A material transfer resistant AgNi / AgSnO2 heterolayer electrical contact material and its preparation method

Abstract

The application discloses an AgNi / AgSnO2 hetero-layer contact material resistant to material transfer, which is a hetero-layer structure with AgNi layers and AgSnO2 layers arranged alternately, the total layer number is 2-6, and the single layer thickness is 100-400 microns; the AgNi layer is connected with a substrate; and the application also provides a preparation method of the material, which includes two process routes, route one including calculating mass, then weighing, ultrasonic dispersion, heating mechanical stirring, annealing, layering, twice pressing and thrice sintering; and route two including calculating mass, then weighing, ultrasonic dispersion, ball milling, layering, thrice pressing, thrice sintering and rolling. The application solves the problem of serious material transfer of AgNi under the premise of maintaining the excellent performance of AgNi by constructing a hetero-layer structure, in which the AgNi of the surface layer is responsible for corrosion resistance, and the AgSnO2 layer inhibits the protrusion height and the growth of etch pits.

Description

Technical Field

[0001] This invention belongs to the field of electrical contact materials technology, specifically relating to an AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer and its preparation method. Background Technology

[0002] Silver-based contacts are indispensable materials for controlling the on / off state of current in the field of low-voltage electrical appliances. Due to the poor resistance of pure silver contacts to arc erosion, silver-based electrical contact materials such as AgNi, AgCdO, and AgSnO2 have been developed.

[0003] Traditional AgCdO electrical contact materials possess excellent resistance to arc erosion, material transfer, and welding performance; however, their use is gradually being banned due to the toxicity of Cd. AgSnO2 has become the most promising alternative to AgCdO, exhibiting excellent resistance to arc erosion and material transfer. However, SnO2 tends to accumulate on the eroded surface, leading to increased contact resistance. AgNi electrical contact materials, with their excellent resistance to arc erosion and low, stable contact resistance, are irreplaceable under low loads. However, under certain loads, AgNi electrical contact materials are prone to material transfer, resulting in raised pits on both the moving and stationary contacts. The continuous growth of these raised pits and erosion leads to insufficient effective breaking distance, preventing proper current disconnection and posing a serious risk to the reliability and stability of the electrical system.

[0004] Therefore, suppressing material transfer in AgNi electrical contact materials plays an important role in improving the service life of AgNi contacts. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing an AgNi / AgSnO2 heterolayer electrical contact material that resists material transfer. This material, through the construction of an AgNi / AgSnO2 heterolayer structure, uses the surface AgNi layer for direct contact, resisting erosion and maintaining low contact resistance. When material transfer reaches a certain depth, the AgSnO2 layer inhibits further growth in protrusion height and pit depth. Simultaneously, the diffusion amount of Sn in the eroded layer is controlled by the heterolayer thickness, minimizing the negative impact of SnO2 on contact resistance, thereby fundamentally solving the material transfer problem of AgNi contacts.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is: an AgNi / AgSnO2 heterogeneous layered electrical contact material resistant to material transfer, wherein the electrical contact material is a heterogeneous layered structure in which AgNi layers and AgSnO2 layers are arranged alternately, with a total number of layers of 2 to 6 layers and a single layer thickness of 100 μm to 400 μm, and the electrical contact material is connected to the substrate through the AgNi layer.

[0007] In this invention, material transfer occurs because, under DC load, when an electric arc occurs, charged particles in the arc undergo polarity-related directional motion, triggering a series of physical and chemical changes on the surfaces of the moving and stationary contacts, resulting in material transfer. Material transfer is related to the service environment, electrical load parameters, and material properties. Adjusting material properties with additives may impair processing performance, increase contact resistance, and alter the transfer tendency caused by load changes. Based on this principle, this invention constructs an AgNi / AgSnO2 heterolayer structure. The surface AgNi layer directly contacts the substrate, providing corrosion resistance and maintaining low contact resistance. When material transfer reaches a certain depth, the AgSnO2 layer inhibits further growth in protrusion height and pit depth. Simultaneously, the heterolayer thickness controls the diffusion of Sn in the eroded layer, minimizing the negative impact of SnO2 on contact resistance. This fundamentally solves the material transfer problem of AgNi contacts, resulting in an AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0008] In this invention, the total number of layers and the thickness of each layer are controlled to meet the usage requirements under different load conditions. When the number of layers is small, the thickness of each layer is large. At this time, although the material can play a role in reducing material transfer, the self-triggered threshold is high, and protrusions and pits are limited to a large level. However, the Sn content entering the eroded layer is small, and the effect of maintaining low contact resistance is more significant. When the number of layers is large, the thickness of each layer is small. At this time, the triggering threshold for limiting material transfer is low, and protrusions and pits are limited to a small level. However, there is a risk that Sn elements enter the eroded layer more, increasing the contact resistance. In actual use, the appropriate number of layers and layer thickness should be selected according to the service characteristics of different operating conditions.

[0009] In this invention, electrical contact materials are connected to a substrate as needed, the substrate including a copper or other metal base or a spring sheet.

[0010] The aforementioned silver-based electrical contact material for resisting material transfer comprises an AgNi layer composed of the following mass percentages: Ni 8%~20%, with the balance being Ag; an AgSnO2 layer composed of the following mass percentages: SnO2 8%~20%, with the balance being Ag; and an electrical contact material composed of the following mass percentages: SnO2 4%~16%, Ni 4%~16%, with the balance being Ag. The key to this invention lies in using different material layers in a spatial arrangement to hinder material transfer, thus allowing compatibility with material layers of varying proportions. The material composition design is also intended to meet the usage requirements under different load conditions. Different Ni contents result in significant differences in the material's resistance to arc erosion; the Ni content can be adjusted according to actual operating conditions. Furthermore, different SnO2 contents also result in significant differences in the resistance to material transfer under different operating conditions, and SnO2, existing in the subsurface layer, has a relatively small impact on contact resistance. Therefore, the combination of Ni and SnO2 contents can be determined based on actual usage.

