Preparation method of tin oxide reinforced silver-based composite material with high strength and high anti-electricity corrosion

Abstract

The application discloses a preparation method of a high-strength high-anti-electricity-erosion tin oxide reinforced silver-based composite material. The application provides a modified tin oxide reinforced phase structure design concept with oxidation reaction characteristics and a preparation method of the high-strength high-anti-electricity-erosion silver-based composite material. The method starts from the reinforced phase structure design concept, introduces a trace amount of oxidizing agent, controls the oxidation reaction condition, obtains the tin oxide reinforced silver-based composite material with strong interface combination, improves the mechanical properties of the silver-based composite material, solves the problems of low strength and poor anti-arc erosion capacity of the silver-based composite material prepared by the traditional powder metallurgy method, and provides reference value for developing the high-strength high-anti-electricity-erosion silver-based composite material.

Description

TECHNICAL FIELD

[0001] The present application relates to the design of a reinforcing phase structure and a new technology for preparing a silver-based composite material, in particular, a method for preparing a high-strength and high-anti-electric-erosion tin oxide reinforced silver-based composite material modified by a trace amount of oxidizing agent, which is applied in the fields of nano electrical contact, new energy low-voltage switchgear, etc. BACKGROUND

[0002] Compared with alternating current transmission, direct current transmission has the advantages of high energy utilization rate, stable power transmission, and no electromagnetic radiation pollution. Direct current relays, direct current contactors, direct current fuses, and other direct current electrical devices for direct current transmission are important components in the fields of photovoltaic energy storage, data centers, and rail transit vehicles, and the key to ensuring their safe and reliable operation lies in the development of corresponding high-performance silver-based composite materials.

[0003] With the development of direct current electrical devices towards small size and high performance, the problems of low mechanical properties and poor anti-electric erosion ability of traditional silver metal oxide composite materials during service are more prominent. Therefore, the performance requirements of silver metal oxide materials for direct current electrical devices gradually develop towards high strength and toughness and high anti-electric erosion, that is, they have not only high strength and toughness mechanical properties but also excellent anti-arc erosion ability, which poses new challenges to the mechanical properties such as tensile strength and hardness of silver-based electrical contact materials for direct current electrical devices and the anti-arc erosion properties such as cycle life. SUMMARY

[0004] In view of the key problems of low mechanical properties and poor anti-electric erosion ability of existing Ag / SnO2 materials applied in direct current electrical devices, the present application provides a modified tin oxide reinforcing phase structure design concept with oxidation reaction characteristics and a method for preparing a high-strength and high-anti-electric-erosion silver-based composite material. Starting from the design concept of the reinforcing phase structure, the method introduces a trace amount of oxidizing agent to control the oxidation reaction conditions, obtains a tin oxide reinforced silver-based composite material with strong interfacial bonding, improves the mechanical properties and service life of the silver-based composite material, effectively solves the problems of low strength and poor anti-arc erosion ability of traditional powder metallurgy Ag / SnO2 composite materials, and provides reference value for the development of high-strength and high-anti-electric-erosion silver-based composite materials.

[0005] To solve the above technical problems, the technical solution adopted by the present application is as follows:

[0006] A method for preparing a high-strength and high-anti-electric-erosion tin oxide reinforced silver-based composite material, comprising the following steps:

[0007] (1) Preparation of a trace amount of oxidizing agent MeO modified tin oxide reinforced silver-based composite powder

[0008] The Ag and SnO powders with a mass ratio of (86-80):(14-20) are mixed and ball milled in a planetary ball mill for 5-10 hours, the ball milling speed is 150-350 rpm, the ball-to-material ratio is (2-8):1, high-purity argon is used as the protective atmosphere, a trace amount of oxidant MeO is introduced, wherein MeO is one or both of FeO and WO2, the amount of MeO is 0.05%-0.5%, and an appropriate amount of anhydrous ethanol (AR, ≥99.7%) is added as a process control agent to ensure that the entire ball milling material is in a fluid slurry state. After ball milling, the MeO modified tin oxide reinforced silver-based composite powder is obtained.

