Silver tin oxide electric contact material based on oxide skeleton and high-entropy alloy and preparation method of silver tin oxide electric contact material

Abstract

The invention provides a silver tin oxide electrical contact material based on an oxide skeleton and a high-entropy alloy and a preparation method thereof.The method comprises the steps that a silver ingot, a tin ingot and other metal additives are melted and subjected to 3D printing to obtain a blank of a needed profile, then oxidation and surface pickling are conducted, so that a porous oxide skeleton is formed on the surface layer of the blank, and then the silver tin oxide electrical contact material is obtained; the surface of the porous oxide skeleton is subjected to high-entropy alloy selective laser melting treatment, and finally the silver tin oxide electric contact material is obtained. The strength of an oxide skeleton is ensured by adopting an oxide skeleton in-situ generation method, and the skeleton and a high-entropy alloy are subjected to selective laser melting to modify and reinforce a silver matrix, so that a working layer of a contact prepared from the material has excellent arc erosion resistance, especially high-current arc erosion resistance, and has a good application prospect.

Description

Technical Field

[0001] The invention relates to the field of electric contact materials, in particular to a silver tin oxide electric contact material based on an oxide skeleton and a high entropy alloy and a preparation method thereof. Background Art

[0002] Silver tin oxide electrical contact materials are widely used in household appliances, automobiles, new energy, energy storage, 5G, aerospace and other fields.

[0003] Electrical contact materials have the functions of connecting, conducting and cutting off the current. As the oxide content increases, the forming and processing performance of silver tin oxide electrical contact materials will deteriorate sharply, and even become unprocessable; the existing patents related to the preparation of silver tin oxide electrical contact materials are as follows:

[0004] (1) Patent CN115747699A, a method for preparing a high oxide content silver tin oxide sheet contact material (2) Patent CN114093686A, a method and application of improving the plasticity of silver metal oxide electrical contact materials in cold heading riveted electrical contacts

[0005] (3) Patent CN110643847B, Preparation method of silver tin oxide electrical contact material

[0006] (4) Patent CN114694984A, a silver tin oxide smart contact with magnetic field self-regulation function

[0007] The above patent (1) adopts methods such as melting ingots - surface spraying - sintering - extrusion - hot rolling - grinding - finishing rolling to improve the plastic processing ability of extruded plates in the subsequent hot rolling and cold rolling into strips, greatly reducing the side cracking and fracture abnormalities in the hot rolling and cold rolling processes, and improving the material yield.

[0008] Patent (2) uses materials with different oxide contents in the core and surface to form, sinter, extrude and draw, improves the plasticity of low-silver-content silver metal oxide electrical contact materials, solves the problem of cracking at the edge of the working layer of the nail head when cold heading is used to form composite rivet electrical contacts, and obtains a uniform silver layer distribution.

[0009] Patent (3) adopts methods such as powder mixing, wet grinding, drying, molding, and extrusion. The product has a high total oxide content and strong plasticity. It also involves physical processes, and the entire production process is environmentally friendly.

[0010] Patent (4) uses 3D printing, screen printing, template method or injection molding process to prepare a SnO2 skeleton precursor with a predetermined ordered structure. After sintering, liquid Ag is infiltrated into the SnO2 skeleton to form a microscopically three-dimensional ordered Ag phase. This method can greatly improve the arc erosion resistance of the contacts and the breaking capacity of the switch.

[0011] Patents (1)(2)(3) use surface spraying, core and surface different content molding, wet grinding and other methods to produce high oxide content silver electrical contact materials; in patent (1), the matrix is ​​a silver matrix and the silver matrix is ​​not strengthened; in patent (2), only the core layer is a high oxide content material. When the contact burns to the edge, it will lead to a decrease in the anti-welding performance, affecting the number of electrical life tests; in patent (3), the oxide and the matrix are combined in a mechanical manner, which is easy to cause the oxide and the silver matrix to separate during the electrical life test and cannot meet the requirements of long electrical life times; patent (4) uses the method of SnO2 skeleton precursor + liquid Ag infiltration. This method has the problems of low SnO2 skeleton strength, incomplete liquid Ag infiltration, resulting in pores, etc., which affect the number of electrical life times of the contact material. Summary of the invention

[0012] The purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and to provide a silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy and a preparation method thereof. The technical solution adopted by the present invention is as follows:

[0013] In a first aspect, the present invention provides a method for preparing a silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy, comprising the following steps:

[0014] Step 1: Melt the silver ingot, tin ingot and metal additives in a vacuum melting furnace, and obtain the blank of the required profile by 3D printing;

[0015] Step 2: oxidizing the green body of step 1 in an oxygen atmosphere;

[0016] Step 3: at least a portion of the green body oxidized in step 2 is immersed in an acid solution for surface treatment, so that a porous oxide skeleton is obtained on the surface;

[0017] Step 4: subjecting the green body having a porous oxide skeleton on the surface prepared in step 3 to a surface high entropy alloy selective laser melting treatment, so that the high entropy alloy melts and penetrates into the porous oxide skeleton;

[0018] Step 5: Post-treating the material obtained in step 4 to obtain the silver tin oxide electrical contact material.

