A novel multi-component silver-based contact material and its preparation method

Abstract

This invention discloses a novel multi-component silver-based contact material and its preparation method. The borides in the material possess both metallic and covalent bonds, exhibiting dual characteristics of ceramics and metals. Boride ceramics possess excellent comprehensive properties such as high hardness, high modulus, good thermal and electrical conductivity, and high chemical stability, thus becoming an ideal reinforcing phase for silver-based contact materials. The novel multi-component silver-based contact prepared according to the above proportions exhibits excellent arc-quenching performance, resistance to arc erosion, and low material transfer and mass loss. The main role of ZrB2 in the arc erosion process lies in its easily decomposable properties, which enhance the material's arc-quenching ability. Furthermore, boron is oxidized to B2O3 in air, providing a certain slag removal capability. Simultaneously, the oxygen generated by the decomposition of ZrO2 under arc action also has an arc-quenching effect, and Zr and Ag can form a solid solution, reducing splashing losses.

Description

Technical Field

[0001] This invention relates to the field of silver-based electrical contact technology, and in particular to a novel multi-component silver-based contact material and its preparation method. Background Technology

[0002] As core components of switching devices such as contactors, circuit breakers, relays, instruments, current limiting switches, motor protectors, micro switches, residual current devices, and automotive electrical systems, electrical contacts are primarily responsible for connecting and disconnecting circuits and load currents. Their performance directly affects the reliability, stability, and service life of electrical systems. Therefore, electrical contact materials are required to possess excellent electrical and thermal conductivity, superior breaking capacity, resistance to welding, resistance to electrical abrasion, low and stable contact resistance, good oxidation resistance, corrosion resistance, chemical stability, mechanical properties, and machinability.

[0003] Traditional AgCdO contact materials exhibit good resistance to arc erosion, excellent anti-welding properties, and low and stable contact resistance. However, the widespread application of cadmium is limited by the harmful effects of cadmium toxicity on human health and the environment. Although AgSnO2 contact materials have comparable performance to AgCdO contact materials, the poor wettability between Ag and SnO2 during service can easily lead to two-phase separation. This results in the aggregation of non-conductive SnO2 ceramic particles on the contact surface, causing increased contact resistance and surface temperature, severely affecting the stability and service life of electrical appliances.

[0004] With the increasing demands for miniaturization, high power, long lifespan, and reliability in switching devices, increasingly stringent requirements are being placed on the performance of contact materials. Therefore, developing a silver-based contact material with excellent overall performance has significant engineering implications and practical value. Summary of the Invention

[0005] The purpose of this invention is to provide a novel multi-component silver-based contact material and its preparation method, which enables the contact to have excellent resistance to arc erosion and excellent electrical properties such as resistance to welding.

[0006] To address the aforementioned technical problems, this invention provides a novel multi-component silver-based contact material, comprising, by mass percentage:

[0007] Ag: 80.0~95.0wt.%;

[0008] ZrB2: 2.0~5.0wt.%;

[0009] ZrO2: 3.0~15.0wt.%;

[0010] The sum of the mass percentages of the above components is 100%.

[0011] The aforementioned multi-component novel silver-based contact material comprises, by mass percentage:

[0012] Ag: 92.0 wt.%

[0013] ZrB2: 5.0 wt.%

[0014] ZrO2: 3.0 wt.%.

[0015] The aforementioned multi-component novel silver-based contact material comprises, by mass percentage:

[0016] Ag: 91.0 wt.%

[0017] ZrB2: 4.0 wt.%

[0018] ZrO2: 5.0 wt.%.

[0019] The aforementioned multi-component novel silver-based contact material comprises, by mass percentage:

[0020] Ag: 87.0 wt.%

[0021] ZrB2: 5.0 wt.%

[0022] ZrO2: 8.0 wt.%.

[0023] This invention also provides a method for preparing a novel multi-component silver-based contact, comprising the following steps:

[0024] Step (a): Prepare raw materials;

[0025] The raw materials used to prepare the novel multi-component silver-based contact were weighed and mixed. The raw materials, by mass percentage, included: Ag: 80.0–95.0 wt.%, ZrB2: 2.0–5.0 wt.%, and ZrO2: 3.0–15.0 wt.%.