[0009] (II) Preparation of the high-strength high-arc-erosion-resistant silver-based composite material

[0010] (1) The prepared MeO modified AgSnO2 composite powder is loaded into a cylindrical stainless steel mold with a diameter of 40 mm and a height of 100 mm, and is pressed under a hydraulic pressure of 3-9 MPa for 20-60 s, and the obtained ingot is placed in a vacuum tube furnace and reacted and sintered at 500-800 ℃ for 4-10 h. During the reaction sintering process, the AgSnO2 ingot reacts in situ under the action of a trace amount of oxidant to form a high-interface-bonding MeO modified Ag / SnO2 composite sintered ingot. The vacuum degree is maintained at 10 -1 MPa during the sintering process, which can reduce the pollution of harmful components (water, oxygen, nitrogen and other impurities, etc.) in the atmosphere to the material, avoid a series of reactions such as decarburization and carburization, and has a lower vacuum sintering temperature than the gas protection sintering mode, which is beneficial to reduce energy consumption and prevent grain coarsening, so as to ensure the consistency and uniformity of the ingot sintering structure

[0011] (2) The obtained MeO modified Ag / SnO2 composite sintered ingot is prepared into Ag / SnO2 extruded wire with a diameter of 2.5 mm by hot extrusion process under a hydraulic pressure of 5 MPa, and the corresponding hot extrusion temperature is 400-600 ℃.

[0012] (3) The Ag / SnO2 extruded wire is subjected to a 4-pass cumulative cold drawing process to prepare the high-strength high-arc-erosion-resistant silver-based composite material, which is a modified Ag / SnO2 electrical contact material, i.e., the high-strength high-arc-erosion-resistant tin oxide reinforced silver-based composite material. The deformation amount of each pass is 12%, and stress relief annealing is performed during each pass: annealing temperature 540-680 ℃, annealing time 30-60 min. Finally, a silver-based composite material with a small diameter of φ1.3 mm and a rivet product are developed, and their strength and arc erosion resistance are comprehensively evaluated according to the industry standard test requirements.

[0013] The inventive principle of the present application is:

[0014] The method of the application proposes to use Ag and SnO powder as a precursor, add a trace amount of a multivalent oxidizing agent MeO, and use in-situ oxidation reaction combined with hot extrusion technology to prepare high dispersion type Ag / SnO2 composite materials with strong interface bonding. Compared with traditional powder metallurgy technology, the tensile strength, arc erosion resistance and other aspects are greatly improved, the service problems of traditional Ag / SnO2 materials such as low mechanical properties and poor arc erosion resistance are solved, the tensile strength and service life of the material are improved, and the engineering application of small volume DC electrical appliances in photovoltaic energy storage, data center, rail transit vehicles and other fields is expected to be realized.

[0015] The beneficial effects of the application are:

[0016] (1) The application proposes a new strategy for controlling the microstructure and service performance of tin oxide reinforced silver-based composite materials with strong interface bonding and uniform dispersion. The strategy uses Ag and SnO as the basic raw materials, introduces a trace amount of oxidizing agent, and uses mechanical chemical method to construct a trace amount of MeO modified tin oxide reinforced silver-based composite powder by in-situ reaction synthesis. Then, the AgSnO2 compression ingot undergoes in-situ oxidation reaction under the action of trace amount of oxidizing agent, forming a high interface bonding Ag / SnO2 composite sintered ingot. The corresponding extruded wire is obtained by hot extrusion process, and then a high dispersion type MeO modified Ag / SnO2 composite material is prepared by cumulative cold drawing process, realizing stable and controllable preparation.

