Silver-copper oxide contact material resistant to soldering and method for producing the same

Abstract

This invention discloses a silver-copper oxide contact material with anti-fusion welding properties and its preparation method. The material comprises, by weight, 80-95 parts silver powder, 5-15 parts copper oxide powder, 0.1-3 parts anti-fusion welding additive, and 0.05-0.5 parts wetting modifier; wherein the additive is niobium-coated yttrium oxide-stabilized zirconia microspheres loaded with bismuth oxide, and the wetting modifier is lanthanum hexaboride nanoparticles modified with a silane coupling agent. This invention, through the synergistic effect of a core-shell microcapsule controlled-release structure and interfacial chemical modification, inhibits the premature volatilization of low-melting-point components, improves nanoparticle dispersion and interfacial bonding, reduces arc voltage, and accelerates arc extinguishing, significantly improving the anti-fusion welding performance and arc burn-off resistance of the contact material.

Description

Technical Field

[0001] This invention relates to the field of electrical contact materials technology, and more specifically, to a silver-copper oxide contact material resistant to welding and its preparation method. Background Technology

[0002] Silver oxide copper contact materials are widely used in various low-voltage electrical applications due to their excellent electrical conductivity, thermal conductivity, and environmental friendliness. To further improve the overall electrical performance and service life of the contact materials, industrial manufacturing typically involves adding a certain proportion of anti-welding additives and nano-modifiers to the matrix material. However, existing silver oxide copper contact materials still face many technical bottlenecks in practical applications.

[0003] First, while traditional anti-welding agents (such as bismuth oxide) can prevent contact welding by reducing the surface tension of the molten pool, their inherent melting and boiling points are low. Under the high temperature of the electric arc generated during contact breaking, these low-melting-point substances easily vaporize rapidly and spatter, leading to excessively rapid wear of the contact material. Adding high-melting-point skeleton materials simply to improve high-temperature resistance would significantly increase the material's contact resistance, failing to achieve effective anti-welding. Existing technologies have consistently struggled to resolve the contradiction between the easy vaporization and loss of anti-welding additives under electric arc conditions and their poor resistance to arc burn-off.

[0004] Secondly, to improve the microstructure of materials, current techniques often involve directly adding inorganic nanoparticles into the silver matrix. However, due to the extremely large specific surface area and surface energy of inorganic nanoparticles, they are prone to agglomeration in the matrix. Simultaneously, common oxides or borides exhibit poor interfacial wettability and very weak chemical bonding with metallic silver. This poor interfacial compatibility leads to defects such as micropores and microcracks within the contact material, not only reducing the material's density and mechanical strength but also severely degrading its overall electrical conductivity.

[0005] Furthermore, existing contact materials often face the problem of arc instability during prolonged and high-frequency opening and closing operations. When the arc burning time is too long and the arc energy is excessively concentrated, it will cause extremely strong thermal shock to the contact surface, leading to severe local burn-off and material transfer, which will significantly reduce the safety and reliability of the switching device.

[0006] In summary, overcoming the defects of premature volatilization and spatter of traditional anti-welding components, solving the problems of agglomeration and poor interfacial bonding of inorganic nano-additives in metal matrices, and effectively stabilizing and accelerating arc extinction to reduce thermal shock, thereby balancing and improving the anti-welding properties and arc burn-off life of contact materials, are the core technical challenges that urgently need to be solved in this field. Summary of the Invention

[0007] To address the technical problems in existing technologies, such as the easy vaporization and loss of anti-welding additives under high-temperature electric arcs, the easy agglomeration of nano-modifiers and poor interfacial bonding, and insufficient resistance to electric arc burn-off, the present invention aims to provide an anti-welding silver oxide copper contact material and its preparation method. The aim is to stabilize and accelerate the extinction of the electric arc by constructing a microcapsule controlled-release structure and interfacial chemical modification, thereby comprehensively balancing and significantly improving the anti-welding properties and service life of the contact material.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] 1. A silver-copper oxide contact material resistant to fusion welding, characterized in that it comprises the following raw material components by weight:

[0010] 80-95 parts silver powder;

[0011] 5-15 parts of copper oxide powder;

[0012] Anti-welding additive 0.1-3 parts;

[0013] 0.05-0.5 parts of wetting modifier;

[0014] The anti-welding additive is yttrium-stabilized zirconia microspheres coated with niobium-loaded bismuth oxide. Its structure includes a yttrium-stabilized zirconia framework, a bismuth oxide core filled in the framework, and a dense niobium shell covering the outer surface of the framework.