[0026] Step (b): Ball milling and mixing;

[0027] The prepared raw materials are put into a mixing ball mill for ball milling and mixing. The speed of the mixing ball mill is set to 200-400 rpm and the mixing time is set to 4-8 hours.

[0028] Step (c): Three-dimensional vibration mixing;

[0029] The raw materials after ball milling are put into a three-dimensional vibration mixer for three-dimensional vibration mixing. The speed of the three-dimensional vibration mixer is set to 200-300 rpm and the mixing time is set to 2-4 hours.

[0030] Step (d): Cold isostatic pressing;

[0031] The uniformly mixed raw materials are placed into a cold isostatic press for pressing. The pressure is set to 100-400 MPa and the holding time is set to 3-10 min.

[0032] Step (e): Sintering;

[0033] The pressed raw material is placed in an atmosphere-protected furnace for sintering at a temperature of 700–800℃ for 1–2 hours.

[0034] Preferably, the ball milling media used in the ball milling and powder mixing step are zirconia balls; the ball-to-material ratio is 10:1 to 20:1.

[0035] Preferably, the ball-to-material ratio in the ball milling and mixing step is 10:1, 15:1, or 20:1.

[0036] Preferably, 0.3-0.5 wt.% anhydrous ethanol is added as a process control agent and 1.0-1.5 wt.% polyvinylpyrrolidone as a dispersant during the ball milling and mixing step.

[0037] Preferably, the ball milling media used in the three-dimensional vibration mixing step is ZrO2; the ball-to-material ratio is 5:1 to 10:1.

[0038] Preferably, the ball-to-powder ratio in the three-dimensional vibration mixing step is 7:1.

[0039] Compared with the prior art, the beneficial effects of the present invention are:

[0040] The novel multi-component silver-based contact exhibits excellent arc-quenching performance, resistance to arc erosion, and low material transfer and mass loss. The main role of ZrB2 in the arc erosion process lies in its easily decomposable properties, which enhance the material's arc-quenching ability. Furthermore, boron's oxidation to B2O3 in air provides some slag removal capability. Simultaneously, the oxygen generated by the decomposition of ZrO2 under arc conditions also contributes to arc quenching, and Zr and Ag can form a solid solution, reducing splashing losses. Attached Figure Description

[0041] Figure 1 This is a flowchart of a method for preparing a novel multi-component silver-based contact provided by the present invention. Detailed Implementation

[0042] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. The advantages and features of the present invention will become clearer from the following description and claims. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the present invention.

[0043] Example 1

[0044] This invention provides a novel multi-component silver-based contact material, comprising, by mass percentage:

[0045] Ag: 80.0~95.0wt.%;

[0046] ZrB2: 2.0~5.0wt.%;

[0047] ZrO2: 3.0~15.0wt.%;

[0048] The sum of the mass percentages of the above components is 100%.

[0049] Because borides possess both metallic and covalent bonds, exhibiting the duality of ceramics and metals, boride ceramics possess excellent comprehensive properties such as high hardness, high modulus, good thermal and electrical conductivity, and high chemical stability, making them ideal reinforcing phases for silver-based contact materials. The novel multi-component silver-based contacts prepared according to the above proportions exhibit excellent arc-quenching performance, resistance to arc erosion, and low material transfer and mass loss. The main role of ZrB2 in the arc erosion process lies in its easily decomposable nature, which enhances the material's arc-quenching ability. Furthermore, boron's oxidation to B2O3 in air provides a certain slag-removing capacity. Simultaneously, the oxygen generated by the decomposition of ZrO2 under arc action also contributes to arc quenching, and Zr and Ag can form a solid solution, reducing splashing losses.

[0050] Example 2

[0051] This invention provides a novel multi-component silver-based contact material, comprising, by mass percentage:

[0052] Ag: 92.0 wt.%

[0053] ZrB2: 5.0 wt.%

[0054] ZrO2: 3.0 wt.%.

[0055] Example 3

[0056] This invention provides a novel multi-component silver-based contact material, comprising, by mass percentage:

[0057] Ag: 91.0 wt.%

[0058] ZrB2: 4.0 wt.%

[0059] ZrO2: 5.0 wt.%.

