Zinc oxide resistor with high stability and low cost and preparation method thereof

Abstract

The invention belongs to the technical field of resistor electrical elements, and particularly relates to a zinc oxide resistor with high stability and low cost and a preparation method thereof. The zinc oxide resistor comprises the following components: large-particle-size zinc oxide elementary substance powder, small-particle-size zinc oxide elementary substance powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganous-manganic oxide, cobaltosic oxide, nano tin powder, diboron trioxide, nano silver powder, a binder, a dispersant and deionized water. The invention provides the preparation method of the resistor disc with low cost and high through-current impact stability, large through-current is realized, the stability is relatively good after large-current pulse surge impact, the cost is low, the resistor disc can meet the application requirements of more occasions, the cost is low, and the resistor disc is suitable for industrial popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of resistive electrical components, and particularly relates to a zinc oxide resistor with high stability and low cost and a preparation method thereof. Background Art

[0002] A zinc oxide varistor is a semiconductor ceramic resistor with non-linear volt-ampere characteristics. Varistors generally have a voltage threshold, which is generally called the critical voltage. When the applied voltage is lower than the critical voltage, the current passing through the varistor is very small and the internal resistance of the varistor itself is very large. When the applied voltage exceeds the critical voltage, the internal resistance decreases sharply and the current flowing through the varistor increases exponentially. Due to its special functionality, it has a wide range of applications in fields such as high-voltage and low-voltage power systems and the semiconductor industry.

[0003] The origin of the non-linear I-V characteristics of zinc oxide varistors comes from the formation of back-to-back Schottky barriers at the grain boundaries around a large number of adjacent two zinc oxide grains. It is precisely due to this bilateral barrier that the zinc oxide varistor obtains the voltage-sensitive characteristic. However, large current surge impacts inevitably affect the barriers at the zinc oxide grain boundaries, and the degradation behavior of zinc oxide varistors under high surge impacts is an important factor restricting their development. Therefore, it is crucial to improve the electrical properties of zinc oxide varistors, especially in the manufacture of zinc oxide varistors with large current-carrying capacity and high pulse surge impact stability, which has become an urgent technical problem to be solved. At present, many studies only focus on the research of three parameters, while ignoring the influence of current-carrying capacity and stability on zinc oxide varistors. Therefore, a suitable raw material formula and additive content are one of the keys to preparing resistor chips with high gradient, low resistivity, and high stability.

[0004] In order to solve the problems of the existing technology, the purpose of the present invention is to overcome the deficiencies of the existing technology and provide a preparation method of resistor chips with low cost and large current surge impact stability. The prepared zinc oxide varistor can achieve large current-carrying capacity and has good stability after being impacted by large current pulse surges, and has low cost, so that it can meet the application requirements of more occasions. The process of the present invention is simple, easy to control, and has low cost, and is suitable for industrial promotion. Summary of the Invention

[0005] The present invention aims to provide a zinc oxide resistor with high stability and low cost and a preparation method thereof. Through improvements in related processes and raw materials, it has a good improvement effect on the degradation behavior of zinc oxide varistors caused by the influence of grain boundary barriers under large current surge impacts.

[0006] Highlights of this method: 1. During the preparation of the large-particle-size mixture, it is necessary to ensure that bismuth stannate can effectively coat the surface of zinc oxide. Since the powder particle size of bismuth stannate is small and the specific surface area is large, it has a good adsorption effect on the surface of zinc oxide. After heat treatment, the adhesion effect of bismuth stannate on the surface of zinc oxide is strengthened, and the uniform distribution of bismuth stannate is beneficial to reducing the sintering temperature and the grain size of the material during the subsequent sintering process; 2. During the preparation of the small-particle-size mixture, segmented mixing is required. High-energy ball milling is used to reduce the particle size of some oxides. Silver is added during the second-stage ball milling process to utilize the effect of silver as a binder, and vacuum heat treatment is used to strengthen the adhesion effect between the powders by using the low melting point characteristic of tin; 3. In order to reduce the sintering temperature and improve the sintering density of the material, it is necessary to improve the green density as much as possible. Heating during the pressing process of the green body is beneficial to the softening of tin and filling into the pores, increasing the strength and density of the green body.