[0017] (2) The application can batch produce high dispersion strengthened tin oxide reinforced silver-based composite materials with high strength, high arc erosion resistance and other properties, solving the engineering application problems of traditional Ag / SnO2 materials such as low plasticity and short service life, and providing reference value for the industrialization process of high strength and high corrosion resistance Ag / SnO2 materials. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The strength and arc erosion resistance performance curves of the modified Ag / SnO2 composite material prepared in Example 3 are shown in Figure 1. Figure 1(a) is the contact resistance of the trace amount of oxidizing agent modified tin oxide reinforced silver-based composite material, Figure 1(b) is the tensile strength, and Figures 1(c) and 1(d) are the cross section and longitudinal section of the dispersion structure. DETAILED DESCRIPTION

[0019] The implementation mode of the application will be described in detail below with reference to specific examples.

[0020] Example 1:

[0021] (I) Preparation of FeO modified AgSnO2 composite powder

[0022] The Ag and SnO powders with a mass ratio of 80:20 were mixed and ball milled in a planetary ball mill for 5-10 h, the ball milling speed was 350 rpm, the ball-to-material ratio was 2:1, a trace amount of oxidant FeO was introduced, the amount of FeO was in the range of 0.5%, and an appropriate amount of anhydrous ethanol (AR, ≥99.7%) was added as a process control agent to ensure that the entire ball milling material was in a fluid slurry state. After the ball milling was completed, the FeO modified Ag / SnO2 composite powder was obtained.

[0023] (II) Preparation of high-strength and high-anti-electricity-erosion silver-based composite material

[0024] (1) The prepared modified Ag / SnO2 composite powder was loaded into a cylindrical stainless steel mold with a diameter of 40 mm and a height of 100 mm, and was pressed under a hydraulic pressure of 3 MPa for 60 s. The obtained AgSnO2 pressed ingot was placed in a vacuum tube furnace and reacted and sintered at 500 ℃ for 10 h. After the reaction sintering treatment, a FeO modified Ag / SnO2 composite sintered ingot with strong interfacial bonding and uniform and dispersed microstructure was obtained.

[0025] (2) The obtained FeO modified Ag / SnO2 ingot was prepared into a modified Ag / SnO2 extruded wire with a diameter of 2.5 mm by a hot extrusion process under a hydraulic pressure of 5 MPa, and the corresponding hot extrusion temperature was 400 ℃.

[0026] Example 2:

[0027] (I) Preparation of WO2 modified AgSnO2 composite powder

[0028] The Ag and SnO powders with a mass ratio of 86:14 were mixed and ball milled in a planetary ball mill for 10 h, the ball milling speed was 150 rpm, the ball-to-material ratio was 8:1, a trace amount of oxidant WO2 was introduced, the amount of WO2 was in the range of 0.05%, and an appropriate amount of anhydrous ethanol (AR, ≥99.7%) was added as a process control agent to ensure that the entire ball milling material was in a fluid slurry state. After the ball milling, the WO2 modified AgSnO2 composite powder was obtained.

[0029] (II) Preparation of high-strength and high-anti-electricity-erosion silver-based composite material

[0030] (1) The prepared WO2 modified AgSnO2 composite powder was loaded into a cylindrical stainless steel mold with a diameter of 40 mm and a height of 100 mm, and was pressed under a hydraulic pressure of 3 MPa for 60 s. The obtained AgSnO2 pressed ingot was placed in a vacuum tube furnace and reacted and sintered at 500 ℃ for 10 h. After the reaction sintering treatment, a WO2 modified Ag / SnO2 composite sintered ingot with high interfacial bonding was obtained.

[0031] (2) The obtained WO2 modified Ag / SnO2 ingot is prepared into a modified Ag / SnO2 extruded wire with a diameter of 2.5 mm by a hot extrusion process under a hydraulic pressure of 5 MPa, and the corresponding hot extrusion temperature is 500°C.

