Silver-based conductive ceramic sheet-shaped contact material and preparation method thereof

Abstract

The invention discloses a silver-based conductive ceramic sheet-shaped contact material and a preparation method thereof, and belongs to the technical field of silver-based contact materials. The preparation method of the silver-based conductive ceramic flaky contact material comprises the following steps: carrying out chemical codeposition reaction on composite slurry obtained by carrying out high-energy ball milling on a specially prepared solid solution ITO and a solid solution ATO according to the mass ratio of (10: 1)-(1: 10), silver nitrate and sodium hydroxide to obtain composite powder with a uniformly dispersed reinforced phase and a core-shell structure; and the obtained composite powder and pure silver powder are formed after being laid in a mold, and then sintering, re-pressing and post-processing are conducted. The contact material prepared by the method provided by the invention has longer electrical life.

Description

Technical Field

[0001] This invention belongs to the technical field of silver-based contact materials, specifically relating to a silver-based conductive ceramic sheet contact material and its preparation method. Background Technology

[0002] Silver-based electrical contact materials are renowned for their excellent electrical and thermal conductivity. Silver-tin oxide (AgSnO2) electrical contact materials, composed of a silver matrix (Ag) and tin oxide (SnO2), have become the best alternative to toxic silver-cadmium oxide electrical contacts due to their superior wear resistance, resistance to welding, resistance to arc erosion, conductivity, and environmental friendliness. However, SnO2 itself has drawbacks such as high contact resistance, poor wettability between SnO2 particles and Ag, and the tendency for SnO2 particles to aggregate under arc conditions. These defects lead to unstable contact resistance in AgSnO2 contact materials, making them prone to temperature rises due to contact welding, which severely damages their electrical life.

[0003] To address the aforementioned problems, existing technologies improve the electrical properties of electrical contact materials by adding metal oxides (MeO, where Me represents Bi, In, Sb, etc.) or conductive ceramics to the silver matrix. For example:

[0004] The invention patent with publication number CN106119592A discloses a silver-based conductive ceramic electrical contact alloy, which uses a Ba-containing... 2+ Pb 2+ Rare earth element oxalate powder was calcined to obtain rare earth element-doped BaPbO3 black powder. This rare earth element-doped BaPbO3 black powder was then mixed with silver powder and prepared through a pressing-sintering-extrusion process. This invention improves the conductivity of barium leadate by effectively doping with rare earth elements, reducing the resistance of the contact alloy body. Simultaneously, the second phase of barium leadate exhibits excellent conductivity, solving the problems of high contact resistance, temperature rise, and high oxide loss during arc erosion caused by poor conductivity of the second phase in traditional silver-based electrical contact materials. This improves the arc erosion resistance of silver-based conductive ceramic electrical contact alloys.

[0005] Liu Xiao et al. (Influence of ITO Reinforcement on Microstructure and Properties of AgSnO2 Electrical Contact Materials, Liu Xiao et al., Electrical Materials, No.4, pp.21-24, 2024.) proposed using a new conductive oxide ITO powder (indium tin oxide, typically composed of 90% In2O3 and 10% SnO2, with a body-centered cubic In2O3 main crystal structure and tetravalent Sn...). 4+ Replace trivalent In 3+A novel high-oxide electrical contact material, AgSnO2(10)ITO(5), was prepared by replacing In2O3 with a stable solid solution (by forming an alloy powder pre-oxidation method) and compared with AgSnO2(10)In2O3(5) with the same oxide content. The results showed that the electrical lifetime of AgSnO2(10)ITO(5) was increased by 30% compared with that of AgSnO2(10)ITO(5), reaching 60,000 cycles.

[0006] This application aims to provide a silver oxide tin contact material with a longer electrical life. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a silver-based conductive ceramic contact material with longer electrical life and lower cost, and a method for preparing the same.