[0060] Example 4

[0061] This invention provides a novel multi-component silver-based contact material, comprising, by mass percentage:

[0062] Ag: 87.0 wt.%

[0063] ZrB2: 5.0 wt.%

[0064] ZrO2: 8.0 wt.%.

[0065] Example 5

[0066] like Figure 1 As shown, the present invention also provides a method for preparing a novel multi-component silver-based contact, based on the materials with the composition of Example 1, including the following steps:

[0067] Step (a): Prepare raw materials;

[0068] The raw materials used to prepare the novel multi-component silver-based contact were weighed and mixed. The raw materials, by mass percentage, included: Ag: 80.0–95.0 wt.%, ZrB2: 2.0–5.0 wt.%, and ZrO2: 3.0–15.0 wt.%.

[0069] Step (b): Ball milling and mixing;

[0070] The prepared raw materials are put into a mixing ball mill for ball milling and mixing. The speed of the mixing ball mill is set to 200-400 rpm and the mixing time is set to 4-8 hours.

[0071] Step (c): Three-dimensional vibration mixing;

[0072] The raw materials after ball milling are put into a three-dimensional vibration mixer for three-dimensional vibration mixing. The speed of the three-dimensional vibration mixer is set to 200-300 rpm and the mixing time is set to 2-4 hours.

[0073] Step (d): Cold isostatic pressing;

[0074] The uniformly mixed raw materials are placed into a cold isostatic press for pressing. The pressure is set to 100-400 MPa and the holding time is set to 3-10 min.

[0075] Step (e): Sintering;

[0076] The pressed raw material is placed in an atmosphere-protected furnace for sintering at a temperature of 700–800℃ for 1–2 hours.

[0077] Specifically, the grinding media used in the ball milling mixing step are zirconia balls; the ball-to-material ratio is 10:1 to 20:1, with 10:1, 15:1, and 20:1 being the most effective. Material composition significantly affects the microstructure and properties of the material, and the preparation process is also a key factor influencing these properties. For powder metallurgy materials, the uniformity of the mixed powder significantly affects the material's performance; uneven component distribution significantly reduces the final material properties, with the mixing method primarily affecting the uniformity of component distribution. During ball milling, if the ball-to-material ratio is too high, friction and impact between grinding balls and between grinding balls and the inner wall of the grinding cylinder increase, reducing efficiency while increasing energy consumption and wear on the grinding balls and the grinding cylinder. However, if the ball-to-material ratio is too low, the increased material strengthens the buffering effect on the impact of the grinding balls, while the reduced number of grinding balls correspondingly reduces the number of impacts and frictions, failing to achieve the desired ball milling effect. Therefore, after multiple experiments, a ball-to-material ratio of 10:1 to 20:1 was selected as the optimal ball-to-material ratio for mixing raw materials in this invention, with the best results achieved when the ball-to-material ratios were 10:1, 15:1, and 20:1.

[0078] Specifically, higher rotational speeds during ball milling help improve efficiency, but higher speeds do not necessarily guarantee better efficiency. Ball milling efficiency depends on the size and quantity of grinding balls (i.e., ball size distribution and ball-to-material ratio), the material properties and the optimal combination of particle size, weight, rotational speed, and operating mode. Therefore, after numerous experiments, setting the rotational speed of the mixing ball mill between 200 and 400 rpm yielded the best results.

[0079] Specifically, during the ball milling process, the particles in the mill jar are continuously subjected to the impact, compression, and grinding action of the grinding balls, causing existing or newly formed cracks on their surfaces to expand continuously until they break or undergo plastic deformation. As the milling time increases, the particle size gradually becomes finer. However, with the refinement of the particles, the specific surface area and specific surface energy increase, increasing the tendency for powder agglomeration, which is detrimental to achieving uniformity of the components during the mixing process. Furthermore, excessively long milling times can easily introduce more impurities, which is not conducive to improving material properties. Therefore, after multiple experiments, setting the mixing time of the ball mill to 2–4 hours yielded the best results.

[0080] Specifically, during the ball milling and powder mixing process, 0.3–0.5 wt.% anhydrous ethanol is added as a process control agent and 1.0–1.5 wt.% polyvinylpyrrolidone as a dispersant. Anhydrous ethanol coats the particle surface during mixing, preventing agglomeration and sedimentation, thus improving powder dispersion. Polyvinylpyrrolidone can, to some extent, increase powder yield, improve powder dispersion, and reduce the introduction of impurities during mixing.