[0011] In addition, the present invention also provides a method for preparing AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer, the method comprising the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate, as well as the thickness and composition of each layer of the electrical contact material, and combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder and SnO2 powder for each layer according to the mass calculated in Step 1, and obtain the raw material powder for each layer. Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then heat and mechanically stir until the ethanol evaporates, and finally grind it to obtain the composite powder of each layer. Step 4: Anneal the composite powder obtained in Step 3 for each layer, and then grind it to obtain annealed powder for each layer. Step 5: Load the first layer of annealed powder from each layer of annealed powder obtained in Step 4 into the mold, then place the upper pressure head and apply vibration to the entire mold. Then load the second layer of annealed powder into the mold, then place the upper pressure head and apply vibration to the entire mold. Repeat the above process until each layer of powder is loaded into the mold to obtain a mold with annealed powder. Step 6: Pre-press the mold containing annealed powder obtained in Step 5, and then demold it to obtain a pressed blank; Step 7: The pressed blank obtained in Step 6 is sintered for the first time under inert gas protection to obtain a sintered block; Step 8: Press the sintered block obtained in Step 7 into shape, then demold it to obtain a dense block. Step 9: The dense bulk material obtained in Step 8 is sintered a second time under inert gas protection to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0012] In this invention, the required mass of Ag powder, Ni powder, and SnO2 powder for each layer is calculated and weighed to obtain the raw material powder for each layer. Then, ethanol is added and ultrasonically dispersed evenly, followed by heating and mechanical stirring until the ethanol evaporates to prevent the reinforcing phase powder from agglomerating again due to gravity or buoyancy during the viscous stage of the mixture. Annealing is performed to increase the powder flowability. The original powder contains irregular and extremely fine particles, resulting in poor powder flowability, making it difficult to ensure complete powder spreading during layering. Therefore, powder annealing is used to grow excessively fine particles and eliminate particle edges. Grinding is then used to further improve powder flowability. Two pressing and two sintering processes are used: pre-pressing and the first sintering are performed at low pressure and high temperature to degas and allow for sintering neck growth; pressing and the second sintering are performed at high pressure and medium temperature to densify and anneal. Through the synergistic effect of pressing and sintering densification and deformation processing, uniform layer thickness is achieved, with each layer thickness approaching the theoretical thickness, resulting in an AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer.

[0013] The method in this invention meets the preparation requirements for laboratory research because when the mold is enlarged to a certain size, the press pressure is insufficient to densify the material, making it unsuitable for mass production. When the amount of material to be prepared exceeds 100 grams or even kilograms, rolling should be used.

[0014] In the above method, the Ag powder in step two is electrical silver powder with an average particle size of 5μm~72μm, the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm, and the mass purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%; the annealing temperature in step four is 500℃~810℃, and the time is 0.5h~2h. In this invention, the average particle size range of the electrical silver powder is a comprehensive consideration of the powder's specific surface area and flowability. If the particle size is too large, the specific surface area is too small, resulting in uneven distribution of the reinforcing phase; if the particle size is too small, the powder flowability is poor, and the sintering activation energy is high, preventing the removal of internal gases and hindering sintering densification. The average particle size of the Ni powder and SnO2 powder takes into account powder dispersibility and the final material's effect on arc dispersion. If the particle size is too fine, the powder dispersibility is poor; if the particle size is too large, the material's effect on arc dispersion is insufficient. The annealing temperature range takes into account variations in silver powder particle size. A reasonable annealing temperature should be selected, as silver powder particle size directly affects the sintering activation energy. Even at the same temperature, there are significant differences in the degree of sintering between powders. The purpose of powder annealing is to allow extremely fine powder to grow while preventing large powder particles from sintering. This makes the resulting annealed mass easier to break and improves flowability. If the annealing temperature is too high, the powder is highly sintered and cannot be broken; if the annealing temperature is too low, the powder is not highly sintered, and annealing fails to improve flowability.

[0015] In the above method, the pre-compression pressure in step six is ​​50MPa~300MPa; the pressing pressure in step eight is 800MPa~1000MPa. In this invention, the pre-compression pressure is relatively low to preserve interconnected pores, which facilitates venting and natural shrinkage. The purpose of pressing is densification, therefore a higher pressure is set. Furthermore, the pressure range is determined based on the total thickness of the powder layer; a lower pressure is preferable for thinner layers, and a higher pressure is preferable for thicker layers.

[0016] In the above method, the heating rate for the first sintering in step seven is 5℃ / min~30℃ / min, the temperature is 700℃~900℃, and the time is 2h~4h; the heating rate for the second sintering in step nine is 5℃ / min~30℃ / min, the temperature is 600℃~700℃, and the time is 1h~2h. In this invention, the heating rate range is set according to the sample size. Larger samples have slower heat conduction and should use a lower heating rate; smaller samples have faster heat conduction and can have a higher heating rate. The temperature range is set according to the reinforcing phase content. When the reinforcing phase content is high, a higher temperature should be selected to eliminate defects as much as possible; when the reinforcing phase content is low, the sintering temperature can be reduced to decrease energy consumption. The holding time is also determined according to the size.

