance of the copper-chromium contact material, thereby improving the performance of the copper-chromium contact material.

[0036] At the same time, the specific composition of the chromium skeleton of the honeycomb structure in the copper-chromium contact material provided in this application is composed of 3 to 7 single-room structures; the single-room structure includes chromium sheets in the shape of hollow regular prisms, the number of chromium sheets is 2 to 5 layers, and the cross-sectional diagonals of the hollow regular prism-shaped chromium sheets partially overlap and have the same center; wherein, a schematic diagram of the chromium skeleton of the honeycomb biomimetic structure including seven single-room structures is shown as follows Figure 1 As shown, the single room structure is as follows Figure 2 As shown in the figure, the structure diagram of the copper-chromium contact material with a honeycomb biomimetic chromium skeleton with three single-room structures is shown in the figure. Figure 3 As shown, it includes three single-room honeycomb biomimetic chromium skeletons and a copper matrix. The single-room structure is as follows Figure 4shown.

[0037] As for the distance between adjacent hollow regular prism-shaped chromium sheets, the present application sets the spacing to be 0.5-2 μm, the thickness of the chromium sheet to be 0.5-2 μm, and the side length to be 5-10 μm.

[0038] For the hollow regular prism shape of the sheet in the single-room structure, the present application can select a chromium sheet in the shape of a hollow regular triangular prism, a hollow regular quadrangular prism or a hollow hexagonal regular prism; preferably, the chromium sheet in the shape of a hollow hexagonal regular prism. Compared with the sheets of hollow regular triangular prism and hollow regular quadrangular prism, the chromium sheet in the shape of a hollow hexagonal regular prism is beneficial to reducing the resistance of the fluid network system and can also reduce the local flow dead zone formed by the corners / right angles of the hollow regular triangular prism / hollow regular quadrangular prism, thereby improving the electrical conductivity / heat exchange efficiency, and further improving the electrical conductivity / thermal conductivity and other properties of the copper-chromium contact material.

[0039] For the preparation method of the copper-chromium contact material with a honeycomb biomimetic structure chromium skeleton provided in this application, the honeycomb structure chromium skeleton is first prepared by a 3D printing process, and then the copper matrix is ​​filled into the pores of the honeycomb structure chromium skeleton by a vacuum infiltration process; wherein, the 3D printing process selects direct metal laser sintering equipment, electron beam melting molding equipment or selective laser sintering equipment, etc. which can be used for metal material 3D printing equipment. The vacuum infiltration process is to melt the copper powder and then infiltrate the chromium skeleton, fill the skeleton pores with copper melt, and after cooling to room temperature, the copper-chromium contact material with a honeycomb biomimetic structure chromium skeleton can be obtained.

[0040] Example 1

[0041] Example 1 of the present application provides a method for preparing a copper-chromium contact material having a honeycomb biomimetic chromium skeleton, the preparation method comprising: a step of 3D printing the chromium skeleton of the honeycomb structure, and a step of vacuum infiltration to fill the pores of the chromium skeleton of the honeycomb structure with a copper matrix.

[0042] The steps of 3D printing the chromium skeleton of the honeycomb structure include: loading chromium powder into a direct metal laser sintering device and modeling the chromium skeleton of the honeycomb structure in the device according to the designed structure, evacuating the device to below 500 Pa, and performing 3D printing to obtain the chromium skeleton of the honeycomb structure; wherein the designed chromium skeleton of the honeycomb structure is a 3-cell structure, each of which includes 2 layers of chromium sheets in the shape of hollow regular hexagonal prisms, and its structure is as follows Figure 3-4 As shown in the figure, the thickness of the chromium flake layer is 1μm, the side length of the outer layer is 10μm, and the spacing between adjacent chromium flake layers is 0.5μm; the 3D printing parameters are: laser power is 150W, scanning speed is 100mm / s, and laser beam diameter is 100nm.

[0043] The step of vacuum infiltration to fill the pores of the chromium skeleton of the honeycomb structure with a copper matrix includes: placing the chromium skeleton of the honeycomb structure in a hollow cylindrical copper-chromium contact material graphite mold, and placing an excess infiltration pure copper block on the chromium skeleton, then placing the graphite mold in a sintering furnace, heating to 1400°C at a rate of 10°C / min under a vacuum condition of -0.05MPa, keeping the temperature for 30 minutes, infiltrating the chromium skeleton with molten metal copper, filling the skeleton pores with copper melt in the graphite mold, so that the chromium skeleton of the honeycomb structure is embedded in the copper matrix, and then cooling to room temperature at a rate of 5°C / min to obtain a copper-chromium contact material with a honeycomb biomimetic chromium skeleton, wherein the mass ratio of Cu to Cr in the copper-chromium contact material is 75:25.

