A resistive paste and a method of making the same

Abstract

This application relates to the field of resistive paste technology, and provides a resistive paste and its preparation method. The resistive paste comprises: 75-105 parts of conductive filler, 0.5-5 parts of high-temperature heat-resistant agent, 5-15 parts of glass powder, and 15-33 parts of organic carrier; the conductive filler contains nano-silver powder. The resistive paste provided in this application uses the added conductive filler as the core component to form a continuous and dense conductive network. The nano-silver powder significantly reduces the sintering temperature of the resistive paste, promotes sintering density, and enhances adhesion, thereby improving the stability and reliability of the resistor. The high-temperature heat-resistant agent has extremely high heat resistance, significantly improving the thermal stability, service life, and reliability of the resistor. The glass powder improves the compatibility between the paste and the substrate, effectively preventing cracking and delamination during sintering, and forms a denser protective layer, thereby inhibiting silver oxidation and improving the corrosion resistance of the resistor.

Description

Technical Field

[0001] This application belongs to the field of resistive paste technology, and in particular relates to a resistive paste and its preparation method. Background Technology

[0002] Surface mount resistors, as indispensable electronic components in modern electronic devices, perform crucial functions such as voltage division, current limiting, and signal processing. With the rapid advancements in electronic technology, surface mount resistors are gradually evolving towards higher precision, miniaturization, and higher reliability to meet the demands of increasingly complex electronic systems. Resistor paste, as one of the key materials in surface mount resistors, directly affects the electrical performance, durability, and consistency of the resistor, making it particularly important.

[0003] Ruthenium-based resistor pastes play a crucial role in the manufacture of chip resistors due to their excellent conductivity, superior chemical stability, and outstanding high-temperature resistance. Currently, the conductive component of ruthenium-based resistor pastes is primarily ruthenium dioxide (RuO2). However, they suffer from poor sintering performance at sintering temperatures below 850°C. During the fabrication of electronic components such as chip resistors, this can easily lead to incomplete sintering of the ruthenium-based resistor paste, resulting in an insufficiently continuous and dense conductive network. This affects the resistance stability, conductivity, and reliability of the resistor. Furthermore, existing ruthenium-based resistor pastes have poor thermal expansion coefficient matching with the substrate material, leading to insufficient adhesion between the paste and the substrate. This can cause problems such as detachment and cracking during use, thus deteriorating the lifespan and reliability of electronic components.

[0004] Therefore, there is an urgent need to develop a resistance paste with good sintering performance, stable resistance, and strong adhesion. Summary of the Invention

[0005] The purpose of this application is to provide a resistance paste and its preparation method, which aims to solve the problems of poor low-temperature sintering performance, unstable resistance value and weak adhesion of existing ruthenium-based resistance pastes.

[0006] To achieve the above-mentioned objectives, the technical solution adopted in this application is as follows:

[0007] In a first aspect, this application provides a resistive paste comprising the following components in parts by weight: 75-105 parts of conductive filler, 0.5-5 parts of high-temperature heat resistant agent, 5-15 parts of glass powder, and 15-33 parts of organic carrier.

[0008] Secondly, this application provides a method for preparing a resistive paste, comprising the following steps:

[0009] A high-temperature heat-resistant agent is added to an organic carrier and mixed to obtain a dispersion.

[0010] The conductive filler and glass powder are added to the dispersion liquid for dispersion treatment, and then subjected to three-roll ball milling and filtration to obtain the resistive slurry.