[0081] Specifically, the ball milling medium used in the three-dimensional vibration mixing process is ZrO2; the ball-to-material ratio is set to 5:1 to 10:1, with the best effect achieved at a ratio of 7:1. While ball milling has high mixing efficiency, the centrifugal force causes material segregation and agglomeration, preventing complete and uniform powder mixing. Furthermore, the particle size distribution is inconsistent and follows a normal distribution, resulting in poor particle size uniformity and powder homogeneity. Therefore, a three-dimensional vibration mixer is used after ball milling for further mixing. During three-dimensional vibration mixing, the mixing drum rotates in multiple directions in three-dimensional space, accelerating the flow and diffusion of materials during mixing and avoiding the material segregation and agglomeration caused by centrifugal force in ball milling. This invention combines the advantages of ball milling and three-dimensional vibration mixing, further employing three-dimensional vibration mixing (a secondary mixing process) after ball milling of the composite powder, achieving uniform dispersion of the ZrB2, ZrO2, and Ag composite powder.

[0082] The hardness of the prepared silver-based contacts can reach 80-95 Hv. The higher the content of ZrB2 and ZrO2, the higher the hardness. At the same time, the higher the content of ZrB2 and ZrO2, the better the resistance to arc erosion, the better the resistance to material transfer, and the smaller the mass loss. The conductivity of the silver-based contacts can reach 65-85% IACS. The higher the silver content, the higher the conductivity.

[0083] Example 6

[0084] like Figure 1 As shown, the present invention also provides a method for preparing a novel multi-component silver-based contact, based on the materials of the composition of Example 2, including the following steps:

[0085] Step (a): Prepare raw materials;

[0086] The raw materials used to prepare the novel multi-component silver-based contact were weighed and mixed. The raw materials, by mass percentage, included: Ag: 92.0 wt.%, ZrB2: 5.0 wt.%, ZrO2: 3.0 wt.%.

[0087] Step (b): Ball milling and mixing;

[0088] The prepared raw materials are put into a mixing ball mill for ball milling and mixing. The speed of the mixing ball mill is set to 200-400 rpm and the mixing time is set to 4-8 hours.

[0089] Step (c): Three-dimensional vibration mixing;

[0090] The raw materials after ball milling are put into a three-dimensional vibration mixer for three-dimensional vibration mixing. The speed of the three-dimensional vibration mixer is set to 200-300 rpm and the mixing time is set to 2-4 hours.

[0091] Step (d): Cold isostatic pressing;

[0092] The uniformly mixed raw materials are placed into a cold isostatic press for pressing. The pressure is set to 100-400 MPa and the holding time is set to 3-10 min.

[0093] Step (e): Sintering;

[0094] The pressed raw material is placed in an atmosphere-protected furnace for sintering at a temperature of 700–800℃ for 1–2 hours.

[0095] Specifically, the grinding media used in the ball milling mixing step are zirconia balls; the ball-to-material ratio is 10:1 to 20:1, with 10:1, 15:1, and 20:1 being the most effective. Material composition significantly affects the microstructure and properties of the material, and the preparation process is also a key factor influencing these properties. For powder metallurgy materials, the uniformity of the mixed powder significantly affects the material's performance; uneven component distribution significantly reduces the final material properties, with the mixing method primarily affecting the uniformity of component distribution. During ball milling, if the ball-to-material ratio is too high, friction and impact between grinding balls and between grinding balls and the inner wall of the grinding cylinder increase, reducing efficiency while increasing energy consumption and wear on the grinding balls and the grinding cylinder. However, if the ball-to-material ratio is too low, the increased material strengthens the buffering effect on the impact of the grinding balls, while the reduced number of grinding balls correspondingly reduces the number of impacts and frictions, failing to achieve the desired ball milling effect. Therefore, after multiple experiments, a ball-to-material ratio of 10:1 to 20:1 was selected as the optimal ball-to-material ratio for mixing raw materials in this invention, with the best results achieved when the ball-to-material ratios were 10:1, 15:1, and 20:1.