[0017] In addition, the present invention also provides another method for preparing AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer, the method comprising the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate and the thickness and composition of each layer of electrical contact material before and after rolling, combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder and SnO2 powder for each layer according to the mass calculated in Step 1, and obtain the raw material powder for each layer. Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then centrifuge and dry it, and finally grind it to obtain the composite powder of each layer. Step 4: Ball mill the composite powder obtained in Step 3, then dry and grind it to obtain ball-milled powder for each layer. Step 5: Load the first layer of ball mill powder obtained in each layer of ball mill powder in Step 4 into the mold, then put in the upper pressure head and apply vibration to the mold as a whole. Then load the second layer of ball mill powder into the mold, then put in the upper pressure head and apply vibration to the mold as a whole. Repeat the above process until each layer of ball mill powder is loaded into the mold to obtain a mold with ball mill powder. Step 6: Pre-press the mold containing the ball milled powder obtained in Step 5, and then demold it to obtain the pressed blank; Step 7: The pressed blank obtained in Step 6 is sintered for the first time under inert gas protection to obtain a sintered block; Step 8: Perform the first pressure densification deformation on the sintered block obtained in step 7, and then demold to obtain a block with a regular shape; Step 9: The regularly shaped block obtained in Step 8 is sintered a second time under an inert gas protection to obtain sintered block material; Step 10: Perform a second pressure densification deformation on the sintered block material obtained in step 9, and then demold it to obtain a block material with a regular shape; Step 11: The regularly shaped blocks obtained in Step 10 are sintered for the third time under an inert gas protection to obtain sintered blocks; Step 12: Roll the sintered block material obtained in step 11 to obtain AgNi / AgSnO2 heterolayer electrical contact material that resists material transfer.

[0018] In this invention, the required mass of Ag powder, Ni powder, and SnO2 powder for each layer is calculated and weighed to obtain the raw material powder for each layer. Then, ethanol is added and ultrasonically dispersed evenly, followed by centrifugation and drying. The powder flowability is improved by grinding. Centrifugation is suitable for larger quantities of raw material powder, improving production efficiency and reducing ethanol consumption. Ball milling is also suitable for larger quantities of raw material powder, improving production efficiency. Furthermore, through three pressing and three sintering processes, with gradually increasing pressure and constant sintering temperature, the aim is to completely eliminate internal gases in the block, preventing peeling and cracking during thickness processing. Rolling is used as another process route for thinning the sheets, which helps to improve production efficiency.

[0019] The method in this invention meets the preparation requirements for process scale-up.

[0020] In the above method, the Ag powder in step 2 is electrical silver powder with an average particle size of 5μm~72μm, and the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm. The mass purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%. In step 4, the mass ratio of grinding balls, composite powder in each layer and ethanol in the ball mill is 2~4:1:1. The ball milling time is 1h~6h and the rotation speed is 200rpm~300rpm. The ball mill uses a stainless steel tank and stainless steel grinding balls. The stainless steel grinding balls are stainless steel grinding balls with a mass ratio of 1:1:1 and diameters of 3mm~4mm, 4mm~6mm and 6mm~8mm. The filling degree of the stainless steel tank does not exceed 20%. In this invention, the average particle size range of the electrical silver powder is a comprehensive consideration of the powder's specific surface area and flowability. If the particle size is too large, the specific surface area is too small, resulting in uneven distribution of the reinforcing phase; if the particle size is too small, the powder flowability is poor, and the sintering activation energy is high, preventing the removal of internal gases and hindering sintering densification. The average particle size of the Ni powder and SnO2 powder takes into account powder dispersibility and the final material's effect on arc dispersion. If the particle size is too fine, the powder dispersibility is poor; if the particle size is too large, the material's effect on arc dispersion is insufficient. By controlling various parameters of the ball mill, the goal is to maximize the ball milling homogenization effect. The ball-to-material ratio is set to balance dispersibility, impurity introduction, and powder particle deformation, achieving dispersion while controlling powder particle deformation and impurity introduction. Different grinding ball size ratios are used to improve the density of the grinding ball arrangement and enhance the ball milling effect. Controlling the filling degree is to leave sufficient space for the grinding balls to move, ensuring the ball milling dispersion effect.

[0021] In the above method, the pre-pressing pressure in step 6 is 100MPa~200MPa, the primary pressure densification deformation pressure is 300MPa~500MPa, and the secondary pressure densification deformation pressure is 800MPa~1000MPa. In step 12, the deformation amount per rolling pass does not exceed 5%, and after the total deformation amount reaches 30%, annealing is performed at a temperature of 800℃~900℃ for 1h~2h. Rolling deformation continues until the required thickness is achieved. The progressively increasing pressure in the three pressing stages of this invention is to maximize the discharge of internal gas, improve the densification degree, and prevent cracking while meeting the thinning requirements by controlling the rolling parameters.

[0022] In the above method, the heating rate for the first sintering in step 7 is 5℃ / min~10℃ / min, the temperature is 800℃~900℃, and the time is 1h~4h; the heating rate for the second sintering in step 9 is 5℃ / min~10℃ / min, the temperature is 800℃~900℃, and the time is 1h~4h; the heating rate for the third sintering in step 11 is 5℃ / min~10℃ / min, the temperature is 800℃~900℃, and the time is 1h~4h. In this invention, the heating rate range is set according to the sample size. Larger samples have slower heat conduction and should use a lower heating rate; smaller samples have faster heat conduction and can have a higher heating rate. The three sintering temperatures are the same, which, in addition to eliminating defects, ensures equal collision and discharge of internal gases. The holding time is also determined according to the size.

[0023] Compared with the prior art, the present invention has the following advantages: 1. The heterogeneous layered electrical contact material provided by this invention consists of a heterogeneous layer composed of AgNi and AgSnO2 with strong anti-welding properties. When material transfer occurs to the AgSnO2 layer, its material transfer mode changes, preventing the pit from extending further in the depth direction. The advantage of this solution is: (1) Implements "physical barrier" for material transfer, applicable to all load environments; (2) The diffusion of Sn in the etched layer is very limited, and the risk of increased contact resistance is low; (3) It can reduce the redundancy of the opening and closing gaps set to prevent material transfer, which is beneficial to the miniaturization of devices; (4) Significantly improve service life.

[0024] 2. In the preparation method of the present invention, the amount of powder required for each layer in the initial stage is calculated by preset size, and the layer thickness is uniformly reduced by the synergistic effect of pressing and sintering densification and deformation processing. Since the material amount of each layer is controlled with precision at the mg level, the deformation precision is also easy to control. The layer thickness obtained by this method is uniform and consistent, and the sheet material has good processing performance under multiple deformations.