[0032] Example 3

[0033] (I) Preparation of (WO2, FeO) modified AgSnO2 composite powder

[0034] Ag and SnO powders with a mass ratio of 84:16 are mixed and ball milled in a planetary ball mill for 5-10 h, the ball milling speed is 300 rpm, the ball-to-material ratio is 4:1, a trace amount of oxidant MeO is introduced, wherein MeO is a combination of FeO and WO2, the amount of MeO ranges from 0.2%, and the molar ratio between FeO and WO2 is 3:1; and an appropriate amount of anhydrous ethanol (AR, ≥99.7%) is added as a process control agent to ensure that the entire ball milling material is in a fluid slurry state. After ball milling, the (WO2, FeO) modified AgSnO composite powder is obtained.

[0035] (II) Preparation of high-strength and high-anti-corrosion silver-based composite material

[0036] (1) The prepared (WO2, FeO) modified AgSnO2 composite powder is loaded into a cylindrical stainless steel mold with a diameter of 40 mm and a height of 100 mm, and is pressed under a hydraulic pressure of 3 MPa for 60 s. The obtained modified AgSnO2 ingot is placed in a vacuum tube furnace and reacted and sintered at 500°C for 10 h. After the reaction sintering treatment, a (WO2, FeO) modified Ag / SnO2 composite sintered ingot with high interfacial bonding is formed.

[0037] (2) The obtained (WO2, FeO) modified Ag / SnO2 ingot is prepared into a modified Ag / SnO2 extruded wire with a diameter of 2.5 mm by a hot extrusion process under a hydraulic pressure of 5 MPa, and the corresponding hot extrusion temperature is 600°C.

[0038] Example 4

[0039] (I) Preparation of (WO2, FeO) modified AgSnO2 composite powder

[0040] Ag and SnO powders with a mass ratio of 85:15 were mixed and ball milled in a planetary ball mill for 5 h at a ball milling speed of 280 rpm, a ball-to-material ratio of 3:1, and a trace amount of an oxidizing agent MeO, wherein MeO is a combination of FeO and WO2, the amount of MeO ranges from 0.2%, the molar ratio between FeO and WO2 is (1:1; and an appropriate amount of anhydrous ethanol (AR, ≥99.7%) was added as a process control agent to ensure that the entire ball milling material was in a fluid slurry state. After ball milling, a (WO2, FeO) modified AgSnO composite powder was obtained.

[0041] (II) Preparation of high-strength and high-anti-electricity-erosion silver-based composite materials

[0042] (1) The prepared (WO2, FeO) modified AgSnO composite powder was loaded into a cylindrical stainless steel mold with a diameter of 40 mm and a height of 100 mm, and was pressed under a hydraulic pressure of 3 MPa for 60 s. The obtained ingot was placed in a vacuum tube furnace and reacted and sintered at 500 ℃ for 10 h. After the reaction sintering treatment, a (WO2, FeO) modified AgSnO composite sintered ingot with high interfacial bonding was formed.

[0043] (2) The obtained (WO2, FeO) modified AgSnO ingot was prepared into a modified Ag / SnO2 extruded wire with a diameter of 2.5 mm by a hot extrusion process under a hydraulic pressure of 5 MPa, and the corresponding hot extrusion temperature was 500 ℃.

[0044] Finally, the modified Ag / SnO2 extruded wire prepared in the above Examples 1-4 was subjected to a 4-pass cumulative cold drawing process to prepare a corresponding modified Ag / SnO2 contact new material. In the first to fourth passes, the deformation amount of each pass was 12%, and during this period, stress relief annealing was performed in each pass: annealing temperature 540 ℃, annealing time 60 min. Finally, a small-diameter silver-based composite material and its rivet product were developed, and their strength and DC electrical life performance were comprehensively evaluated according to the national standard GB / T10408.2.

