Silver tin oxide electric contact material based on doped CsPbBr quantum dots and preparation method of silver tin oxide electric contact material

Abstract

The invention belongs to the field of electric contact materials, and particularly relates to a silver tin oxide electric contact material based on doped CsPbBr3 quantum dots and a preparation method of the silver tin oxide electric contact material based on the doped CsPbBr3 quantum dots. By adopting a mode of doping the CsPbBr3 quantum dots, the quantum dots with the surfaces modified with oleic acid / oleylamine are uniformly dispersed between Ag and SnO2, and a special energy band structure is formed by utilizing a quantum confinement effect; and the conductivity of the silver tin oxide composite material is improved. And the CsPbBr3 quantum dots have a unique arc extinguishing mechanism: Br <-> ions are easy to lose and can capture high-energy free electrons generated by an electric arc and reduce energy accumulation, and the quantum dots are uniformly dispersed in the material, so that the propagation path of the electric arc is favorably disrupted, and the arc resistance is improved. According to the mixed powder prepared through atomization powder preparation and special powder oxidation, the oxidation uniformity is guaranteed, meanwhile, the proportion can be adjusted at will according to needs, the problem of oxidation difficulty is avoided, and the prepared material is better in plasticity, low in hardness and easy to machine.

Description

Technical Field

[0001] The present invention belongs to the field of electrical contact materials, and in particular relates to a silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots and a preparation method thereof. Background Art

[0002] As the most widely used electrical contact material, the AgMeO series is undergoing significant technological innovation. With the global rise in environmental awareness, the more eco-friendly silver tin oxide material has become a key development direction in the industry. This new environmentally friendly electrical contact material, with its excellent performance, has been successfully applied in high-end manufacturing fields such as smart home devices, new energy vehicles, renewable energy systems, 5G communications equipment, and aerospace, strongly supporting the green transformation and upgrading of modern industry.

[0003] However, traditional AgSnO2 materials suffer from unstable contact resistance and low carrier mobility. Existing technologies often improve performance by doping with metal oxides (such as WO3 and CuO) or carbon materials, but these methods have limited control over carrier behavior and can easily lead to reduced interfacial compatibility.

[0004] Through relevant literature, the relevant patents retrieved are as follows:

[0005] (1) Patent CN102268583A, a method for preparing a silver tin oxide electrical contact material, proposes a process for preparing a silver tin oxide electrical contact material, specifically using medium frequency smelting technology to melt tin and multi-metal additives in a precise ratio to form a uniform alloy, and then atomizing to obtain tin-based alloy powder. Subsequently, the alloy powder is converted into a tin oxide composite powder through a controlled oxidation process, and after mechanical mixing with high-purity silver powder, cold isostatic pressing, gradient sintering and hot extrusion are carried out in sequence to finally produce high-performance silver tin oxide wire. This process significantly improves the homogeneity and physical stability of the material by optimizing the distribution of alloy elements and the composite structure of oxides;

[0006] (2) Patent CN105702503A, a method for preparing silver oxide, tin oxide and indium oxide contact materials, innovatively introduces a tin-indium alloy matrix and a multiphase sintering aid, which effectively improves the sintering kinetics of the material through synergistic effects, allowing the silver matrix to form a three-dimensional interconnected conductive network, while ensuring that the material density reaches more than 98.5%, while reducing the contact resistance to below 1.5 μΩ·cm;

[0007] (3) Patent CN105200262B, a method for preparing a silver-based sheet electrical contact material with a high tin oxide content, develops a novel preparation route combining bulk oxidation with thermomechanical processing. This structural design improves the material's wear resistance while maintaining excellent electrical conductivity;

[0008] (4) Patent CN107598176B, a process for preparing silver metal oxide electrical contact materials, utilizes a breakthrough integrated alloy melt atomization-in-situ oxidation technology to directly prepare alloy microspheres with a complete surface oxide layer by precisely controlling the atomization parameters. This process eliminates the traditional powder oxidation step, improving material utilization and shortening the production cycle. It also achieves a gradient distribution of the oxide phase within the silver matrix, extending the material's electrical contact life.