[0007] The specific implementation scheme of a zinc oxide resistor with high stability and low cost and its preparation method involved in the present invention is as follows: The raw materials of a zinc oxide resistor with high stability and low cost include large-particle-size zinc oxide single-substance powder, small-particle-size zinc oxide single-substance powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, nano-silver powder, binder, dispersant, deionized water; Measured by mass parts, among them: 40 - 70 parts of large-particle-size zinc oxide single-substance powder, 10 - 20 parts of small-particle-size zinc oxide single-substance powder, 1 - 3 parts of bismuth trioxide, 2 - 5 parts of bismuth stannate, 0.5 - 2 parts of nickel monoxide, 0.2 - 2 parts of manganese tetroxide, 0.5 - 3 parts of cobalt tetroxide, 0.5 - 1.5 parts of nano-tin powder, 0.3 - 1 part of boron trioxide, 0.01 - 0.05 parts of nano-silver powder, 1 - 3 parts of binder, 0.5 - 1.5 parts of dispersant, 320 - 450 parts of deionized water; The small-particle-size zinc oxide single-substance powder has a D50 of 30 - 70 nm spherical powder; The large-particle-size zinc oxide single-substance powder has a D50 of 100 - 300 nm spherical powder; The bismuth stannate powder has a D50 of 10 - 30 nm; The nano-silver powder has a D50 of 20 - 50 nm spherical powder; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include steps such as the preparation of the large-particle-size mixture, the preparation of the small-particle-size mixture, the preparation of the dry-pressed powder, the preparation of the green body block, sintering, etc. The specific implementation process is as follows: The preparation process of the large particle size mixture is as follows: The first step: Mix the large particle size zinc oxide single powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 200 - 300 rpm and a time of 1 - 3 h; The second step: Heat-treat the first-stage mixture. The heat treatment temperature is 500 - 700 °C, and the heat treatment time is 30 - 60 min; The third step: Disperse and screen the heat-treated first-stage mixture to obtain the large particle size mixture. The dispersion method is jet milling, and the powder particle size is 200 - 400 nm; The preparation process of the small particle size mixture is as follows: The first step: Mix nickel oxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, with a rotation speed of 300 - 500 rpm and a time of 1 - 3 h; The second step: Mix the oxide mixture, nano-tin powder, small particle size zinc oxide single powder, and nano-silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 200 - 300 rpm and a time of 2 - 3 h; The third step: Vacuum heat-treat the second-stage mixture. The heat treatment temperature is 240 - 260 °C, and the heat treatment time is 30 - 60 min; The fourth step: Disperse and screen the heat-treated second-stage mixture to obtain the small particle size mixture. The dispersion method is jet milling, and the powder particle size is 70 - 150 nm; The preparation process of the dry-pressed powder is as follows: The first step: Dissolve the binder and dispersant in deionized water and stir well to obtain a glue solution. The stirring method is mechanical stirring, with a rotation speed of 300 - 500 rpm and a time of 30 - 60 min; The second step: Wet ball mill and screen the large particle size mixture, small particle size mixture, and glue solution to obtain a granulating slurry. The ball milling time is 20 - 30 h, the rotation speed is 100 - 300 rpm, and the mesh number of the sieve is 120 - 200 meshes; The third step: Use a spray dryer to perform spray granulation on the granulating slurry to obtain the dry-pressed powder. The spray granulation temperature is 150 - 180 °C; The preparation process of the green compact is as follows: Press the dry-pressed powder with a dry press to obtain a green compact. During the dry pressing process, heat the pressing die simultaneously. The heating temperature is 180 - 220 °C, the dry pressing pressure is 200 - 300 Mpa, and the pressure holding time is 1 - 5 min; The preparation process of the sintering is as follows: Step 1: Debind the green compact. The debinding temperature is 450 - 550°C, the atmosphere is air, and the debinding time is 60 - 90 min. Step 2: Sinter the debound green compact to obtain a resistor chip blank. The sintering temperature is 900 - 1000°C, and the sintering time is 1 - 3 h. Step 3: Grind and clean the resistor chip blank, and then prepare silver electrodes on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The method for preparing the silver electrodes is screen printing. The thickness of the silver electrodes is 50 - 150 μm, and the sintering temperature of the silver electrodes is 600 - 650°C.