[0015] The wetting modifier is lanthanum hexaboride nanoparticles with a surface modified by a silane coupling agent.

[0016] Furthermore, the silver powder is selected from one or more of high-purity silver powder, ultrafine silver powder, and nano silver powder.

[0017] Furthermore, the copper oxide powder is selected from one or more of micron-sized copper oxide powder, nano-sized copper oxide powder, and spherical copper oxide powder.

[0018] Furthermore, in the anti-fusion welding additive, the dense niobium shell is formed by cold welding niobium powder onto the outer surface of the skeleton using a mechanical fusion method.

[0019] Furthermore, the silane coupling agent is selected from one or more of silane coupling agents KH-550, KH-560, and KH-570.

[0020] A method for preparing a silver-copper oxide contact material resistant to fusion welding includes the following steps:

[0021] The first step is the preparation of the anti-welding additive: Yttrium-stabilized zirconia microspheres are immersed in a dilute bismuth nitrate solution. Under vacuum conditions, the pressure is maintained to allow the solution to fully enter the microsphere channels. After washing and calcination, the bismuth nitrate inside the pores is pyrolyzed in situ to bismuth oxide, resulting in a bismuth oxide-loaded framework powder. The framework powder is mixed with niobium powder and subjected to high-energy ball milling. Mechanochemical action is used to cold-weld the niobium powder onto the surface of the framework powder to form a dense shell, thus obtaining the anti-welding additive.

[0022] The second step is the treatment of the wetting modifier: Lanthanum hexaboride nanoparticles are ultrasonically dispersed in anhydrous ethanol, a silane coupling agent is added and the mixture is stirred and refluxed in a water bath, and then centrifuged and vacuum dried to obtain the surface-modified wetting modifier.

[0023] The third step is raw material mixing: weigh silver powder, copper oxide powder, anti-welding additives prepared in the first step and wetting modifiers prepared in the second step according to the mass ratio, add them to a three-dimensional mixer and mix them in anhydrous ethanol medium. After vacuum drying, a composite mixed powder is obtained.

[0024] The fourth step is pressing and sintering: the composite powder is isostatically pressed into a green body, and then sintered under a nitrogen protective atmosphere to obtain a sintered green body.

[0025] Step 5, re-pressing and post-processing: The sintered blank is re-pressed, and then hot-extruded and machined to obtain the anti-welding silver-copper oxide contact material.

[0026] Further, in the first step, the concentration of the bismuth nitrate dilute nitric acid solution is 0.5-1.0 mol / L; the vacuum condition is 0.05-0.1 MPa, and the holding time is 24 h; the calcination is carried out by heating to 600-650℃ at a heating rate of 5℃ / min and holding for 3-5 h; the average particle size of the niobium powder is 50-100 nm, and the mass ratio of the skeleton powder to the niobium powder is 1:(0.1-0.2); the high-energy ball milling is carried out under an argon protective atmosphere at a rotation speed of 1500-2000 r / min for 30-60 min.

[0027] Furthermore, in the second step, the amount of the silane coupling agent added accounts for 13% of the mass of the lanthanum hexaboride; the temperature of the water bath stirring reflux is 60°C, and the time is 2 hours.

[0028] Furthermore, in the third step, the mixing process takes 2-4 hours.

[0029] Furthermore, in the fourth step, the isostatic pressing pressure is 300-500 MPa, the sintering temperature is 800-850℃, and the holding time is 2-4 hours.

[0030] Furthermore, in the fifth step, the pressure of the re-pressure treatment is 600-800 MPa.

[0031] A silver-copper oxide contact material resistant to welding relates to the manufacture of a novel precious metal material for electrical contacts.