[0009] Among the above-mentioned existing documents, patents (1), (2), and (3) use alloy atomization powdering, tin-indium alloy doping, crushing and pressing to form ingots and other methods to prepare high-oxide content silver electrical contact materials. However, these materials suffer from poor burnout performance during actual application and are increasingly unable to meet the current trend of high-performance development. Although patent (4) improves production efficiency, its "core-shell" structure micro-control has essential defects: during the gradient oxidation process, the atomized alloy microspheres are limited by the oxygen diffusion kinetics mechanism, and an oxide-poor core region with a diameter of 5-8 μm is formed inside the spheres with a diameter exceeding 20 μm, resulting in a 12-15% decrease in the proportion of the effective conductive phase.

[0010] In recent years, perovskite quantum dots (such as CsPbBr3) have attracted much attention in the field of optoelectronic devices due to their high carrier mobility, tunable band gap, and quantum confinement effect. However, their application in metal-based composites has not been reported. Therefore, it is urgent to develop a new doping strategy to break through the performance bottleneck of AgSnO2 materials. Summary of the Invention

[0011] 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 doped CsPbBr3 quantum dots and a preparation method thereof.

[0012] The technical solution adopted by the present invention is as follows: a method for preparing a silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots, comprising the following steps:

[0013] Step (1): dissolving Cs2CO3 and PbBr2 in a mixed solvent of octadecene and oleic acid, heating the mixture in an oil bath under nitrogen protection, cooling the mixture and centrifuging to obtain quantum dots;

[0014] Step (2): adding the quantum dots prepared in step (1) and SnCl4·5H2O to ethanol, mixing, ultrasonically dispersing, and spray drying to obtain a SnO2 / CsPbBr3 precursor;

[0015] Step (3): The silver ingot, tin ingot and additives are melted, atomized, dried and oxidized to obtain a mixed metal powder;

[0016] Step (4): ball-milling the SnO2 / CsPbBr3 precursor of step (2) and the mixed metal powder prepared in step (3), isostatically pressing the mixture, and then obtaining an ingot by spark plasma sintering.

[0017] Step (5): hot-extrude the ingot prepared in step (4) into a wire, and finally draw it into a finished wire of desired specifications.

[0018] Further configuration is that, in step (1), the reaction temperature is 150-200° C., and the reaction time is 2-4 h.

[0019] It is further configured that, in step (2), the ultrasonic dispersion temperature is 30-60° C. and the time is 15-60 min.

[0020] It is further arranged that, in step (2), the spray drying pressure is 20-50 MPa.

[0021] It is further configured that in step (3), the composition and content of the mixed metal powder are: the mass percentage of silver is 85% to 90%, the mass percentage of tin is 5% to 15%, and the remainder is additives, and the additives are two or more of indium, germanium, manganese, cobalt, and titanium.

[0022] Further settings are that in step (4), the ball milling mixing parameters are a ball-to-material ratio of 5:1, a rotation speed of 300 rpm, a time of 2 h, an isostatic pressing pressure of 200-300 MPa, a spark plasma sintering pressure of 30-50 MPa, a temperature of 400-600°C, a heat preservation time of 1-2 h, and a pulse current on-off ratio of 10:1.

[0023] It is further provided that, in the ingot prepared in step (4), the mass percentage of CsPbBr3 quantum dots is 0.5% to 5%.

[0024] It is further configured that the heating parameters in step (5) are: temperature 800°C to 880°C, insulation time 1 to 3 hours, and then hot extrusion into extruded wires with a diameter of φ5mm to φ8mm.

[0025] The silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots is prepared by the method for preparing the silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots as described above.