[0019] High-entropy alloys (HEA for short) are alloys formed by five or more equal or approximately equal amounts of metals.

[0020] Selective laser melting is a major technical approach in additive manufacturing of metal materials. This technology uses laser as the energy source and scans the metal powder bed layer by layer according to the path planned in the 3D CAD slice model. The scanned metal powder is melted and solidified to achieve the effect of metallurgical bonding, and finally the metal parts designed by the model are obtained.

[0021] Preferably, in step 1, the silver content is 65-80 parts by mass, and the tin content is 5-32 parts by mass; the metal additive is two or more of indium, germanium, manganese, cobalt, and titanium, and the metal additive is 2-15 parts by mass.

[0022] Preferably, in step 2, the green body is oxidized in an oxygen atmosphere at an oxygen pressure of 4-10 MPa and a temperature of 550-750° C. for 8-12 hours.

[0023] Preferably, in step 3, the acid solution is a nitric acid aqueous solution, the acid solution concentration is 10-50%, and the soaking time is 5-10 minutes.

[0024] Preferably, in step 4, the high entropy alloy contains silver, nickel, aluminum, titanium and iron; the laser power of the selective laser melting process is 100-800 W, the scanning speed is 200-1000 mm / s, and the scanning spacing is 50-300 μm.

[0025] Preferably, in step 5, the post-treatment comprises: grinding the surface-modified material prepared in step 4 for 5-10 minutes, washing and drying to obtain a finished product.

[0026] In the second aspect, the electrical contact material prepared by the above-mentioned method for preparing silver tin oxide electrical contact material based on oxide skeleton and high entropy alloy also falls within the protection scope of the present invention.

[0027] The beneficial effects of the present invention are as follows: the present invention adopts an in-situ generation method of an oxide skeleton to ensure the strength of the oxide skeleton, and the skeleton is selectively laser melted with a high entropy alloy to modify and strengthen the silver matrix, so that the working layer of the contact prepared using the material has excellent arc erosion resistance, especially resistance to large current arc erosion, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, without paying creative labor, other drawings obtained based on these drawings still belong to the scope of the present invention.

[0029] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings.

[0031] Embodiment 1:

[0032] (1) The silver ingot, tin ingot, indium, and germanium are 65, 32, 2, and 1 parts by mass, respectively. The silver ingot, tin ingot, indium, and germanium are melted in a vacuum melting furnace and printed on a 3D printing device to obtain a rivet-shaped blank, a sheet, a profile, or the like;

[0033] (2) oxidizing the green body prepared in step (1) at a temperature of 750° C. and an oxygen pressure of 4 Pa ​​for 10 h;

[0034] (3) Surface treatment is performed on the oxidized body in step (2): the working layer of the body (in the embodiment of the present invention, it refers to the area with a thickness of 1 mm extending from the working surface of the body to the inside) is immersed in a 10% nitric acid solution for 10 minutes, so that the working layer obtains a porous oxide skeleton.

[0035] (4) The silver, nickel, aluminum, titanium, and iron in the high entropy alloy are 20, 15, 25, 25, and 15 parts by mass, respectively; the high entropy alloy is processed in the working layer by a selective laser melting method with a laser power of 100 W, a scanning speed of 200 mm / s, and a scanning interval of 50 μm.

[0036] (5) Post-processing of the green body: grinding the material obtained in step (4) for 5 minutes, washing and drying to obtain the finished product.

[0037] Embodiment 2:

[0038] (1) The silver ingot, tin ingot, germanium, manganese, cobalt, and titanium are 72.5, 17.5, 4, 2, 3, and 1 parts by mass, respectively. The silver ingot, tin ingot, and additives are melted in a vacuum melting furnace and printed on a 3D printing device to obtain a rivet-shaped, sheet-shaped, profile-shaped blank;

[0039] (2) The green body was oxidized at a temperature of 550°C and an oxygen pressure of 10 Pa for 10 h;

[0040] (3) The green body is subjected to surface treatment, and the working layer of the green body is immersed in a 30% nitric acid solution for 7 minutes. The working layer obtains a porous oxide skeleton.

[0041] (4) The silver, nickel, aluminum, titanium, and iron in the high entropy alloy are 25, 20, 15, 15, and 25 parts by mass, respectively. The high entropy alloy is processed in the working layer by a selective laser melting method with a laser power of 400 W, a scanning speed of 600 mm / s, and a scanning interval of 200 μm.

[0042] (5) The green body is post-processed: grinding for 10 minutes, cleaning and drying to obtain the finished product.