[0096] Specifically, higher rotational speeds during ball milling help improve efficiency, but higher speeds do not necessarily guarantee better efficiency. Ball milling efficiency depends on the size and quantity of grinding balls (i.e., ball size distribution and ball-to-material ratio), the material properties and the optimal combination of particle size, weight, rotational speed, and operating mode. Therefore, after numerous experiments, setting the rotational speed of the mixing ball mill between 200 and 400 rpm yielded the best results.

[0097] Specifically, during the ball milling process, the particles in the mill jar are continuously subjected to the impact, compression, and grinding action of the grinding balls, causing existing or newly formed cracks on their surfaces to expand continuously until they break or undergo plastic deformation. As the milling time increases, the particle size gradually becomes finer. However, with the refinement of the particles, the specific surface area and specific surface energy increase, increasing the tendency for powder agglomeration, which is detrimental to achieving uniformity of the components during the mixing process. Furthermore, excessively long milling times can easily introduce more impurities, which is not conducive to improving material properties. Therefore, after multiple experiments, setting the mixing time of the ball mill to 2–4 hours yielded the best results.

[0098] Specifically, during the ball milling and powder mixing process, 0.3–0.5 wt.% anhydrous ethanol is added as a process control agent and 1.0–1.5 wt.% polyvinylpyrrolidone as a dispersant. Anhydrous ethanol coats the particle surface during mixing, preventing agglomeration and sedimentation, thus improving powder dispersion. Polyvinylpyrrolidone can, to some extent, increase powder yield, improve powder dispersion, and reduce the introduction of impurities during mixing.

[0099] Specifically, the ball milling medium used in the three-dimensional vibration mixing process is ZrO2; the ball-to-material ratio is set to 5:1 to 10:1, with the best effect achieved at a ratio of 7:1. While ball milling has high mixing efficiency, the centrifugal force causes material segregation and agglomeration, preventing complete and uniform powder mixing. Furthermore, the particle size distribution is inconsistent and follows a normal distribution, resulting in poor particle size uniformity and powder homogeneity. Therefore, a three-dimensional vibration mixer is used after ball milling for further mixing. During three-dimensional vibration mixing, the mixing drum rotates in multiple directions in three-dimensional space, accelerating the flow and diffusion of materials during mixing and avoiding the material segregation and agglomeration caused by centrifugal force in ball milling. This invention combines the advantages of ball milling and three-dimensional vibration mixing, further employing three-dimensional vibration mixing (a secondary mixing process) after ball milling of the composite powder, achieving uniform dispersion of the ZrB2, ZrO2, and Ag composite powder.

[0100] The hardness of the prepared silver-based contacts can reach 80-95 Hv. The higher the content of ZrB2 and ZrO2, the higher the hardness. At the same time, the higher the content of ZrB2 and ZrO2, the better the resistance to arc erosion, the better the resistance to material transfer, and the smaller the mass loss. The conductivity of the silver-based contacts can reach 65-85% IACS. The higher the silver content, the higher the conductivity.

[0101] Example 7

[0102] like Figure 1 As shown, the present invention also provides a method for preparing a novel multi-component silver-based contact, based on the materials of the composition of Example 3, including the following steps:

[0103] Step (a): Prepare raw materials;

[0104] The raw materials used to prepare the novel multi-component silver-based contact were weighed and mixed. The raw materials, by mass percentage, comprised: Ag: 91.0 wt.%, ZrB2: 4.0 wt.%, ZrO2: 5.0 wt.%.

[0105] Step (b): Ball milling and mixing;

[0106] The prepared raw materials are put into a mixing ball mill for ball milling and mixing. The speed of the mixing ball mill is set to 200-400 rpm and the mixing time is set to 4-8 hours.

[0107] Step (c): Three-dimensional vibration mixing;

[0108] The raw materials after ball milling are put into a three-dimensional vibration mixer for three-dimensional vibration mixing. The speed of the three-dimensional vibration mixer is set to 200-300 rpm and the mixing time is set to 2-4 hours.

[0109] Step (d): Cold isostatic pressing;

[0110] The uniformly mixed raw materials are placed into a cold isostatic press for pressing. The pressure is set to 100-400 MPa and the holding time is set to 3-10 min.

[0111] Step (e): Sintering;

[0112] The pressed raw material is placed in an atmosphere-protected furnace for sintering at a temperature of 700–800℃ for 1–2 hours.