[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0009] A method for preparing a silver-based conductive ceramic contact material includes the following steps:

[0010] 1) Preparation of ITO solid solutions with high In content and low Sn content:

[0011] In2O3 powder and SnO2 powder were weighed at a mass ratio of 95:5 and placed in a high-energy ball mill. Grinding balls and water were added for ball milling. After ball milling, the material was removed, dried, and then dispersed to separate the grinding balls, thus obtaining powder I. The obtained powder I was calcined at high temperature and pulverized to obtain solid solution ITO.

[0012] 2) Preparation of ATO solid solutions with high Sn and low Sb:

[0013] Sb2O3 powder and SnO2 powder were weighed at a mass ratio of 5:95 and placed in a high-energy ball mill. Grinding balls and water were added for ball milling. After ball milling, the material was removed, dried, and then dispersed to separate the grinding balls, thus obtaining powder II. The obtained powder II was calcined at high temperature and pulverized to obtain solid solution ATO.

[0014] 3) Weigh the solid solution ITO and solid solution ATO at a mass ratio of 10:1 to 1:10 and place them in a high-energy ball mill. Add grinding balls and water for ball milling. After ball milling, remove the material and separate the grinding balls to obtain a composite slurry.

[0015] 4) Add silver nitrate and sodium hydroxide to the composite slurry to carry out a chemical co-deposition reaction. After the reaction is completed, filter the mixture, wash the residue with water and dry it to obtain the composite powder.

[0016] 5) In the mold, first lay a layer of pure Ag powder, then lay a layer of composite powder on top of the pure Ag powder, and then form it to obtain the contact blank;

[0017] 6) The obtained contact blank is subjected to sintering, repressing and post-processing to obtain the silver-based conductive ceramic contact material.

[0018] In step 1), zirconia balls are typically used as grinding balls, with a ball-to-material ratio usually between 3:1 and 10:1. During ball milling, the milling speed is 100-200 r / min, and the milling time is 30-50 h. The material after ball milling includes a slurry of In2O3 powder, SnO2 powder, and water, as well as the grinding balls. The dried material is preferably dispersed by ball milling and then sieved to separate the grinding balls.

[0019] In step 2), zirconia balls are typically used as grinding balls, with a ball-to-material ratio usually between 1:1 and 5:1. During ball milling, the milling speed is 200-400 r / min, and the milling time is 10-20 h. The material after ball milling includes a slurry of Sb₂O₃ powder, SnO₂ powder, and water, as well as grinding balls. The dried material is preferably dispersed by ball milling and then sieved to separate the grinding balls.

[0020] Furthermore, in step 1), the high-temperature calcination temperature is 1500~1800℃, and the calcination time is 4~6h.

[0021] Furthermore, in step 2), the high-temperature calcination temperature is 800~1000℃, and the calcination time is 2~4h.

[0022] In step 3), the ball milling speed is 100~400 r / min and the ball milling time is 1~10 h.

[0023] In step 4), the amount of silver nitrate is calculated based on the material ratio of the target contact to be prepared, and the amount of sodium hydroxide is calculated based on the determined amount of silver nitrate. The silver nitrate can be added in solid or aqueous solution form. When silver nitrate is added in solid form, it is preferable to first dilute the composite slurry obtained in step 3) with water before adding the silver nitrate to facilitate its dissolution and the full progress of subsequent reactions. When silver nitrate is added in aqueous solution form, it is first prepared into a 20-40 wt% silver nitrate aqueous solution with water before addition. The sodium hydroxide is added in aqueous solution form, typically by preparing a 10-30 wt% sodium hydroxide aqueous solution with water.

[0024] In step 4), the retentate is washed with water until pH < 10, more preferably until pH < 8.

[0025] Preferably, the composite powder obtained in step 4) is granulated before step 5). This is more conducive to improving the flowability of the composite powder, increasing the loose density of the powder after granulation, reducing the "bridging" phenomenon during powder loading, and is especially beneficial to the uniformity of mold cavity filling in the automatic pressing process. The granulation is usually carried out in a swing granulator.

[0026] In step 5), the thickness of the pure Ag powder and the composite powder is determined as needed. Typically, the thickness of the pure Ag powder is 150-200 μm, and the thickness of the composite powder is 1.5-2.5 mm. The molding pressure during molding is preferably 200-500 MPa.

