Copper alloy gradient carburized layer and preparation method and application thereof

Abstract

The invention discloses a copper alloy gradient carburized layer and a preparation method and application thereof.The preparation method comprises the following steps that a vacuum induction melting or powder metallurgy technology is adopted, active elements are added into copper and copper alloy so that the copper alloy of high-melting-point metal can be generated in situ or compounded to form the copper alloy of the high-melting-point metal, carburizing treatment is conducted on the copper alloy of the high-melting-point metal, and the copper alloy of the high-melting-point metal is obtained. Therefore, an anti-bonding and high-wear-resistance gradient carburized layer is formed on the surface of the copper alloy. According to the method, active elements are introduced into copper and a copper alloy, high-purity acetylene gas serves as a carbon source, carbon and the active elements react on the surface of the alloy under the action of high temperature, the active elements in the copper alloy continuously migrate to the surface, and then a surface gradient carburized layer with the active element content concentration gradient and the hardness gradient is formed; the problem that a carburized layer is difficult to form due to the fact that copper and carbon do not react is avoided, the subsequent carburizing treatment and preparation process is simple and controllable, convenient to operate and low in cost, operability is also achieved for actual workpieces with complex shapes, and therefore practicability is high.

Description

Technical Field

[0001] This invention relates to the field of copper alloy technology, and in particular to a gradient carburized layer of copper alloy, its preparation method, and its application. Background Technology

[0002] Electrical contacts are components in electrical equipment that connect, disconnect, and continuously carry current through mechanical action. They are widely used in circuit breakers, relays, contactors, and other switching elements in various electrical systems. To achieve good breaking performance, the materials used to manufacture electrical contacts generally need to meet the following requirements: (1) good electrical and thermal conductivity and low contact resistance; (2) good resistance to mechanical wear and arc corrosion; (3) good resistance to welding. Currently, the most widely used electrical contact materials are Ag-based materials and Cu-based materials. To reduce costs, the current trend is to replace Ag-based contacts with Cu-based contacts. In practical applications, copper alloy contacts suffer from severe adhesion and wear under high temperatures, resulting in poor anti-adhesion properties. Therefore, there is an urgent need for a copper alloy gradient carburizing layer that can prepare electrical contacts with good anti-adhesion properties, wear resistance, and low cost, as well as its preparation method and application. Summary of the Invention

[0003] This solution addresses the problems and needs raised above by proposing a gradient carburizing layer for copper alloys, its preparation method, and its application. The above-mentioned technical objectives are achieved by adopting the following technical features, and several other technical benefits are also brought about.

[0004] One object of the present invention is to provide a method for preparing a gradient carburized layer on a copper alloy, comprising the following steps: By employing vacuum induction melting or powder metallurgy processes, active elements are added to copper and copper alloys to generate or composite high-melting-point metal copper alloys in situ. The high-melting-point metal copper alloys are then subjected to carburizing treatment to form an anti-adhesion, highly wear-resistant gradient carburized layer on the surface of the copper alloy.

[0005] In addition, the copper alloy gradient carburized layer, its preparation method, and its application according to the present invention may also have the following technical features: In one example of the present invention, adding reactive elements to copper and copper alloys to generate or composite high-melting-point metal copper alloys in situ includes the following: S10: Polish the copper alloy with a high melting point to remove the surface oxides, clean it, blow it with cold air, and then dry it. S20: The active elements are prepared as gold master alloys according to the mass percentage, and then heated and smelted in a vacuum induction furnace. After all the raw materials are melted, the sample is rapidly cooled and taken out to obtain a copper alloy with a high melting point. Alternatively, the active elements are prepared as powders according to the mass percentage, ball milled first, and then rapidly sintered in a vacuum sintering furnace after uniform mixing to obtain a copper alloy with a high melting point.

[0006] In one example of the present invention, in step S10, the alloy surface is polished with 80-1500# SiC sandpaper to remove surface oxides, ultrasonically cleaned in alcohol for 10-15 minutes, dried with cold air, and then placed in a drying oven to dry.