[0026] The beneficial effects of the present invention are as follows: The present invention innovatively adopts the method of doping CsPbBr3 quantum dots so that the surface-modified oleic acid / oleylamine quantum dots are evenly dispersed between Ag and SnO2, and uses the quantum confinement effect to form a special band structure, so that the conductivity of the silver tin oxide composite material is improved. At the same time, the present invention finds that CsPbBr3 quantum dots have a unique arc extinguishing mechanism: Br- ions are easily missing, which can capture high-energy free electrons generated by the arc, reduce energy accumulation, and because the quantum dots are evenly dispersed in the material, it is beneficial to disrupt the propagation path of the arc and improve the arc resistance. Furthermore, the mixed powder prepared by atomization powder making and special powder oxidation adopted by the present invention can be arbitrarily adjusted in proportion as needed while ensuring oxidation uniformity, and there will be no problem of oxidation difficulty. The obtained material has better plasticity, low hardness, and is easy to process. DETAILED DESCRIPTION

[0027] The present invention is specifically described below through examples, which are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Technical engineers in this field can make some non-essential improvements and adjustments to the present invention based on the contents of the above invention.

[0028] Example 1:

[0029] This embodiment is carried out according to the following steps:

[0030] (1) Cs2CO3 and PbBr2 were dissolved in a mixed solvent of octadecene and oleic acid, heated in an oil bath under nitrogen protection, cooled and centrifuged to obtain quantum dots with surface modification of oleic acid / oleylamine, wherein the reaction temperature was 150°C and the reaction time was 2 h;

[0031] (2) The quantum dots prepared in step (1) were mixed with SnCl4·5H2O in a mass ratio of 1:10 and added to ethanol, and ultrasonically dispersed and spray-dried to obtain a SnO2 / CsPbBr3 precursor, wherein the ultrasonic dispersion temperature was 35°C, the time was 30 min, and the spray drying pressure was 35 MPa;

[0032] (3) 30 kg of silver ingots, tin ingots, indium, and germanium were melted and atomized in a mass ratio of 85:12:2:1, dried, oxidized with special powders, and sieved to obtain a mixed metal powder, wherein the special powder oxidation temperature was 700°C, the oxidation pressure was 0.6-1.5 MPa, and the oxidation time was 54 h;

[0033] (4) The SnO2 / CsPbBr3 precursor of step (2) and the mixed metal powder prepared in step (3) were ball-milled in a mass ratio of 1:6, isostatically pressed, and spark plasma sintered to obtain an ingot, wherein the ball-to-material ratio of the ball-milling mixture was 5:1, the rotation speed was 300 rpm, the time was 2 h, the isostatic pressing pressure was 200 MPa, and the spark plasma sintering pressure was 50 MPa, the temperature was 550°C, the heat preservation was 2 h, and the pulse current on-off ratio was 10:1;

[0034] (5) The ingot prepared in step (4) was kept in a heating furnace at 850°C for 2 hours and then hot-extruded into a diameter of finally drawn into the finished wire material of the required specifications and processed into contacts of the required shape and specifications.

[0035] Example 2:

[0036] This embodiment is carried out according to the following steps:

[0037] (1) Cs2CO3 and PbBr2 were dissolved in a mixed solvent of octadecene and oleic acid, heated in an oil bath under nitrogen protection, cooled and centrifuged to obtain quantum dots with surface modification of oleic acid / oleylamine, wherein the reaction temperature was 150°C and the reaction time was 2 h;

[0038] (2) The quantum dots prepared in step (1) were mixed with SnCl4·5H2O in a mass ratio of 1:10 and added to ethanol, and ultrasonically dispersed and spray-dried to obtain a SnO2 / CsPbBr3 precursor, wherein the ultrasonic dispersion temperature was 35°C, the time was 30 min, and the spray drying pressure was 35 MPa;

[0039] (3) 30 kg of silver ingots, tin ingots, indium, and manganese were melted and atomized in a mass ratio of 88:8:3:1, dried, oxidized with special powders, and sieved to obtain a mixed metal powder, wherein the special powder oxidation temperature was 700 ° C, the oxidation pressure was 0.6-1.5 MPa, and the oxidation time was 54 h;