[0011] Compared with the prior art, this application has the following beneficial effects:

[0012] The resistor paste provided in the first aspect of this application incorporates conductive fillers as its core component, which form a continuous and dense conductive network. The nano-silver powder it contains significantly reduces the sintering temperature of the resistor paste, promotes sintering density, enhances adhesion, and improves conductivity, thereby improving the stability and reliability of the resistor. The added high-temperature heat-resistant agent has extremely high heat resistance, significantly improving the thermal stability, service life, and reliability of the resistor. The added glass powder improves the compatibility between the paste and the substrate, effectively preventing cracking and delamination during sintering, and forms a denser protective layer, thereby inhibiting silver oxidation and improving the corrosion resistance of the resistor. Therefore, the resistor paste of this application, through the synergistic effect of nano-silver powder, high-temperature heat-resistant agent, and glass powder, endows it with excellent sintering performance and stronger adhesion, resulting in stable resistance, high reliability, and long service life. Furthermore, this resistor paste is lead-free and complies with RoHS standards.

[0013] The method for preparing resistive paste provided in the second aspect of this application first uniformly disperses a high-temperature heat-resistant agent in an organic carrier, and then adds conductive filler and glass powder and disperses them evenly. This method can ensure that each component is fully and evenly dispersed, solving the problems of easy agglomeration of nanoparticles and difficulty in uniform dispersion of multiple components, thereby forming a uniform and stable resistive paste. Detailed Implementation

[0014] To make the technical problems, technical solutions, and beneficial effects of this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0015] The first aspect of this application provides a resistive paste comprising the following components in parts by weight: 75-105 parts of conductive filler, 0.5-5 parts of high-temperature heat resistant agent, 5-15 parts of glass powder, and 15-33 parts of organic carrier;

[0016] The conductive filler contains nano-silver powder.

[0017] The resistor paste provided in this application uses conductive filler as its core component to form a continuous and dense conductive network. The nano-silver powder it contains significantly reduces the sintering temperature of the resistor paste, promotes sintering density, enhances adhesion, and improves conductivity, thereby improving the stability and reliability of the resistor. The added high-temperature heat-resistant agent has extremely high heat resistance, significantly improving the thermal stability, service life, and reliability of the resistor. The added glass powder improves the compatibility between the paste and the substrate, effectively preventing cracking and delamination during sintering, and forms a denser protective layer, thereby inhibiting silver oxidation and improving the resistor's corrosion resistance. Therefore, the resistor paste of this application, through the synergistic effect of nano-silver powder, high-temperature heat-resistant agent, and glass powder, endows it with excellent sintering performance and stronger adhesion, resulting in stable resistance, high reliability, and long service life. Furthermore, this resistor paste is lead-free and complies with RoHS standards.

[0018] In this embodiment, the conductive filler comprises 65-85 parts of ruthenium dioxide powder and 10-20 parts of nano-silver powder. Due to its high surface activity and low melting point, nano-silver powder can act as a highly efficient sintering activator, preferentially melting during sintering to effectively bridge and weld ruthenium dioxide particles. This allows for sintering densification at temperatures below 850°C, forming a continuous and dense conductive network, thus solving the problems of poor low-temperature sintering properties and unstable resistance in ruthenium-based slurries. Furthermore, nano-silver powder can better penetrate into the matrix material during sintering, bonding more tightly with the matrix and enhancing the adhesion between the resistor and the matrix, thereby improving the reliability of the resistor. The addition range of nano-silver powder in this embodiment achieves optimal sintering promotion. If the content is too low, the promotion effect is insufficient; if the content is too high, excessive independent silver conductive pathways may form, altering the resistive characteristics of the slurry and leading to excessively high costs.

[0019] In the embodiments, the glass powder comprises a silver-cerium composite oxide, bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid, and zinc oxide in a mass ratio of (30~45):(25~40):(1~5):(1~5):(5~15):(1~5):(1~5). The silver oxide and cerium oxide in the silver-cerium composite oxide form a synergistic reaction, providing additional electron transport paths and reducing grain boundary resistance, thus improving electron transport efficiency. Simultaneously, the material exhibits good compatibility, and high-temperature sintering allows the glass phase to form a dense protective layer, inhibiting silver oxidation and enhancing corrosion resistance. Bismuth oxide and silicon dioxide constitute a low-melting glass phase, enabling low-temperature flow. Aluminum oxide and zinc oxide regulate thermal expansion and chemical durability. The gas generated by the decomposition of barium carbonate helps form a denser structure. Phosphoric acid enhances chemical bonding with the matrix. Therefore, under the synergistic effect of specific proportions of each component, it helps to wet the matrix and conductive filler during the sintering process, enhance the bonding force between the sintered body and the matrix, adjust the coefficient of thermal expansion, and form a more stable and dense sintered body, thereby significantly improving the adhesion, resistance stability and reliability of the sintered body.