[0007] In one example of the present invention, carburizing a copper alloy with a high melting point specifically includes the following steps: W10: Remove the oxide layer from the high-melting-point copper alloy, clean it, dry it with cold air, and then dry it. W20: The above copper alloy is placed in a high-temperature carburizing furnace, and carbon source gas is used. After adjusting its flow rate, it is heated to a stable temperature and then held at that temperature to obtain a carburized layer on the surface of the copper alloy.

[0008] In one example of the present invention, in step W10, the copper alloy of high melting point metal is polished to remove the oxide layer, ultrasonically cleaned in alcohol for 10-15 minutes, dried with cold air, and then placed in a drying oven to dry.

[0009] In one example of the present invention, in step W20, the copper alloy sample is placed in a high-temperature carburizing furnace, high-purity acetylene gas is used as the carbon source, the flow rate is adjusted to 30-200 ml / min, and then heated to 800-820°C and held for 8-10 hours to form a carburized layer on the surface of the copper alloy.

[0010] In one example of the invention, the reactive elements include chromium, titanium, and tungsten.

[0011] Another objective of this invention is to provide a copper alloy gradient carburizing layer, which is prepared using the method described above.

[0012] Another object of the present invention is to provide an electrical contact comprising a conductive material, said conductive material comprising the aforementioned copper alloy gradient carburized layer.

[0013] Another object of the present invention is to provide an electrical switching element comprising the electrical contacts as described above.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention introduces active elements into copper and copper alloys, using high-purity acetylene gas as a carbon source. Under high temperature, carbon reacts with the active elements on the alloy surface, causing the active elements in the copper alloy to continuously migrate to the surface, thereby forming a surface gradient carburized layer with a gradient in the concentration and hardness of the active elements. This avoids the problem of copper and carbon not reacting, which makes it difficult to form a carburized layer. The subsequent carburizing process is simple, controllable, easy to operate, and low in cost. It is also operable for actual workpieces with complex shapes, thus having strong practicality.

[0015] 2. The gradient carburized layer obtained by this invention is dense and continuous, not prone to cracking, has a high melting point, good oxidation resistance, good anti-sticking properties, good corrosion resistance, and is widely used.

[0016] The preferred embodiments of the invention will be described in more detail below with reference to the accompanying drawings, so as to facilitate an understanding of the features and advantages of the invention. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly described below. The drawings are merely illustrative of some embodiments of the present invention and are not intended to limit the scope of the present invention to all embodiments.

[0018] Figure 1 EDS image of the cross-section of the carburized layer of CuCr30 alloy in Example 1; Figure 2 This is a TEM image of the carburized layer of the CuCr40 alloy in Example 2; Figure 3 This is a comparison of the surface hardness of CuCr25 and CuCr40 alloys before and after carburizing in Example 2. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. The same reference numerals in the drawings represent the same components. It should be noted that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, “an” or “a” and similar terms do not necessarily indicate a quantity limitation. Terms such as “comprising” or “including” mean that the element or object preceding the word encompasses the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as “connected” or “linked” are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; these relative positional relationships may change accordingly when the absolute position of the described object changes.

[0021] In practical applications, copper alloy contacts suffer from severe adhesive wear under high temperatures and exhibit poor anti-adhesion properties. Preparing a shallow carburized layer is a low-cost, high-performance, and effective way to improve the anti-adhesion and wear resistance of copper alloys. Cu, as an inert element, neither reacts with nor wets carbon (C). Adding elements such as Cr, Ti, and W, which readily react with carbon or have good wettability with carbon, to Cu to form a copper alloy helps improve the wettability between the alloy and carbon, forming a shallow nano-carbide layer, which significantly improves the melting point, wear resistance, and anti-adhesion properties of the copper alloy.

[0022] A method for preparing a gradient carburized layer of a copper alloy according to a first aspect of the present invention includes the following steps: By employing vacuum induction melting or powder metallurgy processes, active elements are added to copper and copper alloys to generate or composite high-melting-point metal copper alloys in situ. The high-melting-point metal copper alloys are then subjected to carburizing treatment to form an anti-adhesion, highly wear-resistant gradient carburized layer on the surface of the copper alloy.