[0025] 3. In the preparation method of the present invention, the powder uniformity is maximized by using a combination of ultrasonic dispersion and ball milling. The purpose of ultrasonic dispersion is to disperse the agglomerated micro-nano and fine particles and to initially mix them with silver powder. Ball milling achieves the control of overall uniformity and achieves uniformly dispersed composite powder by causing the silver powder to deform appropriately and by the pinning or cold welding effect of the second phase on the surface of the silver particles.

[0026] 4. In the preparation method of the present invention, after adding powder to the mold, the upper pressure head is installed to apply vibration to the mold as a whole. The purpose is that under the constraint of the upper pressure head's own gravity, the powder can be neatly arranged according to the shape of the mold, and the powder is also prevented from sticking together at the bottom of the upper pressure head. In addition, such arrangement can compact the powder and prevent excessive diffusion of powder between different heterogeneous layers during the pressing process, thereby affecting the purity within the heterogeneous layers.

[0027] 5. In the preparation method of the present invention, the pressing and sintering are carried out three times, with the pressing force increasing from small to large and the sintering temperature remaining relatively constant. Its advantage is that the internal pores are fully discharged, preventing defects such as bulging of the material during subsequent deformation and annealing.

[0028] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0029] Figure 1 This is a flowchart illustrating the preparation process of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer according to the present invention.

[0030] Figure 2 This is a cross-sectional microstructure diagram of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in Example 1 of the present invention.

[0031] Figure 3 The elemental distribution diagram is shown in the longitudinal section of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in Example 1 of this invention.

[0032] Figure 4 The surface morphology of the AgNi / AgSnO2 heterolayered electrical contact material with anti-material transfer prepared in Example 1 of the present invention after 20,000 electrical contact tests under the same load.

[0033] Figure 5 This is a cross-sectional microstructure diagram of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in Example 2 of the present invention.

[0034] Figure 6 The elemental distribution diagram is shown in the longitudinal section of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in Example 2 of this invention.

[0035] Figure 7 The surface morphology of the AgNi / AgSnO2 heterolayered electrical contact material with anti-material transfer prepared in Example 2 of the present invention after 20,000 electrical contact tests under the same load. Detailed Implementation

[0036] Figure 1 This is a flowchart illustrating the preparation process of the AgNi / AgSnO2 heterolayered electrical contact material with anti-material transfer properties according to the present invention. Figure 1As can be seen from the above, the present invention employs two methods to prepare the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer: The first method involves calculating the required mass of Ag powder, Ni powder, and SnO2 powder for each layer based on the area of ​​the required electrical contact material in the substrate, the layer thickness and composition of each layer, and the densities of the AgNi layer and AgSnO2 layer. The required mass of Ag powder, Ni powder, and SnO2 powder for each layer is then weighed according to the calculated mass. The raw material powder for each layer is added to ethanol, then ultrasonically dispersed until uniform, followed by heating and mechanical stirring until the ethanol evaporates completely. Finally, the mixture is ground, and then the composite powder for each layer is annealed. Then, grinding is performed, followed by layering. The first layer of annealed powder is loaded into the mold (powder loading), then the upper pressure head is placed in and the mold is vibrated, and then the upper pressure head is removed. The second layer of annealed powder is then loaded into the mold, and the upper pressure head is placed in and the mold is vibrated, and then the upper pressure head is removed. This process is repeated until each layer of powder is loaded into the mold. Then, pre-pressing is performed, followed by demolding. The first sintering is carried out under inert gas protection (pressing and sintering), followed by pressing and densification, and then demolding. The second sintering is carried out under inert gas protection (repressing and re-sintering) to obtain AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer. The two methods involve first calculating the required area of ​​the electrical contact material in the matrix, as well as the layer thickness and composition of each layer before and after rolling, combined with the densities of the AgNi and AgSnO2 layers. The required mass of Ag, Ni, and SnO2 powder for each layer is then weighed according to the calculated mass. Ethanol is added to the raw material powder for each layer, followed by ultrasonic dispersion, centrifugation, drying, and finally grinding. Next, ball milling is performed, followed by drying and grinding again. Then, the powder is laid up. The ball-milled powder of the first layer is loaded into a mold (powder loading), and then the upper pressure head is placed in and the mold is vibrated before the upper pressure head is removed. The second layer of ball-milled powder is loaded into the mold, then the upper pressure head is placed in and the mold is vibrated. After removing the upper pressure head, the above process is repeated until each layer of ball-milled powder is loaded into the mold. Then, pre-pressing is performed, followed by demolding. The first sintering is carried out under inert gas protection, i.e., pressing and sintering. Then, the first pressure densification deformation is performed, followed by demolding. The second sintering is carried out under inert gas protection, i.e., repressing and re-firing. Then, the second pressure densification deformation is performed, followed by demolding. The third sintering is carried out under inert gas protection, i.e., repressing and re-firing. Finally, rolling is performed to obtain AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer.

[0037] Example 1 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 8%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 8%, balance Ag; the design has 6 layers, with alternating AgNi and AgSnO2 layers, each layer having a thickness of 100 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 4%, Ni 4%, balance Ag.

[0038] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate, as well as the thickness and composition of each layer of the electrical contact material, and combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, to obtain the raw material powder for each layer; the Ag powder is electrical silver powder with an average particle size of 5μm~72μm, the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm, and the purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%; Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then heat and mechanically stir until the ethanol evaporates, and finally grind it to obtain the composite powder of each layer. Step 4: Anneal the composite powder obtained in Step 3 at 700℃ for 2 hours, and then grind it to obtain the annealed powder of each layer. Step 5: Load the first layer of annealed powder from each layer of annealed powder obtained in Step 4 into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Then load the second layer of annealed powder into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Repeat the above process until each layer of powder is loaded into the mold to obtain a mold with annealed powder. Step 6: Pre-press the mold containing annealed powder obtained in Step 5 under a pressure of 100MPa, and then demold to obtain a pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 800℃ under inert gas protection at a heating rate of 10℃ / min for the first sintering for 2 hours to obtain a sintered block. Step 8: Press the sintered block obtained in Step 7 under a pressure of 850 MPa to densify it, and then demold it to obtain a dense block. Step 9: The dense bulk material obtained in Step 8 is heated to 600℃ for a second sintering at a heating rate of 10℃ / min under inert gas protection for 2 hours to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0039] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0040] Figure 2 This is a cross-sectional microstructure diagram of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment. Figure 3 This is an elemental distribution diagram of the longitudinal section of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment. Figure 2 and Figure 3 As can be seen from the above, the heterolayers of the AgNi / AgSnO2 heterolayered electrical contact material prepared in this embodiment have good bonding and no obvious defects. The Ni and Sn elements are alternately distributed, and the layer thickness is uniform and close to the theoretical value. This proves that the preparation method provided by the present invention can successfully prepare AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer.