[0020] In the examples, the particle size of ruthenium dioxide powder is 0.1~5μm.

[0021] In the embodiments, the particle size of the silver nanoparticles is 10~300nm. This particle size range has optimal sintering activity and surface effect, maximizing its low-temperature sintering promoting effect.

[0022] In the embodiments, the particle size of the glass powder is 0.5~3μm.

[0023] In the embodiments, the mass ratio of silver oxide to cerium oxide in the silver-cerium composite oxide is (85~95):(5~15).

[0024] In the embodiments, the fineness of the resistive slurry is ≤10μm and the viscosity is 50~300Pa·s.

[0025] In the embodiments, the high-temperature heat-resistant agent includes at least one of metal oxide solid solution powder, inorganic whiskers, and rare earth oxide powder. The metal oxide solid solution powder is formed by calcining Al2O3 powder, MgO powder, and ZrO2 powder in a mass ratio of (65~75):(15~25):(1~5). This metal oxide solid solution powder combines the advantages of Al2O3 powder, MgO powder, and ZrO2 powder, significantly improving the thermal stability of the resistivity of the sintered body, while also enhancing the hardness and toughness of the sintered body, making it wear-resistant and crack-resistant, and improving the service life and reliability of the resistivity. The inorganic whiskers are selected from Si3N4 whiskers with a diameter of 0.1~1µm, a length of 5~20µm, and an aspect ratio of 5~20. These Si3N4 whiskers play a role in reinforcing the framework during sintering, effectively suppressing excessive flow of the glass phase at high temperatures, and enhancing the mechanical strength and adhesion of the sintered body to the substrate. The rare earth oxide powder is selected from Y2O3 powder, which has good high-temperature stability and chemical inertness, and can stabilize the valence state of RuO2, thereby further stabilizing the resistivity of the sintered body.

[0026] In some embodiments, the high-temperature heat-resistant agent comprises metal oxide solid solution powder, inorganic whiskers, and rare earth oxide powder in a mass ratio of (3~6):(2~3):(0.5~1.5). These high-temperature heat-resistant agents can play a synergistic reinforcing role, which can significantly improve the thermal stability, adhesion, and service life of the sintered body.

[0027] In this embodiment, the high-temperature heat-resistant agent further includes an organic solvent comprising ethylene glycol, polyvinyl butyral, and diethylene glycol monobutyl ether in a mass ratio of (1-10):(1-5):(20-40). Ethylene glycol serves as a dispersion medium; polyvinyl butyral acts as a binder, forming a flexible coating layer on the surface of metal oxide solid solution powder, inorganic whiskers, or rare earth oxide powder, enhancing compatibility with the organic carrier; and diethylene glycol monobutyl ether, as a high-boiling-point solvent, ensures processing stability. Therefore, with a specific ratio of these three components, the thermal stability, service life, and reliability of the resistor can be significantly improved.

[0028] In the embodiments, the organic solvent accounts for 70-90% of the total mass of the high-temperature heat-resistant agent.

[0029] In the embodiments, the organic carrier comprises 5-10 parts ethyl cellulose, 3-6 parts ethylene glycol, 6-12 parts diethylene glycol monobutyl ether, and 1-5 parts terpineol. Ethyl cellulose, as the main binder and rheology modifier, provides good film-forming properties and printability; the compound solvent system of ethylene glycol and diethylene glycol monobutyl ether balances the dissolution and dispersion capabilities of each component, suitable evaporation rates, and process stability; terpineol, as a high-boiling-point solvent and leveling agent, prevents surface defects caused by excessive solvent evaporation during drying. Therefore, these organic carriers not only effectively disperse and support functional solid particles but also decompose and volatilize smoothly and completely during sintering, avoiding residual carbon from affecting the sintered body.