[0023] This method introduces active elements into copper and copper alloys, using high-purity acetylene gas as a carbon source. Under high temperature, carbon reacts with the active elements on the alloy surface, causing the active elements in the copper alloy to continuously migrate to the surface, thereby forming a surface gradient carburized layer with a gradient in the concentration and hardness of the active elements. This avoids the problem of copper and carbon not reacting, which makes it difficult to form a carburized layer. The subsequent carburizing process is simple and controllable, easy to operate, and low in cost. It is also operable for actual workpieces with complex shapes, thus having strong practicality.

[0024] The gradient carburized layer obtained by this method is dense and continuous, not prone to cracking, has a high melting point, and is resistant to oxidation, adhesion, and corrosion, making it widely applicable.

[0025] In one example of the present invention, adding reactive elements to copper and copper alloys to generate or composite high-melting-point metal copper alloys in situ includes the following: S10: Polish the copper alloy with a high melting point to remove the surface oxides, clean it, blow it with cold air, and then dry it. S20: The active elements are prepared as gold master alloys according to the mass percentage, and then heated and smelted in a vacuum induction furnace. After all the raw materials are melted, the sample is rapidly cooled and taken out to obtain a copper alloy with a high melting point. Alternatively, the active elements are prepared as powders according to the mass percentage, ball milled first, and then rapidly sintered in a vacuum sintering furnace after uniform mixing to obtain a copper alloy with a high melting point.

[0026] In one example of the present invention, in step S10, the alloy surface is polished with 80-1500# SiC sandpaper to remove surface oxides, ultrasonically cleaned in alcohol for 10-15 minutes, dried with cold air, and then placed in a drying oven to dry.

[0027] In one example of the present invention, carburizing a copper alloy with a high melting point specifically includes the following steps: W10: Remove the oxide layer from the high-melting-point copper alloy, clean it, dry it with cold air, and then dry it. W20: The above copper alloy is placed in a high-temperature carburizing furnace, and carbon source gas is used. After adjusting its flow rate, it is heated to a stable temperature and then held at that temperature to obtain a carburized layer on the surface of the copper alloy.

[0028] In one example of the present invention, in step W10, the copper alloy of high melting point metal is polished to remove the oxide layer, ultrasonically cleaned in alcohol for 10-15 minutes, dried with cold air, and then placed in a drying oven to dry.

[0029] In one example of the present invention, in step W20, the copper alloy sample is placed in a high-temperature carburizing furnace, high-purity acetylene gas is used as the carbon source, the flow rate is adjusted to 30-200 ml / min, and then heated to 800-820°C and held for 8-10 hours to form a carburized layer on the surface of the copper alloy.

[0030] In one example of the invention, the active elements include chromium (Cr), titanium (Ti), and tungsten (W).

[0031] According to a second aspect of the present invention, a copper alloy gradient carburizing layer is prepared by the method described above for preparing a copper alloy gradient carburizing layer.

[0032] According to a third aspect of the present invention, an electrical contact includes a conductive material, said conductive material comprising the aforementioned copper alloy gradient carburized layer.

[0033] An electrical switching element according to a fourth aspect of the present invention includes an electrical contact as described above. Specific Implementation Example 1: Step 1, Introduction and smelting of active elements: (a) The surface oxides of the copper alloy were removed by polishing with 80-1500# SiC sandpaper, ultrasonically cleaned in alcohol for 15 minutes, dried with cold air, and then dried in a drying oven; (b) The raw materials were weighed according to the mass percentage of 30% Cr-70% Cu, and heated and smelted in a vacuum induction furnace. After all the raw materials were melted, they were rapidly cooled and the sample was taken out, thus completing the preparation of a high melting point copper-chromium alloy. Step 2: Preparation of carbide carburized layer: (a) Polish the copper-chromium alloy obtained in step 1 to remove the oxide layer, ultrasonically clean it in alcohol for 15 min, blow it dry with cold air, and then dry it in a drying oven; (b) Place the alloy sample in a high-temperature carburizing furnace, use high-purity acetylene gas as the carbon source, adjust its flow rate to 100 ml / min, then heat it to 820℃, hold it for 8 h, and a high-melting-point metallic copper alloy with a surface carburized layer is formed.