[0041] Figure 4 The surface morphology of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment after 20,000 electrical contact tests under the same load is shown. The control group uses conventional AgNi electrical contact material, whose composition is consistent with the AgNi layer composition in the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment. Figure 4 The top two images represent the control group, with the left side being the cathode and the right side the anode. The bottom two images show the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment, with the left side being the cathode and the right side the anode. Figure 4 As can be seen from the data, after the control group underwent electrical contact testing, large, deep, and concentrated pits appeared on the anode surface, and large, high, and concentrated protrusions appeared on the cathode surface, indicating severe material transfer. In contrast, the AgNi / AgSnO2 heterolayered electrical contact material prepared in this embodiment, after electrical contact testing, showed that the size of the protrusions and pits was significantly reduced, indicating a significant anti-material transfer effect.

[0042] Example 2 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 8%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 8%, balance Ag; the design has 2 layers, with the AgNi and AgSnO2 layers alternating, each layer having a thickness of 300 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 4%, Ni 4%, balance Ag.

[0043] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate, as well as the thickness and composition of each layer of the electrical contact material, and combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, to obtain the raw material powder for each layer; the Ag powder is electrical silver powder with an average particle size of 5μm~72μm, the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm, and the purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%; Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then heat and mechanically stir until the ethanol evaporates, and finally grind it to obtain the composite powder of each layer. Step 4: Anneal the composite powder obtained in Step 3 at 700℃ for 2 hours, and then grind it to obtain the annealed powder of each layer. Step 5: Load the first layer of annealed powder from each layer of annealed powder obtained in Step 4 into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Then load the second layer of annealed powder into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Repeat the above process until each layer of powder is loaded into the mold to obtain a mold with annealed powder. Step 6: Pre-press the mold containing annealed powder obtained in Step 5 under a pressure of 100MPa, and then demold to obtain a pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 800℃ under inert gas protection at a heating rate of 10℃ / min for the first sintering for 2 hours to obtain a sintered block. Step 8: Press the sintered block obtained in step 7 under a pressure of 850 MPa to densify it, and then demold it to obtain a dense block. Step 9: The dense bulk material obtained in Step 8 is heated to 600℃ for a second sintering at a heating rate of 10℃ / min under inert gas protection for 2 hours to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0044] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0045] Figure 5 This is a cross-sectional microstructure diagram of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment. Figure 6 This is an elemental distribution diagram of the longitudinal section of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment. Figure 5 and Figure 6 As can be seen from the above, the heterolayers of the AgNi / AgSnO2 heterolayered electrical contact material prepared in this embodiment have good bonding and no obvious defects. The Ni and Sn elements are alternately distributed, and the layer thickness is uniform and close to the theoretical value. This proves that the preparation method provided by the present invention can successfully prepare AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer.

[0046] Figure 7 The surface morphology of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in Example 2 of this invention after 20,000 electrical contact tests under the same load is shown. The control group uses conventional AgNi electrical contact material, whose composition is consistent with the AgNi layer composition in the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this example. Figure 7 The top two images represent the control group, with the left side being the cathode and the right side the anode. The bottom two images show the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment, with the left side being the cathode and the right side the anode. Figure 7 As can be seen from the data, after the control group underwent electrical contact testing, large, deep, and concentrated pits appeared on the anode surface, and large, high, and concentrated protrusions appeared on the cathode surface, indicating severe material transfer. After testing, the AgNi / AgSnO2 heterolayered electrical contact material with anti-material transfer properties prepared in this embodiment showed that the size of the protrusions and pits was significantly reduced, indicating a significant anti-material transfer effect.

[0047] Example 3 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 8%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 8%, balance Ag; the design has 2 layers, with the AgNi and AgSnO2 layers alternating, each layer having a thickness of 300 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 4%, Ni 4%, balance Ag.

[0048] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate, as well as the thickness and composition of each layer of the electrical contact material, and combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, to obtain the raw material powder for each layer; the Ag powder is electrical silver powder with an average particle size of 5μm~72μm, the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm, and the purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%; Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then heat and mechanically stir until the ethanol evaporates, and finally grind it to obtain the composite powder of each layer. Step 4: Anneal the composite powder obtained in Step 3 at 500℃ for 1 hour, and then grind it to obtain the annealed powder of each layer. Step 5: Load the first layer of annealed powder from each layer of annealed powder obtained in Step 4 into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Then load the second layer of annealed powder into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Repeat the above process until each layer of powder is loaded into the mold to obtain a mold with annealed powder. Step 6: Pre-press the mold containing annealed powder obtained in Step 5 under a pressure of 50MPa, and then demold to obtain a pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 700°C under inert gas protection at a heating rate of 5°C / min for the first sintering for 3 hours to obtain a sintered block. Step 8: Press the sintered block obtained in Step 7 under a pressure of 800 MPa to densify it, and then demold it to obtain a dense block. Step 9: The dense bulk material obtained in Step 8 is heated to 650°C for a second sintering at a heating rate of 5°C / min under inert gas protection for 1 hour to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0049] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0050] Example 4 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 16%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 16%, balance Ag; the design has 6 layers, with alternating AgNi and AgSnO2 layers, each layer having a thickness of 100 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 8%, Ni 8%, balance Ag.