[0113] Specifically, the grinding media used in the ball milling mixing step are zirconia balls; the ball-to-material ratio is 10:1 to 20:1, with 10:1, 15:1, and 20:1 being the most effective. Material composition significantly affects the microstructure and properties of the material, and the preparation process is also a key factor influencing these properties. For powder metallurgy materials, the uniformity of the mixed powder significantly affects the material's performance; uneven component distribution significantly reduces the final material properties, with the mixing method primarily affecting the uniformity of component distribution. During ball milling, if the ball-to-material ratio is too high, friction and impact between grinding balls and between grinding balls and the inner wall of the grinding cylinder increase, reducing efficiency while increasing energy consumption and wear on the grinding balls and the grinding cylinder. However, if the ball-to-material ratio is too low, the increased material strengthens the buffering effect on the impact of the grinding balls, while the reduced number of grinding balls correspondingly reduces the number of impacts and frictions, failing to achieve the desired ball milling effect. Therefore, after multiple experiments, a ball-to-material ratio of 10:1 to 20:1 was selected as the optimal ball-to-material ratio for mixing raw materials in this invention, with the best results achieved when the ball-to-material ratios were 10:1, 15:1, and 20:1.

[0114] Specifically, higher rotational speeds during ball milling help improve efficiency, but higher speeds do not necessarily guarantee better efficiency. Ball milling efficiency depends on the size and quantity of grinding balls (i.e., ball size distribution and ball-to-material ratio), the material properties and the optimal combination of particle size, weight, rotational speed, and operating mode. Therefore, after numerous experiments, setting the rotational speed of the mixing ball mill between 200 and 400 rpm yielded the best results.

[0115] Specifically, during the ball milling process, the particles in the mill jar are continuously subjected to the impact, compression, and grinding action of the grinding balls, causing existing or newly formed cracks on their surfaces to expand continuously until they break or undergo plastic deformation. As the milling time increases, the particle size gradually becomes finer. However, with the refinement of the particles, the specific surface area and specific surface energy increase, increasing the tendency for powder agglomeration, which is detrimental to achieving uniformity of the components during the mixing process. Furthermore, excessively long milling times can easily introduce more impurities, which is not conducive to improving material properties. Therefore, after multiple experiments, setting the mixing time of the ball mill to 2–4 hours yielded the best results.

[0116] Specifically, during the ball milling and powder mixing process, 0.3–0.5 wt.% anhydrous ethanol is added as a process control agent and 1.0–1.5 wt.% polyvinylpyrrolidone as a dispersant. Anhydrous ethanol coats the particle surface during mixing, preventing agglomeration and sedimentation, thus improving powder dispersion. Polyvinylpyrrolidone can, to some extent, increase powder yield, improve powder dispersion, and reduce the introduction of impurities during mixing.

[0117] Specifically, the ball milling medium used in the three-dimensional vibration mixing process is ZrO2; the ball-to-material ratio is set to 5:1 to 10:1, with the best effect achieved at a ratio of 7:1. While ball milling has high mixing efficiency, the centrifugal force causes material segregation and agglomeration, preventing complete and uniform powder mixing. Furthermore, the particle size distribution is inconsistent and follows a normal distribution, resulting in poor particle size uniformity and powder homogeneity. Therefore, a three-dimensional vibration mixer is used after ball milling for further mixing. During three-dimensional vibration mixing, the mixing drum rotates in multiple directions in three-dimensional space, accelerating the flow and diffusion of materials during mixing and avoiding the material segregation and agglomeration caused by centrifugal force in ball milling. This invention combines the advantages of ball milling and three-dimensional vibration mixing, further employing three-dimensional vibration mixing (a secondary mixing process) after ball milling of the composite powder, achieving uniform dispersion of the ZrB2, ZrO2, and Ag composite powder.

[0118] The hardness of the prepared silver-based contacts can reach 80-95 Hv. The higher the content of ZrB2 and ZrO2, the higher the hardness. At the same time, the higher the content of ZrB2 and ZrO2, the better the resistance to arc erosion, the better the resistance to material transfer, and the smaller the mass loss. The conductivity of the silver-based contacts can reach 65-85% IACS. The higher the silver content, the higher the conductivity.