[0035] Figure 1 The image shows the EDS diagram of the gradient carburized layer of the CuCr30 alloy in Example 1, indicating that carbon and chromium have an affinity for each other, forming a dense and continuous gradient carburized layer with a thickness of about 7 μm on the alloy surface. Specific Implementation Example 2: The first step, the introduction and sintering of active elements: (a) The surface oxides of the copper alloy are removed by polishing with 80-1500# SiC sandpaper, ultrasonically cleaned in alcohol for 15 minutes, dried with cold air, and then dried in a drying oven; (b) The materials are weighed according to the mass percentages of 25%Cr-75%Cu and 40%Cr-60%Cu, ball milled first, and after uniform mixing, they are placed in a vacuum sintering furnace for rapid sintering to obtain a copper alloy with a high melting point metal.

[0037] Step 2: Preparation of carbide carburized layer: (a) Polish the copper-chromium alloy obtained in step 1 to remove the oxide layer, ultrasonically clean it in alcohol for 15 min, blow it dry with cold air, and then dry it in a drying oven; (b) Place the alloy sample in a high-temperature carburizing furnace, use high-purity acetylene gas as the carbon source, adjust its flow rate to 100 ml / min, then heat it to 820℃, hold it for 8 h, and a high-melting-point metallic copper alloy with a surface carburized layer is formed.

[0038] The microstructure and phase evolution of the carburized layer of CuCr40 alloy were characterized in detail using transmission electron microscopy (TEM), such as... Figure 2 As shown. Figure 2 a shows dislocations in the alloy's microstructure; the presence of dislocations can improve the mechanical properties of the composite material. Combined with... Figure 2 The bright-field image of bf, calibrated with selected area electron diffraction (SAED), confirms that the black area is a copper matrix and the gray area is Cr particles with a particle size of less than 200 nm. 23 C6 particles. The physical properties of the CuCr alloy obtained in Example 2 of this invention before and after carburizing are as follows: Figure 3 As shown. Specific Implementation Example 3: The first step, the introduction and sintering of active elements: (a) The surface oxides of the copper alloy are removed by polishing with 80-1500# SiC sandpaper, ultrasonically cleaned in alcohol for 15 minutes, dried with cold air, and then dried in a drying oven; (b) According to the actual application, the materials are weighed and mixed according to the mass percentage of 25%Cr-75%Cu, 40%W-40%Cu, and 10%Ti-90%Cu. The materials are first ball-milled, and after the powder is evenly mixed, it is put into a vacuum sintering furnace for rapid sintering to obtain a copper alloy with a high melting point metal.

[0040] Step 2: Preparation of carbide carburized layer: (a) Polish the copper alloy obtained in step 1 to remove the oxide layer, ultrasonically clean it in alcohol for 15 min, blow it dry with cold air, and then dry it in a drying oven; (b) Take half of the copper alloy sample and place it in a high-temperature carburizing furnace, use high-purity acetylene gas as carbon source, adjust its flow rate to 100 ml / min, then heat it to 820℃, hold it for 8 h, and a high melting point metallic copper alloy with a surface carburized layer is formed.

[0041] Three copper alloys of different types (labeled as 1#, 2#, and 3#) were selected for electrical life testing under high-current capacitive load conditions. The test results are shown in Table 1. It can be clearly seen that the effective anti-adhesion count of CuCr25, CuW40, and CuTi10 alloys increased significantly after carburizing compared to before carburizing.