[0008] Compared with the prior art, the present invention has the following beneficial effects: (1) In the method designed by the present invention, by adjusting the ratio of each raw material in the resistor chip material and pre-treating zinc oxide with different particle sizes, it is beneficial to reduce the porosity of the material after sintering, improve the material density, and realize the preparation of resistor chips with high gradient, large current-carrying capacity and good stability. (2) In the method designed by the present invention, the large-particle zinc oxide single powder and bismuth stannate are pre-treated. During the high-temperature sintering process, bismuth stannate is beneficial to accelerate the diffusion effect between the powders, reduce the sintering temperature of the material, reduce the grain size and production cost caused by high-temperature sintering of the material, and has an improvement effect on the degradation behavior of zinc oxide varistors caused by the existing large-current surge impact. (3) In the method designed by the present invention, heating is carried out synchronously during the pressing process of the green compact. Because single-nanometer tin powder is added to the material, compared with ordinary cold pressing treatment, the density of the green compact of the material is greatly improved, the high-temperature sintering diffusion ability of the material is improved, a liquid phase is generated during the sintering process, the sintering density is effectively improved, and the performance is improved. During the sintering process in an air atmosphere, tin will also be oxidized to tin dioxide. Description of the Drawings

[0009] Figure 1 It is a preparation flow chart of a zinc oxide resistor with high stability and low cost and its preparation method. Detailed Embodiments

[0010] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Embodiment

[0011] A zinc oxide resistor raw material with high stability and low cost includes large-particle-size zinc monoxide single powder, small-particle-size zinc monoxide single powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, nano-silver powder, binder, dispersant, and deionized water; Measured by mass parts, where: 40 parts of large-particle-size zinc monoxide single powder, 10 parts of small-particle-size zinc monoxide single powder, 1 part of bismuth trioxide, 2 parts of bismuth stannate, 0.5 part of nickel monoxide, 0.2 part of manganese tetroxide, 0.5 part of cobalt tetroxide, 0.5 part of nano-tin powder, 0.3 part of boron trioxide, 0.01 part of nano-silver powder, 1 part of binder, 0.5 part of dispersant, and 320 parts of deionized water; The small-particle-size zinc monoxide single powder is a spherical powder with a D50 of 30 nm; The large-particle-size zinc monoxide single powder is a spherical powder with a D50 of 100 nm; The bismuth stannate powder has a D50 of 10 nm; The nano-silver powder is a spherical powder with a D50 of 20 nm; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include steps such as the preparation of large-particle-size mixture, the preparation of small-particle-size mixture, the preparation of dry-pressed powder, the preparation of green compact, and sintering. The specific implementation process is as follows: The preparation process of the large-particle-size mixture is as follows: First step: Mix the large-particle-size zinc monoxide single powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 200 rpm, and the time is 1 h; Second step: Heat-treat the first-stage mixture. The heat-treatment temperature is 500 °C, and the heat-treatment time is 30 min; Third step: Disperse and screen the heat-treated first-stage mixture to obtain a large-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 200 nm; The preparation process of the small-particle-size mixture is as follows: First step: Mix nickel monoxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, the rotation speed is 300 rpm, and the time is 1 h; Second step: Mix the oxide mixture, nano-tin powder, small-particle-size zinc monoxide single powder, and nano-silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 200 rpm, and the time is 2 h; Step 3: Subject the two-stage mixture to vacuum heat treatment at a heat treatment temperature of 240 °C for 30 min; Step 4: Disperse and screen the heat-treated two-stage mixture to obtain a small-particle-size mixture. The dispersion method is a jet mill, and the particle size of the powder is 70 nm; The preparation process of the dry-pressed powder is as follows: Step 1: Dissolve the binder and dispersant in deionized water, and fully stir to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 300 rpm, and the time is 30 min; Step 2: Wet ball mill and screen the large-particle-size mixture, small-particle-size mixture, and glue solution to obtain a granulation slurry. The ball milling time is 20 h, the rotation speed is 100 rpm, and the mesh number of the sieve is 120 meshes; Step 3: Use a spray dryer to perform spray granulation on the granulation slurry to obtain dry-pressed powder. The spray granulation temperature is 150 °C; The preparation process of the green compact is as follows: Use a dry press to press the dry-pressed powder to obtain a green compact. During the dry pressing process, heat the pressing die simultaneously. The heating temperature is 180 °C, the dry pressing pressure is 200 Mpa, and the pressure holding time is 1 min; The preparation process of the sintering is as follows: Step 1: Subject the green compact to degumming treatment at a degumming temperature of 450 °C, in an air atmosphere, and the degumming time is 60 min; Step 2: Subject the degummed green compact to sintering treatment to obtain a resistor chip blank. The sintering temperature is 900 °C, and the sintering time is 1 h; Step 3: Grind and clean the resistor chip blank, and then prepare a silver electrode on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The silver electrode preparation method is screen printing, the silver electrode thickness is 50 μm, and the silver electrode sintering temperature is 600 °C. Example