[0051] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate, as well as the thickness and composition of each layer of the electrical contact material, and combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, to obtain the raw material powder for each layer; the Ag powder is electrical silver powder with an average particle size of 5μm~72μm, the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm, and the purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%; Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then heat and mechanically stir until the ethanol evaporates, and finally grind it to obtain the composite powder of each layer. Step 4: Anneal the composite powder obtained in Step 3 at 810℃ for 0.5h, and then grind it to obtain the annealed powder of each layer. Step 5: Load the first layer of annealed powder from each layer of annealed powder obtained in Step 4 into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Then load the second layer of annealed powder into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Repeat the above process until each layer of powder is loaded into the mold to obtain a mold with annealed powder. Step 6: Pre-press the mold containing annealed powder obtained in Step 5 under a pressure of 300MPa, and then demold to obtain a pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 900℃ under inert gas protection at a heating rate of 30℃ / min for the first sintering for 4 hours to obtain a sintered block. Step 8: Press the sintered block obtained in Step 7 under a pressure of 1000MPa to densify it, and then demold it to obtain a dense block. Step 9: The dense bulk material obtained in Step 8 is heated to 700°C under inert gas protection at a heating rate of 30°C / min for a second sintering for 1.5 hours to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0052] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0053] Example 5 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 20%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 20%, balance Ag; the design has 4 layers, with alternating AgNi and AgSnO2 layers; the thickness of the AgNi layer is 100 μm; and the thickness of the AgSnO2 layer is 400 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 16%, Ni 4%, balance Ag.

[0054] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate and the thickness and composition of each layer of electrical contact material before and after rolling, combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, to obtain the raw material powder for each layer; the Ag powder is electrical silver powder with an average particle size of 5μm~72μm, the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm, and the purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%; Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then centrifuge and dry it, and finally grind it to obtain the composite powder of each layer. Step 4: Ball mill the composite powder obtained in Step 3 for each layer, then dry and grind it to obtain ball-milled powder for each layer. The mass ratio of grinding balls, composite powder for each layer, and ethanol in the ball mill is 4:1:1. The ball milling time is 4 hours and the rotation speed is 300 rpm. The ball mill uses a stainless steel tank and stainless steel grinding balls. The stainless steel grinding balls are stainless steel grinding balls with diameters of 3mm~4mm, 4mm~6mm, and 6mm~8mm, with a mass ratio of 1:1:1. The filling degree of the stainless steel tank does not exceed 20%. Step 5: Load the first layer of ball mill powder obtained in each layer of ball mill powder in Step 4 into the mold, then put in the upper pressure head and apply vibration to the mold as a whole, and then remove the upper pressure head. Then load the second layer of ball mill powder into the mold, then put in the upper pressure head and apply vibration to the mold as a whole, and then remove the upper pressure head. Repeat the above process until each layer of ball mill powder is loaded into the mold, and obtain a mold with ball mill powder. Step 6: Pre-press the mold containing the ball milled powder obtained in Step 5 under a pressure of 200 MPa, and then demold to obtain the pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 900℃ under inert gas protection at a heating rate of 10℃ / min for the first sintering for 2 hours to obtain a sintered block. Step 8: The sintered block obtained in Step 7 is subjected to the first pressure densification deformation at a pressure of 500 MPa, and then demolded to obtain a block with a regular shape. Step 9: The regularly shaped block obtained in Step 8 is heated to 900℃ under inert gas protection at a heating rate of 10℃ / min for a second sintering for 2 hours to obtain sintered block material; Step 10: The sintered block obtained in Step 9 is subjected to a second pressure densification deformation at a pressure of 1000MPa, and then demolded to obtain a block with a regular shape. Step 11: The regularly shaped blocks obtained in Step 10 are heated to 900°C for a third sintering for 2 hours under inert gas protection at a heating rate of 10°C / min to obtain sintered blocks. Step 12: Roll the sintered block material obtained in Step 11. The deformation amount in a single pass shall not exceed 5%. After the total deformation amount reaches 30%, anneal it at a temperature of 900℃ for 2 hours. Then continue rolling and deformation until the required thickness is reached to obtain AgNi / AgSnO2 heterolayer electrical contact material that resists material transfer.

[0055] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0056] Example 6 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 20%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 20%, balance Ag; the design has 4 layers, with alternating AgNi and AgSnO2 layers; the thickness of the AgNi layer is 400 μm; and the thickness of the AgSnO2 layer is 100 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 4%, Ni 16%, balance Ag.

[0057] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate and the thickness and composition of each layer of electrical contact material before and after rolling, combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, and obtain the raw material powder for each layer. The Ag powder is electrical silver powder with an average particle size of 5μm~72μm, and the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm. The purity of the Ag powder, Ni powder, and SnO2 powder is not less than 99.5%. In Step 4, the mass ratio of grinding balls, composite powder for each layer, and ethanol in the ball mill is 3:1:1. The ball milling time is 1 hour, and the rotation speed is 250 rpm. The ball mill uses a stainless steel tank and stainless steel grinding balls. The stainless steel grinding balls are stainless steel grinding balls with a mass ratio of 1:1:1 and diameters of 3mm~4mm, 4mm~6mm, and 6mm~8mm. The filling degree of the stainless steel tank does not exceed 20%. Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then centrifuge and dry it, and finally grind it to obtain the composite powder of each layer. Step 4: Ball mill the composite powder obtained in Step 3, then dry and grind it to obtain ball-milled powder for each layer. Step 5: Load the first layer of ball mill powder obtained in each layer of ball mill powder in Step 4 into the mold, then put in the upper pressure head and apply vibration to the mold as a whole, and then remove the upper pressure head. Then load the second layer of ball mill powder into the mold, then put in the upper pressure head and apply vibration to the mold as a whole, and then remove the upper pressure head. Repeat the above process until each layer of ball mill powder is loaded into the mold, and obtain a mold with ball mill powder. Step 6: Pre-press the mold containing the ball milled powder obtained in Step 5 under a pressure of 150 MPa, and then demold to obtain the pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 850°C under inert gas protection at a heating rate of 8°C / min for the first sintering for 4 hours to obtain a sintered block. Step 8: The sintered block obtained in Step 7 is subjected to the first pressure densification deformation at a pressure of 400 MPa, and then demolded to obtain a block with a regular shape. Step 9: The regularly shaped block obtained in Step 8 is heated to 850°C under inert gas protection at a heating rate of 8°C / min for a second sintering for 4 hours to obtain sintered block material. Step 10: The sintered block obtained in Step 9 is subjected to a second pressure densification deformation at a pressure of 900 MPa, and then demolded to obtain a block with a regular shape. Step 11: The regularly shaped blocks obtained in Step 10 are heated to 850°C for a third sintering at a heating rate of 8°C / min under inert gas protection for 4 hours to obtain sintered blocks. Step 12: Roll the sintered block material obtained in Step 11. The deformation amount in a single pass shall not exceed 5%. After the total deformation amount reaches 30%, anneal it at a temperature of 850℃ for 1.5 hours. Then continue rolling and deformation until the required thickness is reached to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