[0042] Table 1 shows the electrical lifetime of different alloys before and after carburization under capacitive load. This method employs a stepwise carburizing approach, first adding reactive elements Cr, Ti, and W, followed by high-temperature carburizing. This ensures the preferential formation of a high-melting-point copper alloy with excellent wear resistance. Then, by adjusting the carburizing time, diffusion time, and carbon potential, heating and holding in an activated carbon medium allows chromium within the copper alloy to attract active carbon atoms, forming a carburized layer with a certain thickness and carbon concentration gradient on the surface. This layer exhibits anti-adhesion, wear resistance, and corrosion resistance. This invention is suitable for preparing gradient carburized layers on copper alloy workpieces with complex structures. The carburized layer bonds tightly to the substrate, and the preparation method is simple, low-cost, and easy to implement.

[0043] The foregoing description, with reference to preferred embodiments, details exemplary embodiments of the copper alloy gradient carburizing layer, its preparation method, and its application proposed in this invention. However, those skilled in the art will understand that various modifications and alterations can be made to the above specific embodiments without departing from the concept of this invention, and various combinations can be made to the various technical features and structures proposed in this invention without exceeding the protection scope of this invention, which is determined by the appended claims.

Claims

1. A method for preparing a gradient carburized layer on a copper alloy, characterized in that, Includes the following steps: By employing vacuum induction melting or powder metallurgy processes, active elements are added to copper and copper alloys to generate or composite high-melting-point copper alloys in situ. The high-melting-point copper alloys are then subjected to carburizing treatment to form an anti-adhesion, highly wear-resistant gradient carburized layer on the surface of the copper alloy.

2. The method for preparing a gradient carburized layer of copper alloy according to claim 1, characterized in that, Adding reactive elements to copper and copper alloys to form high-melting-point copper alloys in situ or through composite formation includes the following: S10: Polish the copper alloy with a high melting point to remove the surface oxides, clean it, blow it with cold air, and then dry it. S20: The active elements are prepared as gold master alloys according to the mass percentage, and then heated and smelted in a vacuum induction furnace. After all the raw materials are melted, the sample is rapidly cooled and taken out to obtain a copper alloy with a high melting point. Alternatively, the active elements are prepared as powders according to the mass percentage, ball milled first, and then rapidly sintered in a vacuum sintering furnace after uniform mixing to obtain a copper alloy with a high melting point.

3. The method for preparing a gradient carburized layer of copper alloy according to claim 2, characterized in that, In step S10, the alloy surface is polished with 80-1500# SiC sandpaper to remove surface oxides, ultrasonically cleaned in alcohol for 10-15 minutes, dried with cold air, and then placed in a drying oven to dry.

4. The method for preparing a gradient carburized layer of copper alloy according to claim 1, characterized in that, Carburizing of copper alloys, which are high-melting-point metals, specifically includes the following steps: W10: Remove the oxide layer from the high-melting-point copper alloy, clean it, dry it with cold air, and then dry it. W20: The above copper alloy is placed in a high-temperature carburizing furnace, and carbon source gas is used. After adjusting its flow rate, it is heated to a stable temperature and then held at that temperature to obtain a carburized layer on the surface of the copper alloy.

5. The method for preparing a gradient carburized layer of copper alloy according to claim 4, characterized in that, In step W10, the high-melting-point copper alloy is polished to remove the oxide layer, ultrasonically cleaned in alcohol for 10-15 minutes, dried with cold air, and then placed in a drying oven to dry.

6. The method for preparing a gradient carburized layer of copper alloy according to claim 4, characterized in that, In step W20, the copper alloy sample is placed in a high-temperature carburizing furnace, using high-purity acetylene gas as the carbon source, and its flow rate is adjusted to 30-200 ml / min. Then, it is heated to 800-820°C and held for 8-10 hours to form a carburized layer on the surface of the copper alloy.

7. The method for preparing a gradient carburized layer of copper alloy according to claim 1, characterized in that, The active elements include chromium, titanium, and tungsten.

8. A gradient carburized layer of copper alloy, characterized in that, The copper alloy gradient carburized layer was prepared using the preparation method described in any one of claims 1 to 7.

9. An electrical contact, characterized in that, It includes a conductive material, wherein the conductive material includes the copper alloy gradient carburized layer as described in claim 8.

10. An electrical switching element, characterized in that, Includes the electrical contact as described in claim 9.

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