[0030] The second aspect of this application provides a method for preparing the resistive paste as described above.

[0031] The method for preparing the resistive paste according to the embodiments of this application includes the following steps:

[0032] S1: The high-temperature heat-resistant agent is added to the organic carrier and mixed to obtain a dispersion;

[0033] S2: The conductive filler and glass powder are added to the dispersion liquid for dispersion treatment, and then subjected to three-roll ball milling and filtration to obtain the resistive slurry.

[0034] The method for preparing resistive slurry provided in this application embodiment first uniformly disperses a high-temperature heat-resistant agent in an organic carrier, and then adds conductive filler and glass powder and disperses them evenly. This ensures that each component is fully and evenly dispersed, solves the problem of easy agglomeration of nanoparticles and difficulty in uniform dispersion of multiple components, thereby forming a uniform and stable resistive slurry.

[0035] The specific components and contents of the conductive filler, high-temperature heat-resistant agent, glass powder and organic carrier in steps S1 to S2 above are the same as those of the conductive filler, high-temperature heat-resistant agent, glass powder and organic carrier contained in the resistive paste described in the embodiments of the above application, and will not be repeated here.

[0036] In the above-mentioned step S2, the step of adding conductive filler and glass powder to the dispersion liquid for dispersion treatment includes: adding conductive filler to the dispersion liquid, using an ultrasonic-assisted ball milling device to fully disperse the mixture, and then adding glass powder for full dispersion.

[0037] In this embodiment, the steps for preparing the glass powder include: mixing a composite oxide of silver and cerium, bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid, and zinc oxide, followed by melting, cooling, crushing, and sieving to obtain glass powder. The melting temperature is 1000–1200°C, and the melting time is 10–60 min. The particle size of the glass powder is 0.5–2.5 μm.

[0038] In the embodiments, the steps for preparing the silver-cerium composite oxide include: dissolving silver salt and cerium salt in a solvent, then co-precipitating them with a precipitant, followed by solid-liquid separation, purification, and drying to obtain a silver-cerium composite hydroxide; and calcining the silver-cerium composite hydroxide to obtain the silver-cerium composite oxide. The silver salt is selected from silver nitrate or silver chloride, the cerium salt is selected from cerium nitrate or cerium chloride, and the precipitant is selected from ammonia and / or sodium hydroxide. The coprecipitation reaction is carried out at a temperature of 50–65°C for 6–8 hours, and the pH of the reaction system is 8.5–9.5. The calcination treatment is carried out at a temperature of 500–700°C.

[0039] In the embodiments, the steps for preparing the high-temperature heat-resistant agent include: adding at least one of metal oxide solid solution powder, inorganic whiskers, and rare earth oxide powder to an organic solvent and mixing them to obtain the high-temperature heat-resistant agent.

[0040] The following description is based on specific embodiments.

[0041] Example 1

[0042] This embodiment provides a resistive paste and its preparation method.

[0043] The resistive paste comprises the following components in parts by weight: 75 parts ruthenium dioxide powder, 15 parts nano silver powder, 3 parts high-temperature heat resistant agent, 10 parts glass powder, and 25 parts organic carrier.

[0044] The average particle size of ruthenium dioxide powder is 2.5 μm, and the average particle size of silver nanoparticles is 120 nm.

[0045] The high-temperature heat-resistant agent is composed of metal oxide solid solution powder, Si3N4 whiskers (average diameter 0.5µm, average length 12µm, average aspect ratio 15), Y2O3 powder, and organic solvent in a mass ratio of 4.4:2.4:1.2:32. The metal oxide solid solution powder is formed by calcining Al2O3 powder, MgO powder, and ZrO2 powder in a mass ratio of 70:25:5. The organic solvent includes ethylene glycol, polyvinyl butyral, and diethylene glycol monobutyl ether in a mass ratio of 6:3:30.