[0012] A zinc oxide resistor raw material with high stability and low cost includes large-particle-size zinc monoxide single powder, small-particle-size zinc monoxide single powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, nano-silver powder, binder, dispersant, and deionized water; Measured by mass parts, wherein: 70 parts of large-particle-size zinc monoxide single powder, 20 parts of small-particle-size zinc monoxide single powder, 3 parts of bismuth trioxide, 5 parts of bismuth stannate, 2 parts of nickel monoxide, 2 parts of manganese tetroxide, 3 parts of cobalt tetroxide, 1.5 parts of nano-tin powder, 1 part of boron trioxide, 0.05 part of nano-silver powder, 3 parts of binder, 1.5 parts of dispersant, and 450 parts of deionized water; The small-particle-size zinc oxide elemental powder has a D50 of 70 nm and is a spherical powder; The large-particle-size zinc oxide elemental powder has a D50 of 300 nm and is a spherical powder; The bismuth stannate powder has a D50 of 30 nm; The nano silver powder has a D50 of 50 nm and is a spherical powder; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include the preparation of a large-particle-size mixture, the preparation of a small-particle-size mixture, the preparation of a dry-pressed powder, the preparation of a green compact, sintering and other steps. The specific implementation process is as follows: The preparation process of the large-particle-size mixture is as follows: The first step: Mix the large-particle-size zinc oxide elemental powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 300 rpm, and the time is 3 h; The second step: Heat-treat the first-stage mixture. The heat-treatment temperature is 700 °C, and the heat-treatment time is 60 min; The third step: Disperse and screen the heat-treated first-stage mixture to obtain a large-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 400 nm; The preparation process of the small-particle-size mixture is as follows: The first step: Mix nickel oxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, the rotation speed is 500 rpm, and the time is 3 h; The second step: Mix the oxide mixture, nano tin powder, small-particle-size zinc oxide elemental powder, and nano silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 300 rpm, and the time is 3 h; The third step: Vacuum heat-treat the second-stage mixture. The heat-treatment temperature is 260 °C, and the heat-treatment time is 60 min; The fourth step: Disperse and screen the heat-treated second-stage mixture to obtain a small-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 150 nm; The preparation process of the dry-pressed powder is as follows: The first step: Dissolve the binder and the dispersant in deionized water, and fully stir to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 500 rpm, and the time is 60 min; The second step: Wet-mill and screen the large-particle-size mixture, the small-particle-size mixture, and the glue solution to obtain a granulation slurry. The ball milling time is 30 h, the rotation speed is 300 rpm, and the mesh number of the sieve is 200 mesh; Step 3: Use a spray dryer to perform spray granulation on the granulated slurry to obtain dry-pressed powder. The spray granulation temperature is 180 °C; The preparation process of the green compact is as follows: Use a dry press to press the dry-pressed powder to obtain a green compact. During the dry pressing process, heat the pressing die simultaneously. The heating temperature is 220 °C, the dry pressing pressure is 300 Mpa, and the pressure holding time is 5 min; The preparation process of the sintering is as follows: Step 1: Debind the green compact. The debinding temperature is 550 °C, the atmosphere is air, and the debinding time is 90 min; Step 2: Sinter the debound green compact to obtain a resistor chip blank. The sintering temperature is 1000 °C, and the sintering time is 3 h; Step 3: Grind and clean the resistor chip blank, and then prepare silver electrodes on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The method for preparing the silver electrodes is screen printing. The thickness of the silver electrodes is 150 μm, and the sintering temperature of the silver electrodes is 650 °C. Example