[0027] In step 6), the sintering, re-pressing, and post-processing steps are all the same as existing conventional operations, specifically:

[0028] The sintering process adopts a segmented sintering process, specifically: holding at 400~500℃ for 0.5~3h, then raising the temperature to 600~700℃ and holding for 1~3h, and then raising the temperature to 800~950℃ and holding for 2~6h.

[0029] The repressurization pressure is 500~1000MPa.

[0030] Post-processing steps include routine post-processing operations such as deburring, cleaning, and drying.

[0031] The drying involved in the method described in this invention usually refers to drying in an oven at a temperature of 50~300℃.

[0032] The present invention also includes silver-based conductive ceramic contact materials prepared by the above method.

[0033] Compared with the prior art, the present invention is characterized by:

[0034] 1. Synergistic regulation of high-energy ball milling and high-temperature calcination: SnO2 and In2O3 are mixed at a certain mass ratio, and the particles are crushed and the grain boundaries are refined by high-energy ball milling to improve the reactivity of the powder. Then, the activated SnO2 and In2O3 are calcined under high temperature to form a solid solution ITO, which increases the carrier concentration and reduces the resistivity from the insulating level (10²Ω·cm) to the semiconductor level (10). -4 (Ω·cm), achieving a qualitative change in the material's conductivity. Similarly, highly conductive solid solutions of ATO are obtained.

[0035] 2. High-energy ball milling composites are performed on indium tin oxide (ITO) powder with a stable solid solution structure and antimony-doped tin oxide (ATO) powder in a specific ratio. This process essentially utilizes mechanochemical effects to achieve "nanoscale uniform dispersion - interface activation modification - synergistic performance optimization," aiming to overcome the performance limitations of single solid solutions (such as high cost and poor temperature resistance of ITO; insufficient conductivity of ATO), thereby expanding its applicability in high-end applications (such as composite modification of electrical switch contacts). Through high-energy ball milling composites, the macroscopic physical mixing boundary of the two solid solution powders can be broken, achieving uniform dispersion at the nanoscale and effectively suppressing the effects of density differences (ITO density is 7.17 g·cm³). -3 The density of ATO is 6.95 g·cm³. -3 This leads to delamination and segregation during use. For Ag-MeO switch contact materials, uniform dispersion of the composite powder in the silver matrix can avoid arc-concentrated erosion caused by uneven local conductivity / thermal conduction, thereby improving contact life. Furthermore, the instantaneous high temperature and mechanical stress generated during high-energy ball milling promote lattice distortion-induced atomic interdiffusion on the surfaces of ITO and ATO particles: In in ITO... 3+ Sn 4+ Sn in ATO 4+ Sb 3+ Interdiffusion occurs at the interface, forming an "ITO-ATO composite solid solution transition phase." This interfacial transition layer eliminates the lattice mismatch between the two materials (ITO has a cubic lattice, and ATO has a tetragonal lattice), reduces the interfacial energy, and enhances the interfacial bonding strength. The synergistic effect of mechanically induced lattice distortion (dislocations, oxygen vacancies) and ion doping achieves a balanced optimization of conductivity and stability: the resistivity of the composite powder can be as low as 5 × 10⁻⁶. -4 ~1×10 -3 The temperature resistance is close to that of pure ITO (Ω·cm), while its temperature resistance and weather resistance are significantly better than those of ITO alone. The oxygen vacancies introduced by high-energy ball milling serve as carrier transport channels, compensating for the insufficient carrier concentration in a single ATO solid solution. The interfacial transition phase provides a "carrier bridge," reducing the contact resistance between ITO and ATO particles and improving overall conductivity. The rutile structure of SnO2 in ATO (withstanding temperatures up to 1630°C) effectively supports the cubic structure of ITO, suppressing ITO grain coarsening and oxygen vacancy loss at high temperatures; Sb... 3+ The introduction of [something] helps to suppress In [something] in ITO. 3+ The migration of ATO enhances the weather resistance of the composite system. Therefore, this composite powder is particularly suitable for mid-to-high-end electrical switch contacts, simultaneously achieving high conductivity (reducing contact resistance) and excellent resistance to arc erosion (ATO's high-temperature stability inhibits the melting of the silver matrix).