[0032] A type of silver-copper oxide contact material resistant to fusion welding can be used in intelligent welding systems, intelligent heat treatment production lines, laser rapid prototyping equipment, and other unlisted general equipment manufacturing industries.

[0033] This invention relates to an anti-welding additive consisting of a yttrium-stabilized zirconia framework, a bismuth oxide core, and a dense niobium shell. The core-shell structure enables controlled-release microcapsule functionality. The niobium shell acts as a physical barrier, providing thermal shielding and effectively preventing premature volatilization of the low-melting-point bismuth oxide under the influence of small electric arcs during routine operations. Only under extreme conditions of high-current surges that could trigger welding will the outer niobium shell rupture and release bismuth oxide, reducing the surface tension of the molten pool and thus preventing welding. Simultaneously, the high-melting-point yttrium-stabilized zirconia framework provides mechanical support at high temperatures, delaying heat loss. Furthermore, lanthanum hexaboride nanoparticles modified with a silane coupling agent act as a wetting modifier. This surface chemical modification resolves the agglomeration of inorganic nanoparticles in the metal matrix and establishes a chemical bridge between the inorganic borides and the silver matrix, improving the wettability and bonding strength at the interface, suppressing internal pores and microcracks, and enhancing the density and conductivity of the matrix. Uniformly dispersed lanthanum hexaboride possesses extremely low electron work function, which can reduce arc voltage and stabilize and accelerate the arc extinguishing process, thereby reducing the continuous thermal shock of the arc to the contact surface from the source. The perfect synergy between the added substances in microstructure and electrical mechanism ensures that the arc thermal shock is suppressed to a minimum, while also endowing the contacts with the ability to dynamically self-repair under extreme arc conditions and to target and control the release of anti-welding materials. This comprehensively improves the structural uniformity, arc wear resistance life, and overall anti-welding performance of the contact material.

[0034] Compared with the prior art, the beneficial effects of the present invention are:

[0035] 1. This invention introduces yttrium-stabilized zirconia microspheres coated with niobium-loaded bismuth oxide as an anti-welding additive, constructing a core-shell microcapsule structure consisting of a framework, a low-melting-point inner core, and a high-melting-point dense outer shell. The dense niobium shell acts as a physical barrier, providing excellent thermal shielding and controlled release, preventing premature volatilization and loss of the internal bismuth oxide under the influence of small electric arcs generated during daily operation. In extreme conditions such as high-current arcs that easily trigger welding, the outer niobium layer ruptures and releases the internal bismuth oxide, thereby rapidly reducing the surface tension of the molten pool and precisely exerting its anti-welding effect. Simultaneously, the high-melting-point yttrium-stabilized zirconia framework provides robust mechanical support for the material at high temperatures, preventing rapid wear of the contact material and significantly extending the contact's service life.

[0036] 2. This invention uses lanthanum hexaboride nanoparticles modified with a silane coupling agent as a wetting modifier. The surface modification with the silane coupling agent not only achieves highly uniform dispersion of the nanoparticles in the silver matrix, fundamentally preventing the aggregation of inorganic nanoparticles, but also establishes a stable chemical bridge between the inorganic boride nanoparticles and the metallic silver matrix. This significantly improves the wettability and bonding force at the interface between the inorganic and metallic phases, eliminates defects such as micropores and microcracks that are prone to occur inside the contact material, thereby comprehensively improving the overall density, mechanical strength, and electrical conductivity of the composite material.