[0046] The glass powder has an average particle size of 1.5 μm and is composed of a silver-cerium composite oxide, bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid, and zinc oxide in a mass ratio of 40:30:3:2:10:2:3; in the silver-cerium composite oxide, the mass ratio of silver oxide to cerium oxide is 90:10.

[0047] The organic carrier consists of 8 parts ethyl cellulose, 4 parts ethylene glycol, 9 parts diethylene glycol monobutyl ether, and 3 parts terpineol.

[0048] The method for preparing resistive paste includes the following steps:

[0049] (1) Preparation of glass powder: According to the mass ratio of silver oxide and cerium oxide of 90:10, weigh appropriate amounts of silver nitrate and cerium chloride and add them to pure water and stir evenly to form a mixed solution; add the mixed solution, sodium hydroxide solution and ammonia solution to the reaction vessel and mix them. Control the temperature of the reaction vessel to 60℃ and the pH value of the reaction system to 9. Perform co-precipitation reaction for 7h. After filtration, washing and drying, silver-cerium composite hydroxide is obtained; calcine the silver-cerium composite hydroxide at 600℃ for 4h to obtain silver-cerium composite oxide.

[0050] Weigh out appropriate amounts of silver-cerium composite oxide, bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid, and zinc oxide in a mass ratio of 40:30:3:2:10:2:3, mix them, then melt them at 1100℃ for 30 minutes, pour them into deionized water for water quenching, and then dry, crush, and sieve them to obtain glass powder.

[0051] (3) Preparation of high temperature heat resistant agent: Add metal oxide solid solution powder, Si3N4 whiskers and Y2O3 powder to a mixed organic solvent of ethylene glycol, polyvinyl butyral and diethylene glycol monobutyl ether, and mix to obtain high temperature heat resistant agent.

[0052] (4) Preparation of resistive slurry: Add high-temperature heat-resistant agent to organic carrier and stir evenly to obtain dispersion;

[0053] Ruthenium dioxide powder and nano silver powder are added to the dispersion liquid, and the mixture is fully dispersed using an ultrasonic-assisted ball mill. Then glass powder is added and fully dispersed. The mixture is then subjected to a three-roll ball milling process, grinding 12 times, and filtered to obtain a resistive slurry.

[0054] Example 2

[0055] This embodiment provides a resistive paste and its preparation method.

[0056] The difference between the resistive paste and Example 1 is that the glass powder does not contain a composite oxide of silver and cerium.

[0057] The difference between the preparation method of the resistive slurry and Example 1 is: (1) Preparation of glass powder: weigh appropriate amounts of bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid and zinc oxide in a mass ratio of 30:3:2:10:2:3 and mix them. Then melt them at 1100℃ for 30 minutes, pour them into deionized water for water quenching, and then dry, crush and sieve them to obtain glass powder.

[0058] Example 3

[0059] This embodiment provides a resistive paste and its preparation method.

[0060] The difference between the resistive paste and Example 1 is that the high-temperature heat resistant agent does not contain Si3N4 whiskers, but is composed of metal oxide solid solution powder, Y2O3 powder and organic solvent in a mass ratio of 1.7:0.3:8.

[0061] The difference between the preparation method of the resistive paste and Example 1 is: (3) Preparation of high temperature heat resistant agent: add metal oxide solid solution powder and Y2O3 powder to a mixed organic solvent of ethylene glycol, polyvinyl butyral and diethylene glycol monobutyl ether, and perform mixing treatment to obtain high temperature heat resistant agent.

[0062] Example 4

[0063] This embodiment provides a resistive paste and its preparation method.

[0064] The difference between the resistive paste and Example 1 is that the high-temperature heat resistant agent does not contain metal oxide solid solution powder, but is composed of Si3N4 whiskers (average diameter 0.5µm, average length 12µm, average aspect ratio 15), Y2O3 powder and organic solvent in a mass ratio of 1:1:8.