[0058] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0059] Example 7 In this embodiment, the AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer consists of the following composition by mass percentage: Ni 8%, balance Ag; the AgSnO2 layer consists of the following composition by mass percentage: SnO2 8%, balance Ag; the design has 3 layers, with the AgNi and AgSnO2 layers alternating, and the AgNi layer consists of two layers. The thickness of the first AgNi layer is 200 μm, the thickness of the second AgSnO2 layer is 300 μm, and the thickness of the third AgNi layer is 100 μm. The AgNi / AgSnO2 heterolayered electrical contact material resisting material transfer according to this ratio consists of the following composition by mass percentage: SnO2 4%, Ni 4%, balance Ag.

[0060] This embodiment includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate and the thickness and composition of each layer of electrical contact material before and after rolling, combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh the required Ag powder, Ni powder, and SnO2 powder for each layer according to the mass calculated in Step 1, and obtain the raw material powder for each layer. The Ag powder is electrical silver powder with an average particle size of 5μm~72μm, and the Ni powder and SnO2 powder have an average particle size of 0.2μm~5μm. The purity of the Ag powder, Ni powder, and SnO2 powder is not less than 99.5%. In Step 4, the mass ratio of grinding balls, composite powder for each layer, and ethanol in the ball mill is 2:1:1. The ball milling time is 2 hours, and the rotation speed is 200 rpm. The ball mill uses a stainless steel tank and stainless steel grinding balls. The stainless steel grinding balls are stainless steel grinding balls with a mass ratio of 1:1:1 and diameters of 3mm~4mm, 4mm~6mm, and 6mm~8mm. The filling degree of the stainless steel tank does not exceed 20%. Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then centrifuge and dry it, and finally grind it to obtain the composite powder of each layer. Step 4: Ball mill the composite powder obtained in Step 3, then dry and grind it to obtain ball-milled powder for each layer. Step 5: Load the first layer of ball mill powder obtained in each layer of ball mill powder in Step 4 into the mold, then put in the upper pressure head and apply vibration to the mold as a whole, and then remove the upper pressure head. Then load the second layer of ball mill powder into the mold, then put in the upper pressure head and apply vibration to the mold as a whole, and then remove the upper pressure head. Repeat the above process until each layer of ball mill powder is loaded into the mold, and obtain a mold with ball mill powder. Step 6: Pre-press the mold containing the ball milled powder obtained in Step 5 under a pressure of 100 MPa, and then demold to obtain the pressed blank; Step 7: The pressed blank obtained in Step 6 is heated to 800℃ under inert gas protection at a heating rate of 5℃ / min for the first sintering for 1 hour to obtain a sintered block. Step 8: The sintered block obtained in Step 7 is subjected to the first pressure densification deformation at a pressure of 300 MPa, and then demolded to obtain a block with a regular shape. Step 9: The regularly shaped block obtained in Step 8 is heated to 800°C for a second sintering at a heating rate of 5°C / min under inert gas protection for 1 hour to obtain sintered block material. Step 10: The sintered block obtained in Step 9 is subjected to a second pressure densification deformation at a pressure of 800 MPa, and then demolded to obtain a block with a regular shape. Step 11: The regularly shaped blocks obtained in Step 10 are heated to 800°C for a third sintering for 1 hour under inert gas protection at a heating rate of 5°C / min to obtain sintered blocks. Step 12: Roll the sintered block material obtained in Step 11. The deformation amount in a single pass shall not exceed 5%. After the total deformation amount reaches 30%, anneal it at a temperature of 800℃ for 1 hour. Then continue rolling and deformation until the required thickness is reached to obtain AgNi / AgSnO2 heterolayer electrical contact material that resists material transfer.

[0061] Testing showed that the thickness of each layer of the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer prepared in this embodiment met the requirements.

[0062] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A material transfer-resistant AgNi / AgSnO2 heterolayered electrical contact material, characterized in that, The electrical contact material is a heterogeneous layered structure with alternating AgNi and AgSnO2 layers, with a total of 2 to 6 layers and a single layer thickness of 100 μm to 400 μm. The electrical contact material is connected to the substrate through the AgNi layer.

2. The AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer according to claim 1, characterized in that, The AgNi layer is composed of the following components by mass percentage: Ni 8%~20%, balance Ag; the AgSnO2 layer is composed of the following components by mass percentage: SnO2 8%~20%, balance Ag; the electrical contact material is composed of the following components by mass percentage: SnO2 4%~16%, Ni 4%~16%, balance Ag.