[0043] Embodiment three:

[0044] (1) The weights of silver ingot, tin ingot, indium, germanium, manganese, cobalt, and titanium are 72.5, 17.5, 3, 3, 3, 3, and 3 parts respectively. The silver ingot, tin ingot, and additives are melted in a vacuum melting furnace and printed on a 3D printing device to obtain blanks such as rivet-shaped, sheet-shaped, and profile-shaped materials;

[0045] (2) The green body was oxidized at a temperature of 650°C and an oxygen pressure of 7 Pa for 10 h;

[0046] (3) The green body is subjected to surface treatment, and the working layer of the green body is immersed in a nitric acid solution with a concentration of 50% for 5 minutes. The working layer obtains a porous oxide skeleton.

[0047] (4) The silver, nickel, aluminum, titanium, and iron in the high entropy alloy are 15, 25, 20, 20, and 20 parts by mass, respectively. The high entropy alloy is processed in the working layer by a selective laser melting method with a laser power of 800 W, a scanning speed of 1000 mm / s, and a scanning interval of 300 μm.

[0048] (5) The green body is post-processed: grinding for 10 minutes, cleaning and drying to obtain the finished product.

[0049] Comparative Example 1

[0050] Preparation method of AgSnO2(15):

[0051] (1) Ag powder and SnO2 are 85 and 15 parts by weight respectively, and the above powders are mixed in a high-speed powder mixer for 8 hours, wherein the silver powder particle size is 20-200 μm, and the SnO2 powder particle size is 1-5 μm, to obtain a mixed powder;

[0052] (2) isostatically pressing the mixed powder at a temperature of 300 MPa and a pressure holding period of 120 s to obtain an ingot with a diameter of 80-90 mm;

[0053] (3) The ingot is sintered at a temperature of 800°C for 8 hours;

[0054] (4) Extruding the ingot after heating, the extrusion heating temperature is 860° C., the temperature is kept for 5 hours, and the extrusion pressure is ≤250 MPa to obtain an extruded wire;

[0055] (5) The extruded wire is drawn and annealed to obtain a finished product, which is then made into a rivet and then post-processed to obtain a finished rivet.

[0056] The products of the above-mentioned embodiments 1-3 and comparative example 1 were assembled into relay products, and electrical performance tests were carried out under the conditions of 250V, 50A, lamp load, 1s on and 9s off, and sealing test. The specific results are shown in the following table. It can be seen from the table that the arcing time and electrical life times of the three embodiments are better than those of the comparative example, wherein the arcing time is reduced by about 10ms, the Weibull distribution 95% confidence interval, and the electrical life times are increased by more than 102,000 times.

[0057] Table 1 Comparison of electrical properties of Examples 1-3 and Comparative Example 1

[0058]

[0059] The above disclosure is only a preferred embodiment of the present invention, which is only used to further illustrate the present invention. It certainly cannot be used to limit the scope of rights of the present invention. Therefore, equivalent changes made according to the claims of the present invention are still within the scope covered by the present invention.

Claims

1. A method for preparing a silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy, characterized in that: The following steps are involved: Step 1: Melt the silver ingot, tin ingot and metal additives in a vacuum melting furnace, and obtain the blank of the required profile by 3D printing; Step 2: oxidizing the green body of step 1 in an oxygen atmosphere; Step 3: at least a portion of the green body oxidized in step 2 is immersed in an acid solution for surface treatment, so that a porous oxide skeleton is formed on its surface; Step 4: subjecting the green body having a porous oxide skeleton on the surface prepared in step 3 to a surface high entropy alloy selective laser melting treatment; Step 5: Post-process the blank after the treatment in step 4 to obtain the silver tin oxide electrical contact material.

2. The method for preparing the silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 1, characterized in that: In step 1, the amount of silver is 65-80 parts by weight, and the amount of tin is 5-32 parts by weight.

3. The method for preparing the silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 2, characterized in that: In step 1, the metal additive is two or more of indium, germanium, manganese, cobalt, and titanium, and the metal additive is 2-15 parts by weight.

4. The method for preparing the silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 1, characterized in that: In step 2, the green body is oxidized in an oxygen atmosphere at an oxygen pressure of 4-10 MPa and a temperature of 550-750° C. for 8-12 hours.

5. The method for preparing the silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 1, characterized in that: In step 3, the acid solution is a nitric acid aqueous solution, the acid solution concentration is 10-50%, and the soaking time is 5-10 minutes.

6. The method for preparing the silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 1, characterized in that: In step 4, the high entropy alloy comprises silver, nickel, aluminum, titanium and iron.

7. The method for preparing the silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 1, characterized in that: In step 4, the laser power of the selective laser melting process is 100-800 W, the scanning speed is 200-1000 mm / s, and the scanning interval is 50-300 μm.

8. The method for preparing a silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy according to claim 1, characterized in that: In step 5, the post-processing includes: grinding for 5-10 minutes, washing and drying to obtain the finished product.

9. The silver tin oxide electrical contact material prepared by the method for preparing a silver tin oxide electrical contact material based on an oxide skeleton and a high entropy alloy as described in any one of claims 1 to 8.

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