[0065] Example 5

[0066] This embodiment provides a resistive paste and its preparation method.

[0067] The difference between the resistive paste and Example 1 is that "metal oxide solid solution powder" is replaced by "metal oxide mixed powder formed by simply mixing Al2O3 powder, MgO powder and ZrO2 powder in a mass ratio of 70:25:5".

[0068] Comparative Example 1

[0069] This embodiment provides a resistive paste and its preparation method, which differs from Embodiment 1 in that it does not contain nano silver powder.

[0070] Comparative Example 2

[0071] This embodiment provides a resistive paste and its preparation method. The difference from Embodiment 1 is that the glass powder is ordinary glass powder formed by melting, water quenching, drying, crushing and sieving of PbO, B2O3, SiO2 and ZnO in a mass ratio of 50:25:15:10.

[0072] Comparative Example 3

[0073] This embodiment provides a resistive paste and its preparation method. The difference from Embodiment 1 is that the high-temperature heat resistant agent is Al2O3 powder with an average particle size of 3μm.

[0074] Relevant performance test analysis:

[0075] 1. The fineness of the resistive slurry provided in Examples 1-5 and Comparative Examples 1-3 was tested using the scraper fineness method.

[0076] 2. The viscosity of the resistive slurry provided in Examples 1-5 and Comparative Examples 1-3 was tested using a rotational viscometer.

[0077] 3. The resistive pastes provided in Examples 1-5 and Comparative Examples 1-3 were printed onto glass substrates to form 1mm × 1mm sheet resistance patterns, and then sintered in an air sintering furnace at 800℃ to form resistive bodies. The sheet resistance of the resistive body was tested using a four-probe tester; the temperature coefficient of resistance (TCR) of the resistive body was tested using a resistance measuring instrument; and the adhesion of the resistive body was tested using an adhesion tester.

[0078] The test results are shown in Table 1:

[0079] Table 1

[0080]

[0081] As can be seen from Table 1, the temperature coefficient of the resistive body prepared in Example 1 is smaller than that in Comparative Example 1, and the adhesion of the resistive body prepared in Example 1 is greater than that in Comparative Example 1. The main reason is that the nano silver powder added in this application example can help the slurry to sinter and densify at a lower temperature, forming a continuous and dense conductive network, thereby improving the adhesion and temperature stability of the resistive body.

[0082] The temperature coefficient of the resistive body prepared in Example 1 is less than that in Comparative Example 2, and the adhesion of the resistive body prepared in Example 1 is greater than that in Comparative Example 2. The main reason is that the glass powder with special components added in this application example can wet the matrix and conductive filler during sintering, enhance the bonding strength between the sintered body and the matrix, adjust the coefficient of thermal expansion, and thus greatly improve the adhesion and resistance stability of the resistive body.

[0083] The temperature coefficient of the resistive element prepared in Example 1 is less than that in Comparative Example 3, and the adhesion of the resistive element prepared in Example 1 is greater than that in Comparative Example 3. The main reason is that the embodiments of this application added a high-temperature heat-resistant agent with special components. The metal oxide solid solution powder with extremely high heat resistance temperature can improve the resistance stability of the resistive element; Si3N4 whiskers serve as a reinforcing skeleton to suppress excessive flow of the glass phase at high temperatures, thereby enhancing the bonding strength between the resistive element and the substrate; rare earth oxide powder can stabilize the valence state of RuO2, thereby further improving the resistance stability of the resistive element.

[0084] The temperature coefficient of the resistive body prepared in Example 1 is less than that in Example 5, and the adhesion of the resistive body prepared in Example 1 is greater than that in Example 5. The main reason is that the resistive body added in Example 5 is a mixed powder formed by simply mixing Al2O3 powder, MgO powder and ZrO2 powder. During sintering, they need to be sintered and densified independently, which requires a higher sintering temperature. Moreover, they have different shrinkage behaviors, which easily form pores at the interface, thereby affecting the bonding strength between the resistive body and the substrate and the stability of the resistance value.