[0036] 3. Core-shell structure constructed by chemical co-deposition: A silver layer is deposited in situ on the surface of solid solution particles using chemical co-deposition to form a core-shell structure. This core-shell structure can reduce the interfacial bonding energy and effectively reduce the interfacial resistance, thereby further reducing the resistivity of the material. At the same time, the silver layer prevents the conductive ceramic particles from directly contacting each other, solving the problem of nanomaterial agglomeration and ensuring the uniform dispersion of the reinforcing phase.

[0037] 4. Forming-Sintering Densification Control: High forming pressure is used to obtain a high-density green body, and then the sintering process allows the silver layer deposited in situ on the surface of the solid solution particles to promote the sintering densification process. The superplastic flow of the silver matrix fills the micro gaps, and finally a material with low porosity and high density is obtained.

[0038] 5. By adopting the above-mentioned core process optimization combination, the cost is low, and the resulting contact material has excellent physical and electrical properties, thus resolving the contradiction between arc resistance and cost control. Attached Figure Description

[0039] Figure 1 The metallographic structure of the contact material prepared in Example 1 of the present invention is shown as (AgATO(8)ITO(4) 200×).

[0040] Figure 2 The metallographic structure of the contact material prepared in Comparative Example 1-1 of the present invention is shown in the figure (AgATO(8)ITO(4) 200×).

[0041] Figure 3 The metallographic structure of the contact material prepared in Comparative Examples 1-2 of this invention is shown in the figure (AgSnO2(8)ITO(4) 200×).

[0042] Figure 4 The metallographic structure of the contact material prepared in Comparative Examples 1-3 of this invention is shown in the figure (AgATO(8)In2O3(4) 200×).

[0043] Figure 5 The metallographic structure of the contact materials prepared in Comparative Examples 1-4 of this invention is shown in the figure (AgSnO2(8)In2O3(4) 200×). Detailed Implementation

[0044] To better explain the technical solution of the present invention, the present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0045] The grinding balls described in the following embodiments are all zirconia balls.

[0046] Example 1: Preparation of AgATO(8)ITO(4) contacts (material chemical formula is AgSnO2(8)In2O3(4))

[0047] 1) Preparation of solid solution ITO:

[0048] In₂O₃ powder and SnO₂ powder were weighed at a mass ratio of 95:5 and placed in a high-energy ball mill. Grinding balls and water were added for ball milling, with a ball-to-material ratio of 3:1. The amount of water added was equal to the sum of the weights of the In₂O₃ powder and SnO₂ powder. The ball milling speed was 200 r / min, and the ball milling time was 40 h. After ball milling, the material was removed and placed in an oven to dry at 150 °C for 10 h. The dried material was then fed into a ball mill jar for ball milling and dispersing (ball milling speed was 100 r / min, and the ball milling time was 0.5 h). The grinding balls were separated to obtain powder I. Powder I was then calcined at 1600 °C for 4 h, and the resulting material was pulverized to obtain solid solution ITO (In₂O₃·SnO₂ composite oxide powder, i.e., ITO conductive ceramic powder).

[0049] 2) Preparation of solid solution ATO:

[0050] Sb₂O₃ powder and SnO₂ powder were weighed at a mass ratio of 5:95 and placed in a high-energy ball mill. Grinding balls and water were added for ball milling, with a ball-to-material ratio of 3:1. The amount of water added was equal to the sum of the weights of the Sb₂O₃ powder and SnO₂ powder. The ball milling speed was 200 r / min, and the ball milling time was 10 h. After ball milling, the material was removed and placed in an oven to dry at 150 °C for 10 h. The dried material was then fed into a ball mill jar for ball milling and dispersing (ball milling speed was 100 r / min, and the ball milling time was 0.5 h). The grinding balls were separated to obtain powder II. Powder II was then calcined at 800 °C for 2 h. The resulting material was pulverized to obtain solid solution ATO (SnO₂·Sb₂O₃ composite oxide powder, i.e., ATO conductive ceramic powder).