[0044] Experimental Example 1

[0045] The experimental example of this application uses the simulation software Comsol to build a model diagram of different chromium skeleton distribution in copper-chromium contact materials, and evaluates its thermal performance through simulation experiments. The three models established are as follows Figure 3 As shown, Figure 5 Figure (a) shows the model of random non-directional distribution of chromium skeleton, Figure (b) shows the model of directional distribution of chromium skeleton with regular tetrahedron, and Figure (c) shows the model of directional distribution of chromium skeleton with regular hexagonal prism.

[0046] The simulation experiment process is the thermal stress distribution when the room temperature rises to the arc temperature of 3000K. The results of the simulation experiment are as follows: Figure 6-8 As shown, from Figure 6-8 It can be seen that the minimum thermal stress of the model with random non-directional distribution of chromium skeleton is 0.00583μm, and the maximum thermal stress is 0.39414μm, while the minimum thermal stress of the model with directional distribution of chromium skeleton regular tetrahedron is 0.04107μm, and the maximum thermal stress is 0.23833μm, and the minimum thermal stress of the model with directional distribution of chromium skeleton regular hexagonal prism is 0.02686μm, and the maximum thermal stress is 0.24130μm; From the results of this simulation experiment, it can be seen that the model with directional distribution of chromium skeleton regular tetrahedron and the model with directional distribution of chromium skeleton regular hexagonal prism have the same thermal stress as the model with random non-directional distribution of chromium skeleton. The thermal performance is better than that of the model with random non-directional distribution of the chromium skeleton, and it has superior thermal stability and thermal diffusion capacity. This indirectly verifies that compared with the random non-directional chromium skeleton, the copper-chromium contact material provided by the present application has better thermal diffusion performance and thermal stability due to the directionally distributed honeycomb bionic structure chromium skeleton; at the same time, the thermal performance of the model with a directional distribution of the chromium skeleton with regular hexagonal prisms is better, which indirectly shows that compared with the chromium skeleton with a directionally distributed regular quadrangular prism, the chromium skeleton with a directionally distributed regular hexagonal prism can reduce the local flow dead zone formed by right angles, reduce resistance, and thus have better thermal stability and thermal diffusion capacity.

[0047] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A copper-chromium contact material with a honeycomb biomimetic chromium skeleton, characterized in that: include: Honeycomb structure with chromium skeleton and copper matrix; The chromium skeleton of the honeycomb structure is embedded in the copper matrix; The chromium skeleton of the honeycomb structure includes: 3 to 7 single-cell structures; One of the single-room structures comprises: 2 to 5 layers of chrome sheets in the shape of hollow regular prisms, wherein the diagonal lines of the cross sections of adjacent chrome sheets in the shape of hollow regular prisms partially overlap and have the same center; The hollow regular prism is selected from a hollow regular quadrangular prism or a hollow regular hexagonal prism; The spacing between adjacent hollow regular prism-shaped chromium sheets is 0.5 to 2 μm; The thickness of the hollow regular prism-shaped chromium sheet layer is 0.5 to 2 μm, and the side length is 5 to 10 μm.

2. The copper-chromium contact material with a honeycomb biomimetic chromium skeleton according to claim 1, characterized in that: The mass ratio of the chromium skeleton of the honeycomb structure to the copper matrix is ​​20-30:70-80.

3. The method for preparing a copper-chromium contact material having a honeycomb biomimetic chromium skeleton according to any one of claims 1 to 2, characterized in that: Including steps: Step S1: loading chromium powder into a 3D printing device and establishing a 3D model of a chromium skeleton, and performing 3D printing to obtain a chromium skeleton with a honeycomb structure; Step S2: placing the chromium skeleton with a honeycomb structure in a copper-chromium contact material mold, infiltrating the pores of the chromium skeleton with heated and melted copper powder into the pores of the chromium skeleton with a honeycomb structure, and obtaining a copper-chromium contact material with a chromium skeleton with a honeycomb biomimetic structure after cooling.

4. The method for preparing a copper-chromium contact material having a honeycomb biomimetic chromium skeleton according to claim 3, characterized in that: The 3D printing device is selected from direct metal laser sintering equipment, electron beam melting equipment or selective laser sintering equipment.

5. Use of the copper-chromium contact material having a honeycomb biomimetic chromium skeleton according to any one of claims 1 to 2 in a vacuum circuit breaker.

6. A vacuum circuit breaker, characterized in that: Including vacuum interrupter and operating mechanism; The operating mechanism is used to control the static contact material and the moving contact material in the vacuum interrupter to open or close the circuit breaker; The static contact material and the dynamic contact material are selected from the copper-chromium contact material having a honeycomb biomimetic chromium skeleton as described in any one of claims 1 to 2.

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