[0013] A zinc oxide resistor raw material with high stability and low cost includes large-particle-size zinc oxide single powder, small-particle-size zinc oxide single powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, nano-silver powder, binder, dispersant, deionized water; Measured by mass fraction, where: 60 parts of large-particle-size zinc oxide single powder, 15 parts of small-particle-size zinc oxide single powder, 2 parts of bismuth trioxide, 3 parts of bismuth stannate, 1.5 parts of nickel monoxide, 1.2 parts of manganese tetroxide, 2 parts of cobalt tetroxide, 1 part of nano-tin powder, 0.7 part of boron trioxide, 0.03 part of nano-silver powder, 2 parts of binder, 1 part of dispersant, 400 parts of deionized water; The small-particle-size zinc oxide single powder is a spherical powder with a D50 of 50 nm; The large-particle-size zinc oxide single powder is a spherical powder with a D50 of 200 nm; The D50 of the bismuth stannate powder is 20 nm; The nano-silver powder is a spherical powder with a D50 of 30 nm; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include steps such as the preparation of a large-particle-size mixture, the preparation of a small-particle-size mixture, the preparation of dry-pressed powder, the preparation of a green compact, and sintering. The specific implementation process is as follows: The preparation process of the large-particle-size mixture is as follows: The first step: Mix the large-particle-size zinc oxide single powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 250 rpm and a time of 2 h; The second step: Heat-treat the first-stage mixture. The heat-treatment temperature is 600 °C and the heat-treatment time is 40 min; The third step: Disperse and screen the heat-treated first-stage mixture to obtain the large-particle-size mixture. The dispersion method is jet milling and the powder particle size is 300 nm; The preparation process of the small-particle-size mixture is as follows: The first step: Mix nickel oxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, with a rotation speed of 400 rpm and a time of 2 h; The second step: Mix the oxide mixture, nano-tin powder, small-particle-size zinc oxide single powder, and nano-silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 250 rpm and a time of 2 h; The third step: Vacuum heat-treat the second-stage mixture. The heat-treatment temperature is 250 °C and the heat-treatment time is 40 min; The fourth step: Disperse and screen the heat-treated second-stage mixture to obtain the small-particle-size mixture. The dispersion method is jet milling and the powder particle size is 100 nm; The preparation process of the dry-pressed powder is as follows: The first step: Dissolve the binder and dispersant in deionized water and stir well to obtain a glue solution. The stirring method is mechanical stirring, with a rotation speed of 400 rpm and a time of 50 min; The second step: Wet-mill and screen the large-particle-size mixture, small-particle-size mixture, and glue solution to obtain a granulation slurry. The ball milling time is 25 h, the rotation speed is 200 rpm, and the mesh number of the sieve is 180 meshes; The third step: Use a spray dryer to perform spray granulation on the granulation slurry to obtain the dry-pressed powder. The spray granulation temperature is 160 °C; The preparation process of the green compact is as follows: Press the dry-pressed powder with a dry press to obtain the green compact. During the dry pressing process, heat the pressing die simultaneously. The heating temperature is 200 °C, the dry pressing pressure is 250 Mpa, and the pressure holding time is 3 min; The preparation process of the sintering is as follows: The first step: Debind the green compact. The debinding temperature is 500 °C, the atmosphere is air, and the debinding time is 70 min; Step 2: Sinter the debound green body blocks to obtain the resistor sheet blanks, with a sintering temperature of 950 °C and a sintering time of 2 h; Step 3: Grind and clean the resistor sheet blanks, and then prepare silver electrodes on the surface of the treated resistor sheet blanks to obtain the finished zinc oxide resistor. The method for preparing the silver electrodes is screen printing, the thickness of the silver electrodes is 100 um, and the sintering temperature of the silver electrodes is 620 °C.