3. A method for preparing the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer as described in claim 1 or 2, characterized in that, The method includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate, as well as the thickness and composition of each layer of the electrical contact material, and combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder and SnO2 powder for each layer according to the mass calculated in Step 1, and obtain the raw material powder for each layer. Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then heat and mechanically stir until the ethanol evaporates, and finally grind it to obtain the composite powder of each layer. Step 4: Anneal the composite powder obtained in Step 3 for each layer, and then grind it to obtain annealed powder for each layer. Step 5: Load the first layer of annealed powder from each layer of annealed powder obtained in Step 4 into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Then load the second layer of annealed powder into the mold, then put in the upper pressure head and apply vibration to the entire mold before removing the upper pressure head. Repeat the above process until each layer of powder is loaded into the mold to obtain a mold with annealed powder. Step 6: Pre-press the mold containing annealed powder obtained in Step 5, and then demold it to obtain a pressed blank; Step 7: The pressed blank obtained in Step 6 is sintered for the first time under inert gas protection to obtain a sintered block; Step 8: Press and densify the sintered block obtained in Step 7, then demold it to obtain a dense block. Step 9: The dense bulk material obtained in Step 8 is sintered a second time under inert gas protection to obtain AgNi / AgSnO2 heterolayer electrical contact material resistant to material transfer.

4. The method according to claim 3, characterized in that, In step two, the Ag powder is electrical silver powder with an average particle size of 5μm to 72μm, and the Ni powder and SnO2 powder have an average particle size of 0.2μm to 5μm. The mass purity of the Ag powder, Ni powder and SnO2 powder is not less than 99.5%. In step four, the annealing temperature is 500℃ to 810℃ and the time is 0.5h to 2h.

5. The method according to claim 3, characterized in that, The pressure for pre-compression molding in step six is ​​50MPa~300MPa; the pressure for compression molding in step eight is 800MPa~1000MPa.

6. The method according to claim 3, characterized in that, The heating rate for the first sintering in step seven is 5℃ / min~30℃ / min, the temperature is 700℃~900℃, and the time is 2h~4h; the heating rate for the second sintering in step nine is 5℃ / min~30℃ / min, the temperature is 600℃~700℃, and the time is 1h~2h.

7. A method for preparing the AgNi / AgSnO2 heterolayered electrical contact material resistant to material transfer as described in claim 1 or 2, characterized in that, The method includes the following steps: Step 1: Based on the area of ​​the electrical contact material required for the substrate and the thickness and composition of each layer of electrical contact material before and after rolling, combined with the density of the AgNi layer and the AgSnO2 layer, calculate the mass of Ag powder, Ni powder and SnO2 powder required for each layer. Step 2: Weigh out the required Ag powder, Ni powder and SnO2 powder for each layer according to the mass calculated in Step 1, and obtain the raw material powder for each layer. Step 3: Add ethanol to the raw material powder of each layer obtained in Step 2, then disperse it evenly by ultrasonication, then centrifuge and dry it, and finally grind it to obtain the composite powder of each layer. Step 4: Ball mill the composite powder obtained in Step 3, then dry and grind it to obtain ball-milled powder for each layer. Step 5: Load the first layer of ball mill powder obtained in each layer of ball mill powder in Step 4 into the mold, then put in the upper pressure head and apply vibration to the entire mold, then remove the upper pressure head. Then load the second layer of ball mill powder into the mold, then put in the upper pressure head and apply vibration to the entire mold, then remove the upper pressure head. Repeat the above process until each layer of ball mill powder is loaded into the mold, and obtain a mold with ball mill powder. Step 6: Pre-press the mold containing the ball milled powder obtained in Step 5, and then demold it to obtain the pressed blank; Step 7: The pressed blank obtained in Step 6 is sintered for the first time under inert gas protection to obtain a sintered block; Step 8: Perform the first pressure densification deformation on the sintered block obtained in step 7, and then demold to obtain a block with a regular shape; Step 9: The regularly shaped block obtained in Step 8 is sintered a second time under an inert gas protection to obtain sintered block material; Step 10: Perform a second pressure densification deformation on the sintered block material obtained in step 9, and then demold it to obtain a block material with a regular shape; Step 11: The regularly shaped blocks obtained in Step 10 are sintered for the third time under an inert gas protection to obtain sintered blocks; Step 12: Roll the sintered block material obtained in step 11 to obtain AgNi / AgSnO2 heterolayer electrical contact material that resists material transfer.

8. The method according to claim 7, characterized in that, In step 2, the Ag powder is electrical silver powder with an average particle size of 5μm to 72μm, and the Ni powder and SnO2 powder have an average particle size of 0.2μm to 5μm. The mass purity of the Ag powder, Ni powder, and SnO2 powder is not less than 99.5%. In step 4, the mass ratio of grinding balls, composite powder in each layer, and ethanol in the ball mill is 2 to 4:1:

1. The ball milling time is 1 to 6 hours, and the rotation speed is 200 to 300 rpm. The ball mill uses a stainless steel tank and stainless steel grinding balls. The stainless steel grinding balls are stainless steel grinding balls with a mass ratio of 1:1:1 and diameters of 3mm to 4mm, 4mm to 6mm, and 6mm to 8mm. The filling degree of the stainless steel tank does not exceed 20%.

9. The method according to claim 7, characterized in that, The pressure for pre-compression forming in step 6 is 100MPa~200MPa, the pressure for the first pressure densification deformation in step 8 is 300MPa~500MPa, and the pressure for the second pressure densification deformation in step 10 is 800MPa~1000MPa. In step 12, the deformation amount of a single pass of rolling does not exceed 5%. After the total deformation amount reaches 30%, annealing is performed at a temperature of 800℃~900℃ for 1h~2h. Rolling deformation continues until the required thickness is achieved.

10. The method according to claim 7, characterized in that, The heating rate for the first sintering in step 7 is 5℃ / min~10℃ / min, the temperature is 800℃~900℃, and the time is 1h~4h; the heating rate for the second sintering in step 9 is 5℃ / min~10℃ / min, the temperature is 800℃~900℃, and the time is 1h~4h; the heating rate for the third sintering in step 11 is 5℃ / min~10℃ / min, the temperature is 800℃~900℃, and the time is 1h~4h.

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