[0119] Example 8

[0120] like Figure 1As shown, the present invention also provides a method for preparing a novel multi-component silver-based contact, based on the materials of the composition of Example 4, comprising the following steps:

[0121] Step (a): Prepare raw materials;

[0122] The raw materials used to prepare the novel multi-component silver-based contact were weighed and mixed. The raw materials, by mass percentage, comprised: Ag: 87.0 wt.%, ZrB2: 5.0 wt.%, ZrO2: 8.0 wt.%.

[0123] Step (b): Ball milling and mixing;

[0124] The prepared raw materials are put into a mixing ball mill for ball milling and mixing. The speed of the mixing ball mill is set to 200-400 rpm and the mixing time is set to 4-8 hours.

[0125] Step (c): Three-dimensional vibration mixing;

[0126] The raw materials after ball milling are put into a three-dimensional vibration mixer for three-dimensional vibration mixing. The speed of the three-dimensional vibration mixer is set to 200-300 rpm and the mixing time is set to 2-4 hours.

[0127] Step (d): Cold isostatic pressing;

[0128] The uniformly mixed raw materials are placed into a cold isostatic press for pressing. The pressure is set to 100-400 MPa and the holding time is set to 3-10 min.

[0129] Step (e): Sintering;

[0130] The pressed raw material is placed in an atmosphere-protected furnace for sintering at a temperature of 700–800℃ for 1–2 hours.

[0131] Specifically, the grinding media used in the ball milling mixing step are zirconia balls; the ball-to-material ratio is 10:1 to 20:1, with 10:1, 15:1, and 20:1 being the most effective. Material composition significantly affects the microstructure and properties of the material, and the preparation process is also a key factor influencing these properties. For powder metallurgy materials, the uniformity of the mixed powder significantly affects the material's performance; uneven component distribution significantly reduces the final material properties, with the mixing method primarily affecting the uniformity of component distribution. During ball milling, if the ball-to-material ratio is too high, friction and impact between grinding balls and between grinding balls and the inner wall of the grinding cylinder increase, reducing efficiency while increasing energy consumption and wear on the grinding balls and the grinding cylinder. However, if the ball-to-material ratio is too low, the increased material strengthens the buffering effect on the impact of the grinding balls, while the reduced number of grinding balls correspondingly reduces the number of impacts and frictions, failing to achieve the desired ball milling effect. Therefore, after multiple experiments, a ball-to-material ratio of 10:1 to 20:1 was selected as the optimal ball-to-material ratio for mixing raw materials in this invention, with the best results achieved when the ball-to-material ratios were 10:1, 15:1, and 20:1.

[0132] Specifically, higher rotational speeds during ball milling help improve efficiency, but higher speeds do not necessarily guarantee better efficiency. Ball milling efficiency depends on the size and quantity of grinding balls (i.e., ball size distribution and ball-to-material ratio), the material properties and the optimal combination of particle size, weight, rotational speed, and operating mode. Therefore, after numerous experiments, setting the rotational speed of the mixing ball mill between 200 and 400 rpm yielded the best results.

[0133] Specifically, during the ball milling process, the particles in the mill jar are continuously subjected to the impact, compression, and grinding action of the grinding balls, causing existing or newly formed cracks on their surfaces to expand continuously until they break or undergo plastic deformation. As the milling time increases, the particle size gradually becomes finer. However, with the refinement of the particles, the specific surface area and specific surface energy increase, increasing the tendency for powder agglomeration, which is detrimental to achieving uniformity of the components during the mixing process. Furthermore, excessively long milling times can easily introduce more impurities, which is not conducive to improving material properties. Therefore, after multiple experiments, setting the mixing time of the ball mill to 2–4 hours yielded the best results.

[0134] Specifically, during the ball milling and powder mixing process, 0.3–0.5 wt.% anhydrous ethanol is added as a process control agent and 1.0–1.5 wt.% polyvinylpyrrolidone as a dispersant. Anhydrous ethanol coats the particle surface during mixing, preventing agglomeration and sedimentation, thus improving powder dispersion. Polyvinylpyrrolidone can, to some extent, increase powder yield, improve powder dispersion, and reduce the introduction of impurities during mixing.