[0014] Comparative Example 1 A zinc oxide resistor raw material with high stability and low cost includes large particle size zinc oxide single powder, small particle size zinc oxide single powder, bismuth trioxide, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano tin powder, boron trioxide, nano silver powder, binder, dispersant, deionized water; Measured by mass parts, where: 60 parts of large particle size zinc oxide single powder, 15 parts of small particle size zinc oxide single powder, 2 parts of bismuth trioxide, 1.5 parts of nickel monoxide, 1.2 parts of manganese tetroxide, 2 parts of cobalt tetroxide, 1 part of nano tin powder, 0.7 part of boron trioxide, 0.03 part of nano silver powder, 2 parts of binder, 1 part of dispersant, 400 parts of deionized water; The small particle size zinc oxide single powder is a spherical powder with a D50 of 50 nm; The large particle size zinc oxide single powder is a spherical powder with a D50 of 200 nm; The nano silver powder is a spherical powder with a D50 of 30 nm; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include steps such as the preparation of small particle size mixtures, the preparation of dry-pressed powders, the preparation of green body blocks, sintering, etc. The specific implementation process is as follows: The preparation process of the small particle size mixture is as follows: Step 1: Mix nickel monoxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, with a rotation speed of 400 rpm and a time of 2 h; Step 2: Mix the oxide mixture, nano tin powder, small particle size zinc oxide single powder, and nano silver powder to obtain a two-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 250 rpm and a time of 2 h; Step 3: Perform vacuum heat treatment on the two-stage mixture. The heat treatment temperature is 250 °C and the heat treatment time is 40 min; Step 4: Disperse and screen the heat-treated two-stage mixture to obtain a small particle size mixture. The dispersion method is air jet milling, and the powder particle size is 100 nm; The preparation process of the dry-pressed powder is as follows: The first step: Dissolve the binder and dispersant in deionized water, and fully stir to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 400 rpm, and the time is 50 min; The second step: Wet ball-mill and screen the large-particle-size zinc oxide single-element powder, small-particle-size mixture, and glue solution to obtain a granulation slurry. The ball-milling time is 25 h, the rotation speed is 200 rpm, and the mesh number of the sieve is 180 meshes; The third step: Use a spray dryer to perform spray granulation on the granulation slurry to obtain dry-pressed powder. The spray granulation temperature is 160 °C; The preparation process of the green compact is as follows: Press the dry-pressed powder with a dry press to obtain a green compact. During the dry pressing process, heat the pressing die at the same time. The heating temperature is 200 °C, the dry pressing pressure is 250 Mpa, and the pressure holding time is 3 min; The preparation process of the sintering is as follows: The first step: Perform debinding treatment on the green compact. The debinding temperature is 500 °C, the atmosphere is air, and the debinding time is 70 min; The second step: Sinter the debound green compact to obtain a resistor chip blank. The sintering temperature is 950 °C, and the sintering time is 2 h; The third step: Grind and clean the resistor chip blank, and then prepare silver electrodes on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The silver electrode preparation method is screen printing, the silver electrode thickness is 100 μm, and the silver electrode sintering temperature is 620 °C.

[0015] Comparative Example 2 A zinc oxide resistor raw material with high stability and low cost includes large-particle-size zinc oxide single-element powder, small-particle-size zinc oxide single-element powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, boron trioxide, nano silver powder, binder, dispersant, deionized water; Measured by mass parts dosage, among them: 60 parts of large-particle-size zinc oxide single-element powder, 15 parts of small-particle-size zinc oxide single-element powder, 2 parts of bismuth trioxide, 3 parts of bismuth stannate, 1.5 parts of nickel monoxide, 1.2 parts of manganese tetroxide, 2 parts of cobalt tetroxide, 0.7 part of boron trioxide, 0.03 part of nano silver powder, 2 parts of binder, 1 part of dispersant, 400 parts of deionized water; The small-particle-size zinc oxide single-element powder has a D50 of 50 nm spherical powder; The large-particle-size zinc oxide single-element powder has a D50 of 200 nm spherical powder; The bismuth stannate powder has a D50 of 20 nm; The D50 of the silver nanometer powder is a spherical powder with a size of 30 nm; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and a preparation method thereof respectively include steps of preparing a large particle size mixture, preparing a small particle size mixture, preparing a dry-pressed powder, preparing a green compact, sintering, etc. The specific implementation process is as follows: The preparation process of the large particle size mixture is as follows: First step: Mix the large particle size zinc oxide single substance powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; Second step: Heat-treat the first-stage mixture. The heat treatment temperature is 600 °C, and the heat treatment time is 40 min; Third step: Disperse and sieve the heat-treated first-stage mixture to obtain a large particle size mixture. The dispersion method is jet milling, and the powder particle size is 300 nm; The preparation process of the small particle size mixture is as follows: First step: Mix nickel oxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, the rotation speed is 400 rpm, and the time is 2 h; Second step: Mix the oxide mixture, small particle size zinc oxide single substance powder, and silver nanometer powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; Third step: Vacuum heat-treat the second-stage mixture. The heat treatment temperature is 250 °C, and the heat treatment time is 40 min; Fourth step: Disperse and sieve the heat-treated second-stage mixture to obtain a small particle size mixture. The dispersion method is jet milling, and the powder particle size is 100 nm; The preparation process of the dry-pressed powder is as follows: First step: Dissolve the binder and the dispersant in deionized water, and fully stir to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 400 rpm, and the time is 50 min; Second step: Wet ball mill and sieve the large particle size mixture, small particle size mixture, and glue solution to obtain a granulating slurry. The ball milling time is 25 h, the rotation speed is 200 rpm, and the mesh number of the sieve is 180 mesh; Third step: Use a spray dryer to perform spray granulation treatment on the granulating slurry to obtain a dry-pressed powder. The spray granulation temperature is 160 °C; The preparation process of the green compact is as follows: The dry-pressed powder is tableted using a dry press to obtain a green compact. During the dry pressing process, the tablet die is heated simultaneously. The heating temperature is 200 °C, the dry pressing pressure is 250 Mpa, and the pressure holding time is 3 min; The preparation process of the sintering is as follows: The first step: The green compact is subjected to degumming treatment. The degumming temperature is 500 °C, the atmosphere is air, and the degumming time is 70 min; The second step: The degummed green compact is sintered to obtain a resistor chip blank. The sintering temperature is 950 °C, and the sintering time is 2 h; The third step: The resistor chip blank is ground and cleaned, and then silver electrodes are prepared on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The method for preparing the silver electrodes is screen printing. The thickness of the silver electrodes is 100 um, and the sintering temperature of the silver electrodes is 620 °C.