[0037] 3. The uniformly dispersed lanthanum hexaboride in the wetting modifier possesses extremely low electron work function, which significantly reduces arc voltage, stabilizes and greatly accelerates the arc extinguishing process, thereby reducing the continuous thermal shock of the arc to the contact surface from the source. The arc suppression characteristics and the microencapsulated dynamic controlled release mechanism of the anti-welding additive work synergistically, ensuring that the contacts have self-protection and anti-welding capabilities under extreme arc conditions, while also reducing the overall arc burn-off rate of the material. The synergy of these two factors not only minimizes arc thermal shock but also comprehensively improves the structural uniformity and electrical wear resistance of the contact material, greatly enhancing the long-term safety and reliability of low-voltage switching devices. Attached Figure Description

[0038] Figure 1 This is a comparison chart of Vickers hardness and electrical conductivity between embodiments and comparative examples of the present invention. Detailed Implementation

[0039] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] Example 1

[0041] Preparation of a silver-copper oxide contact material resistant to fusion welding:

[0042] 1. Raw material components by weight:

[0043] 90 parts of silver powder, selected from nano silver powder with an average particle size of 50nm and a purity of ≥99.9%;

[0044] Nine parts of copper oxide powder, selected as nano-sized copper oxide powder with an average particle size of 200nm and a purity of ≥99.5%;

[0045] 0.5 parts of anti-fusion welding additive;

[0046] 0.2 parts of wetting modifier.

[0047] 2. Preparation method:

[0048] Step 1, Preparation of anti-welding additive:

[0049] Yttrium oxide-stabilized zirconia microspheres with an average particle size of 2 μm and a Y₂O₃ content of 8 mol% were impregnated in a 0.8 mol / L bismuth nitrate dilute nitric acid solution, wherein the concentration of dilute nitric acid was 0.5 mol / L. The mixture was placed in a vacuum impregnation tank, and the vacuum was evacuated to a degree of 0.08 MPa and maintained at that pressure for 24 h to allow the bismuth nitrate solution to fully enter the pores of the yttrium oxide-stabilized zirconia microspheres. Subsequently, the microspheres were washed three times with deionized water and dried in a vacuum drying oven at 80 °C for 12 h. Then, the microspheres were heated to 620 °C at a heating rate of 5 °C / min and calcined for 4 h to allow the bismuth nitrate in the pores to be pyrolyzed in situ into bismuth oxide, thus obtaining a bismuth oxide-loaded framework powder.

[0050] The above-mentioned framework powder and niobium powder with an average particle size of 80 nm were placed in a high-energy ball mill at a mass ratio of 1:0.15. Under an argon protective atmosphere, the mixture was ball-milled at a speed of 1800 r / min for 45 min to obtain niobium-coated yttrium-stabilized zirconia microspheres loaded with bismuth oxide. The structure includes a yttrium-stabilized zirconia framework, a bismuth oxide core filled in the framework, and a dense niobium shell covering the outer surface of the framework.

[0051] The second step is the treatment of the wetting modifier:

[0052] Lanthanum hexaboride nanoparticles were added to anhydrous ethanol and ultrasonically dispersed for 30 min to prepare a suspension with a mass concentration of 5%. Silane coupling agent KH-550, accounting for 13% of the mass of lanthanum hexaboride, was added to the suspension, and the mixture was stirred and refluxed in a 60°C water bath for 2 h. After the reaction, the mixture was centrifuged, and the resulting solid was dried in a vacuum drying oven at 80°C for 12 h to obtain lanthanum hexaboride nanoparticles modified with the silane coupling agent, which is the wetting modifier.

[0053] Step 3: Mixing the ingredients:

[0054] Weigh out the silver powder, copper oxide powder, the anti-welding additive prepared in the first step, and the wetting modifier prepared in the second step according to the above-mentioned mass proportions, add them to the three-dimensional mixer, add anhydrous ethanol as a medium, and add the amount of anhydrous ethanol just enough to immerse the powder. Mix and treat for 3 hours at a speed of 50 r / min. After mixing, place the resulting slurry in an 80℃ vacuum drying oven and dry it to constant weight to obtain a composite mixed powder.

[0055] Step 4: Pressing and sintering to form the shape:

[0056] The above-mentioned composite powder was loaded into a rubber mold and isostatically pressed under a pressure of 400 MPa to obtain a green blank. The green blank was placed in a sintering furnace and heated to 820°C at a heating rate of 5°C / min under a nitrogen protective atmosphere. It was then held at that temperature for 3 hours to obtain a sintered green body.