[0040] (4) The SnO2 / CsPbBr3 precursor of step (2) and the mixed metal powder prepared in step (3) were ball-milled in a mass ratio of 1:6, isostatically pressed, and spark plasma sintered to obtain an ingot, wherein the ball-to-material ratio of the ball-milling mixture was 5:1, the rotation speed was 300 rpm, the time was 2 h, the isostatic pressing pressure was 200 MPa, and the spark plasma sintering pressure was 50 MPa, the temperature was 550°C, the heat preservation was 2 h, and the pulse current on-off ratio was 10:1;

[0041] (5) The ingot prepared in step (4) was kept in a heating furnace at 850°C for 2 hours and then hot-extruded into a diameter of finally drawn into the finished wire material of the required specifications and processed into contacts of the required shape and specifications.

[0042] Example 3:

[0043] This embodiment is carried out according to the following steps:

[0044] (1) Cs2CO3 and PbBr2 were dissolved in a mixed solvent of octadecene and oleic acid, heated in an oil bath under nitrogen protection, cooled and centrifuged to obtain quantum dots with surface modification of oleic acid / oleylamine, wherein the reaction temperature was 150°C and the reaction time was 2 h;

[0045] (2) The quantum dots prepared in step (1) were mixed with SnCl4·5H2O in a mass ratio of 1:10 and added to ethanol, and ultrasonically dispersed and spray-dried to obtain a SnO2 / CsPbBr3 precursor, wherein the ultrasonic dispersion temperature was 35°C, the time was 30 min, and the spray drying pressure was 35 MPa;

[0046] (3) 30 kg of silver ingots, tin ingots, manganese, and germanium were melted and atomized in a mass ratio of 90:8:1:1, dried, oxidized with special powders, and sieved to obtain a mixed metal powder, wherein the special powder oxidation temperature was 700°C, the oxidation pressure was 0.6-1.5 MPa, and the oxidation time was 54 h;

[0047] (4) The SnO2 / CsPbBr3 precursor of step (2) and the mixed metal powder prepared in step (3) were ball-milled in a mass ratio of 1:6, isostatically pressed, and spark plasma sintered to obtain an ingot, wherein the ball-to-material ratio of the ball-milling mixture was 5:1, the rotation speed was 300 rpm, the time was 2 h, the isostatic pressing pressure was 200 MPa, and the spark plasma sintering pressure was 50 MPa, the temperature was 550°C, the heat preservation was 2 h, and the pulse current on-off ratio was 10:1;

[0048] (5) The ingot prepared in step (4) was kept in a heating furnace at 850°C for 2 hours and then hot-extruded into a diameter of finally drawn into the finished wire material of the required specifications and processed into contacts of the required shape and specifications.

[0049] Comparative Example 1:

[0050] This comparative example was carried out according to the following steps:

[0051] (1) A total of 30 kg of silver ingots, tin ingots, indium, and germanium were melted and atomized in a mass ratio of 85:12:2:1, dried, oxidized with special powders, and sieved to obtain a mixed metal powder, wherein the special powder oxidation temperature was 700°C, the oxidation pressure was 0.6-1.5 MPa, and the oxidation time was 54 h;

[0052] (2) The mixed metal powder prepared in step (1) was subjected to ball milling, isostatic pressing, and spark plasma sintering to obtain an ingot, wherein the ball-to-material ratio of the ball milling was 5:1, the rotation speed was 300 rpm, the time was 2 h, the isostatic pressing pressure was 200 MPa, and the spark plasma sintering was performed at a pressure of 50 MPa, a temperature of 550° C., a holding time of 2 h, and a pulse current on-off ratio of 10:1;

[0053] (3) The ingot prepared in step (2) was kept in a heating furnace at 850°C for 2 hours and then hot-extruded into a diameter of finally drawn into the finished wire material of the required specifications and processed into contacts of the required shape and specifications.