[0045] Table 1 Tensile strength and electrical life performance of modified tin oxide reinforced silver-based composite materials

[0046]

[0047] The comparative analysis of the performance of the modified Ag / SnO2 composite material prepared by Examples 1-4 and the traditional Ag / SnO2 (see Table 1) shows that the performance of the silver-based contact material prepared in Examples 1-4 is significantly improved compared with the traditional Ag / SnO2 material. In particular, the high dispersion type composite microstructure can be prepared by the technical solution of Example 3 (WO2 and FeO co-modification), and a high-strength long-life modified tin oxide reinforced silver-based composite material is obtained.

[0048] Figure 1 The strength and arc erosion resistance performance curve of the modified Ag / SnO2 composite material prepared by Example 3 of the present application is shown. Figure 1 As can be seen from (a) in the figure, the average contact resistance of the sample is 50 mΩ, the joule heating effect of the sample surface is low, and the trend remains stable during the cycle, which is conducive to maintaining the thermal stability of the sample; as can be seen from (b) in the figure, Figure 1 As can be seen from (b) in the figure, the tensile strength of the sample is as high as 355 MPa, and it has good arc impact resistance, which can significantly prolong the service life; Figure 1 (c) and Figure 1 (d) can be seen, the cross-sectional and longitudinal microstructure of the sample is fine and uniform, and the reinforcing phase particles are uniformly dispersed in the silver matrix, which is conducive to maintaining the consistency and uniformity of the sample performance, and also helps to ensure reliable service capability. It is due to the stable contact resistance and high tensile strength, and the fine and uniform microstructure that the arc erosion resistance of the sample is enhanced, and the service life of the sample is prolonged.

[0049] The present application can effectively solve the performance problems of the traditional Ag / SnO2 material, such as low strength and short service life, and can realize macro-stable and controllable production, providing reference value for promoting the industrialization process of high-strength and high-erosion-resistant tin oxide reinforced silver-based composite material.

Claims

1. A method for preparing a high-strength, high-electro-erosion-resistant tin oxide-reinforced silver-based composite material, characterized in that, The steps are as follows: (1) MeO modified tin oxide reinforced silver-based composite powder is pressed under hydraulic pressure of 3-9 MPa for 20-60s, and the resulting ingot is continuously reacted and sintered under vacuum conditions at 500-800℃ for 4-10h to form a MeO modified Ag / SnO2 composite sintered ingot with high interfacial bonding. (2) The MeO modified Ag / SnO2 composite sintered ingot obtained in step (1) was used to prepare Ag / SnO2 extruded wire with a diameter of 2.5 mm by hot extrusion process; (3) The Ag / SnO2 extruded wire obtained in step (2) is subjected to a cumulative cold drawing process of 4 passes to prepare the tin oxide reinforced silver-based composite material; In step (1), the preparation method of the MeO-modified tin oxide-reinforced silver-based composite powder is as follows: Ag and SnO powders in a mass ratio of (86-80):(14-20) were mixed and ball-milled for 5-10 hours at a speed of 150-350 rpm and a ball-to-powder ratio of (2-8):

1. During the ball milling process, high-purity argon was used as a protective atmosphere, and a trace amount of oxidant MeO was introduced, wherein MeO was one or both of FeO and WO2, and the amount of MeO used ranged from 0.05% to 0.5% of the total mass of Ag and SnO powders. Anhydrous ethanol was added as a process control agent to ensure that the entire ball-milled material was in a fluid slurry state. After ball milling, MeO-modified tin oxide-reinforced silver-based composite powder was obtained. In step (3), the cumulative cold drawing process of the four passes is as follows: the deformation of each pass is 12%, and each pass is subjected to stress-relief annealing: annealing temperature is 540-680℃, and annealing time is 30-60min.

2. The method for preparing the high-strength, high-electro-erosion-resistant tin oxide-reinforced silver-based composite material according to claim 1, characterized in that, In step (1), the vacuum condition specifically refers to a vacuum degree of 10. -1 MPa.

3. The method for preparing the high-strength, high-electro-erosion-resistant tin oxide-reinforced silver-based composite material according to claim 1, characterized in that, In step (2), the temperature of the hot extrusion process is 400-600℃.

Images