[0016] Comparative Example 3 A zinc oxide resistor raw material with high stability and low cost includes large-particle-size zinc oxide single powder, small-particle-size zinc oxide single powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, binder, dispersant, deionized water; Measured by mass parts, where: 60 parts of large-particle-size zinc oxide single powder, 15 parts of small-particle-size zinc oxide single powder, 2 parts of bismuth trioxide, 3 parts of bismuth stannate, 1.5 parts of nickel monoxide, 1.2 parts of manganese tetroxide, 2 parts of cobalt tetroxide, 1 part of nano-tin powder, 0.7 part of boron trioxide, 2 parts of binder, 1 part of dispersant, 400 parts of deionized water; The small-particle-size zinc oxide single powder has a D50 of 50 nm spherical powder; The large-particle-size zinc oxide single powder has a D50 of 200 nm spherical powder; The bismuth stannate powder has a D50 of 20 nm; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include steps such as the preparation of a large-particle-size mixture, the preparation of a small-particle-size mixture, the preparation of dry-pressed powder, the preparation of a green compact, sintering, etc. The specific implementation process is as follows: The preparation process of the large-particle-size mixture is as follows: The first step: The large-particle-size zinc oxide single powder and bismuth stannate powder are mixed to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; The second step: The first-stage mixture is heat-treated. The heat treatment temperature is 600 °C, and the heat treatment time is 40 min; Step 3: Disintegrate and screen the heat-treated mixture to obtain a large-particle-size mixture. The disintegration method is a jet mill, and the powder particle size is 300 nm. The preparation process of the small-particle-size mixture is as follows: Step 1: Mix nickel monoxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, the rotation speed is 400 rpm, and the time is 2 h. Step 2: Mix the oxide mixture, nano-tin powder, and small-particle-size zinc oxide single-substance powder to obtain a two-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h. Step 3: Perform vacuum heat treatment on the two-stage mixture. The heat treatment temperature is 250 °C, and the heat treatment time is 40 min. Step 4: Disintegrate and screen the heat-treated two-stage mixture to obtain a small-particle-size mixture. The disintegration method is a jet mill, and the powder particle size is 100 nm. The preparation process of the dry-pressed powder is as follows: Step 1: Dissolve the binder and dispersant in deionized water, and stir well to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 400 rpm, and the time is 50 min. Step 2: Perform wet ball milling and screening on the large-particle-size mixture, small-particle-size mixture, and glue solution to obtain a granulation slurry. The ball milling time is 25 h, the rotation speed is 200 rpm, and the mesh number of the sieve is 180 meshes. Step 3: Use a spray dryer to perform spray granulation on the granulation slurry to obtain dry-pressed powder. The spray granulation temperature is 160 °C. The preparation process of the green compact is as follows: Press the dry-pressed powder using a dry press to obtain a green compact. During the dry pressing process, heat the pressing die simultaneously. The heating temperature is 200 °C, the dry pressing pressure is 250 Mpa, and the pressure holding time is 3 min. The preparation process of the sintering is as follows: Step 1: Perform debinding on the green compact. The debinding temperature is 500 °C, the atmosphere is air, and the debinding time is 70 min. Step 2: Perform sintering on the debound green compact to obtain a resistor chip blank. The sintering temperature is 950 °C, and the sintering time is 2 h. Step 3: Grind and clean the resistor chip blank, and then prepare a silver electrode on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The silver electrode preparation method is screen printing, the silver electrode thickness is 100 um, and the silver electrode sintering temperature is 620 °C.