[0085] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A resistive paste, characterized in that, It comprises the following components in parts by weight: 75-105 parts conductive filler, 0.5-5 parts high-temperature heat resistant agent, 5-15 parts glass powder, and 15-33 parts organic carrier; The conductive filler comprises 65-85 parts of ruthenium dioxide powder and 10-20 parts of nano silver powder; The glass powder comprises a silver-cerium composite oxide, bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid, and zinc oxide in a mass ratio of (30~45):(25~40):(1~5):(1~5):(5~15):(1~5):(1~5) (1~5); and in the silver-cerium composite oxide, the mass ratio of silver oxide to cerium oxide is (85~95):(5~15). The high-temperature heat-resistant agent comprises metal oxide solid solution powder, inorganic whiskers, and rare earth oxide powder in a mass ratio of (3~6):(2~3):(0.5~1.5); the metal oxide solid solution powder is formed by calcination of Al2O3 powder, MgO powder, and ZrO2 powder in a mass ratio of (65~75):(15~25):(1~5); the inorganic whiskers are selected from Si3N4 whiskers with a diameter of 0.1~1µm, a length of 5~20µm, and an aspect ratio of 5~20; the rare earth oxide powder is selected from Y2O3 powder.

2. The resistive paste as described in claim 1, characterized in that, The ruthenium dioxide powder has a particle size of 0.1~5μm.

3. The resistive paste as described in claim 1, characterized in that, The particle size of the nano-silver powder is 10~300nm; And / or, the particle size of the glass powder is 0.5~3μm.

4. The resistive paste as described in claim 1, characterized in that, The resistive slurry has a fineness of ≤10μm and a viscosity of 50~300Pa·s.

5. The resistive paste as described in claim 1, characterized in that, The high-temperature heat-resistant agent also includes an organic solvent, which includes ethylene glycol, polyvinyl butyral, and diethylene glycol monobutyl ether in a mass ratio of (1~10):(1~5):(20~40).

6. The resistive paste as described in claim 5, characterized in that, The organic solvent accounts for 70-90% of the total mass of the high-temperature heat-resistant agent.

7. The resistive paste as described in claim 1, characterized in that, The organic carrier comprises 5-10 parts of ethyl cellulose, 3-6 parts of ethylene glycol, 6-12 parts of diethylene glycol monobutyl ether, and 1-5 parts of terpineol.

8. A method for preparing the resistive paste as described in claim 5 or 6, characterized in that, Includes the following steps: A high-temperature heat-resistant agent is added to an organic carrier and mixed to obtain a dispersion. The conductive filler and glass powder are added to the dispersion liquid for dispersion treatment, and then subjected to three-roll ball milling and filtration to obtain the resistive slurry.

9. The preparation method according to claim 8, characterized in that, The steps for preparing the glass powder include: mixing a composite oxide of silver and cerium, bismuth oxide, aluminum oxide, silicon dioxide, barium carbonate, phosphoric acid, and zinc oxide, followed by melting, cooling, crushing, and sieving to obtain glass powder; the melting temperature is 1000~1200℃ and the time is 10~60min. And / or, the step of preparing the high-temperature heat-resistant agent includes: adding the metal oxide solid solution powder, the inorganic whiskers and the rare earth oxide powder to the organic solvent and mixing them to obtain the high-temperature heat-resistant agent.

10. The preparation method according to claim 9, characterized in that, The steps for preparing the silver-cerium composite oxide include: dissolving silver salt and cerium salt in a solvent, then co-precipitating them with a precipitant, followed by solid-liquid separation, purification, and drying to obtain a silver-cerium composite hydroxide; calcining the silver-cerium composite hydroxide to obtain a silver-cerium composite oxide; the calcination temperature is 500~700℃.

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