[0135] Specifically, the ball milling medium used in the three-dimensional vibration mixing process is ZrO2; the ball-to-material ratio is set to 5:1 to 10:1, with the best effect achieved at a ratio of 7:1. While ball milling has high mixing efficiency, the centrifugal force causes material segregation and agglomeration, preventing complete and uniform powder mixing. Furthermore, the particle size distribution is inconsistent and follows a normal distribution, resulting in poor particle size uniformity and powder homogeneity. Therefore, a three-dimensional vibration mixer is used after ball milling for further mixing. During three-dimensional vibration mixing, the mixing drum rotates in multiple directions in three-dimensional space, accelerating the flow and diffusion of materials during mixing and avoiding the material segregation and agglomeration caused by centrifugal force in ball milling. This invention combines the advantages of ball milling and three-dimensional vibration mixing, further employing three-dimensional vibration mixing (a secondary mixing process) after ball milling of the composite powder, achieving uniform dispersion of the ZrB2, ZrO2, and Ag composite powder.

[0136] The hardness of the prepared silver-based contacts can reach 80-95 Hv. The higher the content of ZrB2 and ZrO2, the higher the hardness. At the same time, the higher the content of ZrB2 and ZrO2, the better the resistance to arc erosion, the better the resistance to material transfer, and the smaller the mass loss. The conductivity of the silver-based contacts can reach 65-85% IACS. The higher the silver content, the higher the conductivity.

[0137] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A method for preparing a novel multi-component silver-based contact, characterized in that, Includes the following steps: Step (a): Prepare raw materials; The raw materials used to prepare the novel multi-component silver-based contact were weighed and mixed. The raw materials, by mass percentage, included: Ag: 80.0–95.0 wt.%, ZrB2: 2.0–5.0 wt.%, and ZrO2: 3.0–15.0 wt.%. Step (b): Ball milling and mixing; The prepared raw materials are put into a mixing ball mill for ball milling and mixing. The speed of the mixing ball mill is set to 200-400 rpm and the mixing time is set to 4-8 hours. Add 0.3–0.5 wt.% anhydrous ethanol as a process control agent and 1.0–1.5 wt.% polyvinylpyrrolidone as a dispersant to the ball-milled powder mixture; Step (c): Three-dimensional vibration mixing; The raw materials after ball milling are put into a three-dimensional vibration mixer for three-dimensional vibration mixing. The speed of the three-dimensional vibration mixer is set to 200-300 rpm and the mixing time is set to 2-4 hours. The ball milling media used in the three-dimensional vibration mixing process is ZrO2; the ball-to-material ratio is 5:1 to 10:

1. Step (d): Cold isostatic pressing; The uniformly mixed raw materials are placed into a cold isostatic press for pressing. The pressure is set to 100-400 MPa and the holding time is set to 3-10 min. Step (e): Sintering; The pressed raw material is placed in an atmosphere-protected furnace for sintering at a temperature of 700–800℃ for 1–2 hours.

2. The method for preparing a novel multi-component silver-based contact as described in claim 1, characterized in that, The ball milling media used in the ball milling and powder mixing step are zirconia balls; the ball-to-material ratio is 10:1 to 20:

1.

3. The method for preparing a novel multi-component silver-based contact as described in claim 2, characterized in that, The ball-to-material ratio in the ball milling and mixing step is 10:1, 15:1, or 20:

1.

4. The method for preparing a novel multi-component silver-based contact as described in claim 1, characterized in that, The ball-to-powder ratio in the three-dimensional vibration mixing step is 7:

1.

5. The method for preparing a novel multi-component silver-based contact as described in claim 1, characterized in that, Among them, the multi-component novel silver-based contact material is expressed as a percentage by mass. include: Ag: 92.0 wt.% ZrB2: 5.0 wt.%; ZrO2: 3.0 wt.%.

6. The method for preparing a novel multi-component silver-based contact as described in claim 1, characterized in that, Among them, the multi-component novel silver-based contact material is expressed as a percentage by mass. include: Ag: 91.0 wt.% ZrB2: 4.0 wt.% ZrO2: 5.0 wt.%.

7. The method for preparing a novel multi-component silver-based contact as described in claim 1, characterized in that, Among them, the multi-component novel silver-based contact material is expressed as a percentage by mass. include: Ag: 87.0 wt.% ZrB2: 5.0 wt.% ZrO2: 8.0 wt.%.

Images