[0051] 3) Weigh 200g of ITO solid solution and 400g of ATO solid solution (the mass ratio of ITO solid solution to ATO solid solution is 1:2) and place them in a high-energy ball mill. Add grinding balls and water for ball milling. The ball-to-material ratio is 3:1. The amount of water added is the sum of the weights of ITO solid solution and ATO solid solution. The ball milling speed is 200r / min and the ball milling time is 2h. After ball milling, remove the material and sieve it to separate the grinding balls, obtaining a composite slurry. Add 2L of water to the obtained composite slurry for dilution to obtain a diluted composite slurry.

[0052] 4) Weigh out 6.93 kg of silver nitrate and 1.63 kg of sodium hydroxide, and prepare a 25 wt% sodium hydroxide aqueous solution with water for later use;

[0053] Then, add the weighed silver nitrate to the diluted composite slurry obtained in step 3), disperse it evenly by ultrasonication, and then add the prepared sodium hydroxide aqueous solution under stirring to carry out a co-deposition reaction. After the reaction is completed, filter it, wash the residue with water until pH < 8, and then place it in an oven to dry at 250℃ for 8 hours to obtain composite powder.

[0054] 5) The obtained composite powder is granulated using a vibrating granulator to obtain granulated composite powder;

[0055] 6) In the molding die (12mm×12mm, length×width), first lay a layer of pure Ag powder (0.3g), then lay a layer of granulated composite powder (2.56g) on ​​the pure Ag powder, and mold it under a pressure of 200MPa to obtain a sheet-like contact blank.

[0056] 7) The obtained contact blanks are placed in a sintering furnace for segmented sintering. The specific segmented sintering process is: 400℃×3h + 650℃×2h + 900℃×2h, to obtain contact ingots. The obtained contact ingots are then re-pressed under 800 MPa, and then tumbled to remove burrs using a double-cylinder tumbler. After cleaning and drying, finished sheets with dimensions of 12mm×12mm×2mm are obtained. The metallographic structure of the finished sheets obtained in this example is shown below. Figure 1 As shown.

[0057] Comparative Example 1-1: Preparation of AgATO(8)ITO(4) contacts

[0058] Unlike Example 1, the solid solution ITO in step 1) is replaced with commercially available ITO.

[0059] The metallographic structure of the finished sheet obtained in this example is as follows: Figure 2 As shown.

[0060] Comparative Examples 1-2

[0061] Unlike Example 1, only solid solution ITO was used as the reinforcing phase, that is, the amount of solid solution ATO in step 3) was 0 kg.

[0062] The metallographic structure of the finished sheet obtained in this example is as follows: Figure 3 As shown.

[0063] Comparative Examples 1-3

[0064] Unlike Example 1, only solid solution ATO was used as the reinforcing phase, that is, the amount of solid solution ITO in step 3) was 0 kg.

[0065] The metallographic structure of the finished sheet obtained in this example is as follows: Figure 4 As shown.

[0066] Comparative Examples 1-4

[0067] Unlike Example 1, in step 3), the solid solution ITO was replaced with commercially available In2O3, and the solid solution ATO was replaced with commercially available SnO2.

[0068] The metallographic structure of the finished sheet obtained in this example is as follows: Figure 5 As shown.

[0069] Example 2: Preparation of AgATO(8)ITO(4) contacts (material chemical formula is AgSnO2(8)In2O3(4))

[0070] Unlike Example 1, in step 4), the amounts of silver nitrate and sodium hydroxide weighed are 13.86 kg and 3.26 kg, respectively.

[0071] Example 3: Preparation of AgATO(8)ITO(4) contacts (material chemical formula is AgSnO2(8)In2O3(4))

[0072] Unlike Example 1, in step 5), a φ16mm molding die was used, the amount of pure Ag powder was 0.42g, and the amount of granulated composite powder was 3.43g.