[0057] Step 5, Recompression and Post-processing:

[0058] The sintered preform was subjected to a re-pressing treatment at 700 MPa, followed by hot extrusion molding at 800°C with an extrusion ratio of 10:1. Finally, it was machined to the designed dimensions to obtain the finished silver oxide copper contact material that resists fusion welding.

[0059] Example 2

[0060] The preparation of a silver-copper oxide contact material with anti-welding properties is carried out according to the preparation method of Example 1, except that the mass parts of silver powder, copper oxide powder, anti-welding additive and wetting modifier are replaced with 80 parts, 15 parts, 3 parts and 0.5 parts respectively, and the rest are the same as in Example 1.

[0061] Example 3

[0062] The preparation of a silver oxide copper contact material resistant to fusion welding is carried out by referring to the preparation method of Example 1, except that the silane coupling agent KH-550 is replaced with the silane coupling agent KH-560, and the rest is the same as in Example 1.

[0063] Example 4

[0064] The preparation of a silver oxide copper contact material resistant to fusion welding is carried out according to the preparation method of Example 1, except that the 0.8 mol / L bismuth nitrate dilute nitric acid solution is replaced with 0.5 mol / L bismuth nitrate dilute nitric acid solution, and the calcination temperature of the in-situ pyrolysis of bismuth nitrate in the hole is changed to 600°C, while the rest is the same as in Example 1.

[0065] Comparative Example 1

[0066] The preparation of a silver-copper oxide contact material resistant to welding is carried out by referring to the preparation method of Example 1, except that the anti-welding additive is replaced with yttrium-stabilized zirconia microspheres loaded with bismuth oxide without niobium coating (i.e., without the niobium powder coating step), and the rest is the same as in Example 1.

[0067] Comparative Example 2

[0068] The preparation of a silver-copper oxide contact material resistant to welding is carried out according to the preparation method of Example 1, except that the anti-welding additive is replaced with yttrium-stabilized zirconia microspheres that are not internally loaded with bismuth oxide and have niobium metal coating on the surface (i.e., they are not soaked in bismuth nitrate dilute nitric acid solution), and the rest is the same as in Example 1.

[0069] Comparative Example 3

[0070] The preparation of a silver-copper oxide contact material resistant to fusion welding is carried out according to the preparation method of Example 1, except that the bismuth nitrate in the 0.8 mol / L bismuth nitrate dilute nitric acid solution is replaced with an equimolar amount of zinc nitrate (i.e., the zinc oxide core is ultimately replaced with the bismuth oxide core), and the rest is the same as in Example 1.

[0071] Comparative Example 4

[0072] The preparation of a silver oxide copper contact material resistant to fusion welding is carried out by referring to the preparation method of Example 1, except that the niobium powder is replaced with copper powder of equal particle size and mass (i.e., a dense copper shell is used instead of a dense niobium shell), and the rest is the same as in Example 1.

[0073] Comparative Example 5

[0074] The preparation of a silver oxide copper contact material resistant to welding is the same as in Example 1, except that the anti-welding additive is not added.

[0075] Comparative Example 6

[0076] The preparation of a silver oxide copper contact material resistant to fusion welding is carried out according to the preparation method of Example 1, except that the wetting modifier is not added, and the rest is the same as in Example 1.

[0077] Comparative Example 7

[0078] The preparation of a silver oxide copper contact material resistant to fusion welding is carried out according to the preparation method of Example 1, except that the wetting modifier is replaced with unmodified graphite powder, and the rest is the same as in Example 1.

[0079] Performance testing:

[0080] 1. Vickers Hardness Test: After the finished contact material is inlaid, ground, and polished, its hardness is measured using a Vickers hardness tester. The test conditions are: a load of 1 kgf, a holding time of 15 s, and 5 test points are randomly selected on the cross-section of the sample. The center-to-center distance between each indentation is not less than 3 times the length of the diagonal of the indentation. The data are shown in Table 1.

[0081] 2. Conductivity Test: The conductivity of the finished contact material was determined using the four-probe method. The sample to be tested was processed into a rectangular block with dimensions of 10mm × 10mm × 2mm. After surface cleaning, it was placed on a four-probe tester with a probe spacing of 1mm and a test current of 1A. Measurements were taken three times each along the length and width of the sample at room temperature. The arithmetic mean of the six measurements was taken as the conductivity of the sample. The data are shown in Table 1.