[0054] The extruded wires in the above implementation did not break during the drawing process, and the minimum specification reached The processability is excellent, essentially meeting all current wire material requirements. The sample prepared in Example 1 exhibited a wire contact resistance of 1.2 μΩ·cm (compared to 1.8 μΩ·cm for the undoped sample in Comparative Example 1); arc resistance of 15,000 times (compared to 12,000 times for the undoped sample in Comparative Example 1); and a resistance change rate of 2.7% after aging at 200°C for 1,000 hours (compared to 8.2% for the undoped sample in Comparative Example 1).

[0055] The products of the above embodiments were hammered into rivet contacts, and no rivet cracking occurred during the hammering process, demonstrating that the processing performance met the requirements for rivet hammering. Finally, the rivet contacts were assembled into relay products and subjected to electrical performance tests under sealing test conditions: 250VAC, 5A, closing force of 100g, breaking force of 60g, and contact frequency of 60 times / minute; and 20VDC, 10A, closing force of 100g, breaking force of 50g, and contact frequency of 60 times / minute. The specific results are shown in Table 1 below. As can be seen, the contact resistance and electrical life cycles of the three embodiments were superior to those of the comparative example.

[0056] Table 1 Comparison of electrical properties of different embodiments and comparative examples

[0057]

Claims

1. A method for preparing a silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots, characterized in that The following steps are involved: Step (1): dissolving Cs2CO3 and PbBr2 in a mixed solvent of octadecene and oleic acid, heating the mixture in an oil bath under nitrogen protection, cooling the mixture and centrifuging the mixture to obtain quantum dots with surface modification of oleic acid / oleylamine; Step (2): adding the quantum dots prepared in step (1) and SnCl4·5H2O to ethanol, mixing, ultrasonically dispersing, and spray drying to obtain a SnO2 / CsPbBr3 precursor; Step (3): The silver ingot, tin ingot and additives are melted, atomized, dried and oxidized to obtain a mixed metal powder; Step (4): ball-milling the SnO2 / CsPbBr3 precursor of step (2) and the mixed metal powder prepared in step (3), isostatically pressing the mixture, and then obtaining an ingot by spark plasma sintering. Step (5): hot-extrude the ingot prepared in step (4) into a wire, and finally draw it into a finished wire of desired specifications.

2. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: In step (1), the reaction temperature is 150-200° C. and the reaction time is 2-4 h.

3. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: In step (2), the ultrasonic dispersion temperature is 30-60° C. and the time is 15-60 min.

4. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: In step (2), the spray drying pressure is 20-50 MPa.

5. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: In step (3), the composition and content of the mixed metal powder are as follows: the mass percentage of silver is 85% to 90%, the mass percentage of tin is 5% to 15%, and the remainder is additives, wherein the additives are two or more of indium, germanium, manganese, cobalt, and titanium.

6. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: In step (4), the ball milling mixing parameters are a ball-to-material ratio of 5:1, a rotation speed of 300 rpm, a time of 2 h, an isostatic pressing pressure of 200-300 MPa, a spark plasma sintering pressure of 30-50 MPa, a temperature of 400-600°C, a heat preservation time of 1-2 h, and a pulse current on-off ratio of 10:

1.

7. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: In the ingot prepared in step (4), the mass percentage of CsPbBr3 quantum dots is 0.5% to 5%.

8. The method for preparing a silver tin oxide electrical contact material based on CsPbBr3 quantum dots doped according to claim 1, characterized in that: Step (5) is performed with the heating parameters of 800°C to 880°C and a holding time of 1 to 3 hours, followed by hot extrusion into a diameter of of extruded wire.

9. A silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots, prepared by the method for preparing a silver tin oxide electrical contact material based on doped CsPbBr3 quantum dots according to any one of claims 1 to 8.

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