[0073] Example 4: Preparation of AgATO(10)ITO(2) contacts (material chemical formula is AgSnO2(10)In2O3(2))

[0074] Unlike Example 1, in step 3), the amounts of solid solution ITO and solid solution ATO weighed are 0.1 kg and 0.5 kg, respectively, and the mass ratio of solid solution ITO to solid solution ATO is 1:5.

[0075] Example 5: Preparation of AgATO(2)ITO(10) contacts (material chemical formula is AgSnO2(2)In2O3(10))

[0076] Unlike Example 1, in step 3), the amounts of solid solution ITO and solid solution ATO weighed are 0.5 kg and 0.1 kg, respectively, and the mass ratio of solid solution ITO to solid solution ATO is 5:1.

[0077] Example 6: Preparation of AgATO(10)ITO(1) contacts (material chemical formula is AgSnO2(10)In2O3(1))

[0078] Unlike Example 1:

[0079] In step 1), when preparing the solid solution ITO, the ball-to-powder ratio is 8:1, and the ball milling time is 30 h; powder I is calcined at 1800 °C for 5 h.

[0080] In step 2), when preparing the solid solution ATO, the ball-to-powder ratio is 10:1 and the ball milling time is 20 h; powder II is calcined at 800 °C for 4 h.

[0081] In step 3), the amounts of solid solution ITO and solid solution ATO weighed are 1 kg and 10 kg respectively, and the mass ratio of solid solution ITO to solid solution ATO is 1:10.

[0082] In step 4), the weighed amounts of silver nitrate and sodium hydroxide are 7.004 kg and 1.648 kg, respectively;

[0083] In step 6), the amount of pure Ag powder used is 0.3g, and the amount of composite powder used on the pure Ag powder is 2.57g. The molding is carried out under a pressure of 500MPa.

[0084] In step 7), the specific segmented sintering process is as follows: 500℃×2h+600℃×3h+800℃×6h, and the resulting contact billet is subjected to re-pressing under 1000Mpa conditions.

[0085] Comparative Example 6: Preparation of AgATO(11)ITO(1) contacts (material chemical formula is AgSnO2(11)In2O3(1))

[0086] The difference from Example 6 is:

[0087] In step 3), the amounts of solid solution ITO and solid solution ATO are 50g and 550g respectively, and the mass ratio of solid solution ITO to solid solution ATO is 1:11.

[0088] In step 4), the amounts of silver nitrate and sodium hydroxide weighed are 6.93 kg and 1.63 kg, respectively.

[0089] Example 7: Preparation of AgATO(1)ITO(10) contacts (material chemical formula is AgSnO2(1)In2O3(10))

[0090] Unlike Example 1:

[0091] In step 1), when preparing the solid solution ITO, the ball-to-powder ratio is 10:1 and the ball milling time is 50 h; powder I is calcined at 1500 °C for 6 h.

[0092] In step 2), when preparing the solid solution ATO, the ball-to-material ratio is 5:1 and the ball milling time is 20 hours.

[0093] In step 3), the amounts of solid solution ITO and solid solution ATO are 10 kg and 1 kg respectively, and the mass ratio of solid solution ITO to solid solution ATO is 10:1.

[0094] In step 4), the weighed amounts of silver nitrate and sodium hydroxide are 7.004 kg and 1.648 kg, respectively;

[0095] In step 6), the amount of pure Ag powder used is 0.3g, and the amount of composite powder used on the pure Ag powder is 2.86g. The molding is carried out under a pressure of 300MPa.

[0096] In step 7), the specific segmented sintering process is: 400℃×1h+700℃×1h+950℃×2h.

[0097] Comparative Example 7: Preparation of AgATO(1)ITO(11) contacts (material chemical formula is AgSnO2(1)In2O3(11))

[0098] The difference from Example 7 is:

[0099] In step 3), the amounts of solid solution ITO and solid solution ATO weighed are 550g and 50g, respectively, and the mass ratio of solid solution ITO to solid solution ATO is 11:1.