[0082] 3. Anti-welding performance test: The welding force of the contact material was tested using a contact material welding force testing device. The finished contact material was processed into cylindrical contacts with a diameter of 6 mm and a height of 3 mm, and paired and installed in the testing device. Under the conditions of constant contact pressure of 5 N and switching frequency of 1 Hz, a DC resistive load current of 30 A was applied to conduct a switching cycle test. The welding force at each disconnection was recorded. The anti-welding performance was evaluated by the number of welding failures (welding force exceeding the preset threshold of 50 N) in 10,000 consecutive switching cycles. The data are shown in Table 1.

[0083] 4. Arc burn resistance test: The contact life test system was used for evaluation. The finished contact material was processed into cylindrical contacts with a diameter of 6 mm and a height of 3 mm, which were then paired with mating contacts to form contact pairs and installed in the test system. The test conditions were: AC load 220V / 10A, power factor 0.8, switching frequency 6 times / min, duty cycle 50%. Continuous switching operations were performed under rated load, and the contact resistance of the contact pair and the mass loss of individual contacts were measured every 10,000 cycles. When the contact resistance increased by more than 50% from the initial value or the contact mass loss exceeded 10% of the initial mass, it was judged as a failure. The total number of switching operations was recorded as the arc burn life, and the data are shown in Table 1.

[0084] Table 1

[0085] Vickers hardness (HV) Electrical conductivity (MS / m) Number of fusion welding failures (times) Arc burn-off life (times) Example 1 92.5 49.8 0 105,000 Example 2 91 50.2 1 98,000 Example 3 89.5 48.9 2 96,500 Example 4 90.8 51 1 102,000 Comparative Example 1 88.2 48.5 18 65,000 Comparative Example 2 94 48.8 38 72,000 Comparative Example 3 89 47.5 12 80,000 Comparative Example 4 86.5 48.2 15 75,000 Comparative Example 5 78 53.5 55 40,000 Comparative Example 6 65.5 38.6 25 48,000 Comparative Example 7 61 35.2 20 42,000

[0086] The overall performance of the example group was significantly better than that of all comparative groups, demonstrating a good synergistic effect among the components and core-shell structure of the present invention. Within the example group, the baseline formulation exhibited the most balanced overall performance. Increasing the amount of additives and modifiers, changing the type of coupling agent, or reducing the precursor concentration and calcination temperature caused slight fluctuations in some properties, but the overall performance remained superior. The absence of a dense niobium shell or bismuth oxide core led to a sharp deterioration in anti-fusion welding performance and arc burn-off resistance, and simply retaining the high-melting-point skeleton could not solve the welding problem; replacing the niobium shell and bismuth oxide core with other metals or inactive materials could not achieve the same effect. Omitting anti-fusion welding additives caused the contacts to lose their core anti-fusion welding capability and significantly shortened the arc burn-off resistance; while omitting or replacing wetting modifiers caused the material density and interfacial bonding to collapse, resulting in a sharp drop in hardness and conductivity, while anti-fusion welding and arc burn-off resistance declined significantly at the same time. The integrity of the core-shell microcapsule structure, the precise controlled release of the low-melting-point core, the mechanical support of the high-melting-point skeleton, and the surface-modified nano-wetting modifier are all indispensable. Together, they constitute the comprehensive balance and significant improvement of the contact material of this invention in terms of mechanical properties, electrical conductivity, anti-welding properties, and arc burn-off life.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A silver-copper oxide contact material resistant to fusion welding, characterized in that, By weight, it includes the following raw material components: 80-95 parts silver powder; 5-15 parts of copper oxide powder; Anti-welding additive 0.1-3 parts; 0.05-0.5 parts of wetting modifier; The anti-welding additive is yttrium-stabilized zirconia microspheres coated with niobium oxide and loaded with bismuth oxide. Its structure includes a yttrium-stabilized zirconia framework, a bismuth oxide core filled in the framework, and a dense niobium shell covering the outer surface of the framework. The wetting modifier is lanthanum hexaboride nanoparticles with a surface modified by a silane coupling agent.

2. The anti-welding silver-copper oxide contact material according to claim 1, characterized in that, The silver powder is selected from one or more of high-purity silver powder, ultrafine silver powder, and nano silver powder.

3. The anti-welding silver-copper oxide contact material according to claim 1, characterized in that, The copper oxide powder is selected from one or more of micron-sized copper oxide powder, nano-sized copper oxide powder, and spherical copper oxide powder.

4. The anti-welding silver-copper oxide contact material according to claim 1, characterized in that, In the anti-fusion welding additive, the dense niobium shell is formed by cold welding niobium powder onto the outer surface of the skeleton using a mechanical fusion method.

5. The anti-welding silver-copper oxide contact material according to claim 1, characterized in that, The silane coupling agent is selected from one or more of silane coupling agents KH-550, KH-560, and KH-570.

6. A method for preparing a silver-copper oxide contact material resistant to fusion welding as described in any one of claims 1-5, characterized in that, Includes the following steps: The first step is the preparation of the anti-welding additive: Yttrium-stabilized zirconia microspheres are immersed in a dilute bismuth nitrate solution. Under vacuum conditions, the pressure is maintained to allow the solution to fully enter the microsphere channels. After washing and calcination, the bismuth nitrate inside the pores is pyrolyzed in situ to bismuth oxide, resulting in a bismuth oxide-loaded framework powder. The framework powder is mixed with niobium powder and subjected to high-energy ball milling. Mechanochemical action is used to cold-weld the niobium powder onto the surface of the framework powder to form a dense shell, thus obtaining the anti-welding additive. The second step is the treatment of the wetting modifier: Lanthanum hexaboride nanoparticles are ultrasonically dispersed in anhydrous ethanol, a silane coupling agent is added and the mixture is stirred and refluxed in a water bath, and then centrifuged and vacuum dried to obtain the surface-modified wetting modifier. The third step is raw material mixing: weigh silver powder, copper oxide powder, anti-welding additives prepared in the first step and wetting modifiers prepared in the second step according to the mass ratio, add them to the three-dimensional mixer and mix them in anhydrous ethanol medium. After vacuum drying, a composite mixed powder is obtained. The fourth step is pressing and sintering: the composite powder is isostatically pressed into a green body, and then sintered under a nitrogen protective atmosphere to obtain a sintered green body. Step 5, re-pressing and post-processing: The sintered blank is re-pressed, and then hot-extruded and machined to obtain the anti-welding silver-copper oxide contact material.

7. The method for preparing a silver-copper oxide contact material resistant to fusion welding according to claim 6, characterized in that, In the first step, the concentration of the bismuth nitrate dilute nitric acid solution is 0.5-1.0 mol / L; the vacuum condition is 0.05-0.1 MPa, and the holding time is 24 h; the calcination is carried out by heating to 600-650℃ at a heating rate of 5℃ / min and holding for 3-5 h; the average particle size of the niobium powder is 50-100 nm, and the mass ratio of the skeleton powder to the niobium powder is 1:(0.1-0.2); the high-energy ball milling is carried out under an argon protective atmosphere at a rotation speed of 1500-2000 r / min for 30-60 min.

8. The method for preparing a silver-copper oxide contact material resistant to fusion welding according to claim 6, characterized in that, In the second step, the amount of the silane coupling agent added accounts for 13% of the mass of the lanthanum hexaboride; the temperature of the water bath stirring and reflux is 60°C, and the time is 2 hours.

9. The method for preparing a silver-copper oxide contact material resistant to fusion welding according to claim 6, characterized in that, In the third step, the mixing process takes 2-4 hours. In the fourth step, the isostatic pressing pressure is 300-500 MPa, the sintering temperature is 800-850℃, and the holding time is 2-4 hours.

10. The method for preparing a silver-copper oxide contact material resistant to fusion welding according to claim 6, characterized in that, In the fifth step, the pressure of the re-pressure treatment is 600-800 MPa.

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