[0100] In step 4), the amounts of silver nitrate and sodium hydroxide weighed are 6.93 kg and 1.63 kg, respectively.

[0101] Table 1 lists the physical and electrical performance test results of the contact materials prepared in the above embodiments and comparative examples. Among them, the electrical life was tested using AC4 electrical life test (conditions: 400 VAC, rated current Ie=95 A, test current I=6Ie=570 A, cosφ=0.35).

[0102] Table 1:

[0103]

[0104] As can be seen from Table 1, the contact material prepared by the method described in this invention has better physical and electrical properties. Although Comparative Example 7 also obtained good physical and electrical properties, it used a larger amount of ITO and had a higher cost.

Claims

1. A method for preparing a silver-based conductive ceramic sheet contact material, comprising the following steps: 1) Preparation of ITO solid solutions with high In content and low Sn content: In2O3 powder and SnO2 powder were weighed at a mass ratio of 95:5 and placed in a high-energy ball mill. Grinding balls and water were added for ball milling. After ball milling, the material was removed, dried, and then dispersed to separate the grinding balls, thus obtaining powder I. The obtained powder I was calcined at high temperature and pulverized to obtain solid solution ITO. 2) Preparation of ATO solid solutions with high Sn and low Sb: Sb2O3 powder and SnO2 powder were weighed at a mass ratio of 5:95 and placed in a high-energy ball mill. Grinding balls and water were added for ball milling. After ball milling, the material was removed, dried, and then dispersed to separate the grinding balls, thus obtaining powder II. The obtained powder II was calcined at high temperature and pulverized to obtain solid solution ATO. 3) Weigh the solid solution ITO and solid solution ATO at a mass ratio of 10:1 to 1:10 and place them in a high-energy ball mill. Add grinding balls and water for ball milling. After ball milling, remove the material and separate the grinding balls to obtain a composite slurry. 4) Add silver nitrate and sodium hydroxide to the composite slurry to carry out a chemical co-deposition reaction. After the reaction is completed, filter the mixture, wash the residue with water and dry it to obtain the composite powder. 5) In the mold, first lay a layer of pure Ag powder, then lay a layer of composite powder on top of the pure Ag powder, and then form it to obtain the contact blank; 6) The obtained contact blank is subjected to sintering, repressing and post-processing to obtain the silver-based conductive ceramic sheet contact material.

2. The preparation method according to claim 1, characterized in that, In step 1), the ball-to-material ratio is 3:1 to 10:1, the ball mill speed is 100 to 200 r / min, and the ball milling time is 30 to 50 h.

3. The preparation method according to claim 1, characterized in that, In step 2), the ball-to-material ratio is 1:1 to 5:1, the ball mill speed is 200 to 400 r / min, and the ball milling time is 10 to 20 h.

4. The preparation method according to claim 1, characterized in that, In step 1), the high-temperature calcination temperature is 1500~1800℃, and the calcination time is 4~6h; In step 2), the high-temperature calcination temperature is 800~1000℃, and the calcination time is 2~4h.

5. The preparation method according to claim 1, characterized in that, In step 4), the silver nitrate is added in the form of a solid or an aqueous solution, and the sodium hydroxide is added in the form of an aqueous solution.

6. The preparation method according to claim 1, characterized in that, In step 4), the retentate is washed with water until pH < 10.

7. The preparation method according to claim 1, characterized in that, In step 5), the molding pressure is 200~500MPa.

8. The preparation method according to claim 1, characterized in that, In step 6), the sintering adopts a segmented sintering process, specifically: holding at 400~500℃ for 0.5~3h, then raising the temperature to 600~700℃ and holding for 1~3h, and then raising the temperature to 800~950℃ and holding for 2~6h.

9. The preparation method according to claim 1, characterized in that, In step 6), the repressurization pressure is 500~1000MPa.

10. The silver-based conductive ceramic sheet contact material prepared by the method according to any one of claims 1 to 9.

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