[0017] Comparative Example 4 A zinc oxide resistor raw material with high stability and low cost includes zinc monoxide, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, nano-silver powder, binder, dispersant, and deionized water; Measured by mass parts, among which: 75 parts of zinc monoxide, 2 parts of bismuth trioxide, 3 parts of bismuth stannate, 1.5 parts of nickel monoxide, 1.2 parts of manganese tetroxide, 2 parts of cobalt tetroxide, 1 part of nano-tin powder, 0.7 part of boron trioxide, 0.03 part of nano-silver powder, 2 parts of binder, 1 part of dispersant, and 400 parts of deionized water; The zinc monoxide has a spherical powder with a D50 of 200 nm; The bismuth stannate powder has a D50 of 20 nm; The nano-silver powder has a spherical powder with a D50 of 30 nm; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include the preparation of zinc monoxide - bismuth stannate composite, the preparation of zinc monoxide - silver composite, the preparation of dry-pressed powder, the preparation of green compact, sintering and other steps. The specific implementation process is as follows: The preparation process of the zinc monoxide - bismuth stannate composite is as follows: First step: Mix 60 parts of zinc monoxide with bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; Second step: Heat-treat the first-stage mixture. The heat-treatment temperature is 600 °C, and the heat-treatment time is 40 min; Third step: Disperse and screen the heat-treated first-stage mixture to obtain a zinc monoxide - bismuth stannate composite. The dispersion method is jet milling, and the powder particle size is 300 nm; The preparation process of the zinc monoxide - silver composite is as follows: First step: Mix nickel monoxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, the rotation speed is 400 rpm, and the time is 2 h; Second step: Mix the oxide mixture, nano-tin powder, 15 parts of zinc monoxide, and nano-silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; Third step: Vacuum heat-treat the second-stage mixture. The heat-treatment temperature is 250 °C, and the heat-treatment time is 40 min; Step 4: Disintegrate the heat-treated two-stage mixture and screen it to obtain a zinc oxide-silver composite. The disintegration method is a jet mill, and the particle size of the powder is 100 nm; The preparation process of the dry-pressed powder is as follows: Step 1: Dissolve the binder and dispersant in deionized water, and fully stir to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 400 rpm, and the time is 50 min; Step 2: Wet ball-mill and screen the zinc oxide-bismuth stannate composite, zinc oxide-silver composite, and glue solution to obtain a granulating slurry. The ball-milling time is 25 h, the rotation speed is 200 rpm, and the mesh number of the sieve is 180 meshes; Step 3: Use a spray dryer to perform spray granulation on the granulating slurry to obtain dry-pressed powder. The spray granulation temperature is 160 °C; The preparation process of the green compact is as follows: Press the dry-pressed powder with a dry press to obtain a green compact. During the dry pressing process, heat the pressing die simultaneously. The heating temperature is 200 °C, the dry pressing pressure is 250 Mpa, and the pressure holding time is 3 min; The preparation process of the sintering is as follows: Step 1: Debind the green compact. The debinding temperature is 500 °C, the atmosphere is air, and the debinding time is 70 min; Step 2: Sinter the debound green compact to obtain a resistor chip blank. The sintering temperature is 950 °C, and the sintering time is 2 h; Step 3: Grind and clean the resistor chip blank, and then prepare a silver electrode on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The silver electrode preparation method is screen printing, the silver electrode thickness is 100 μm, and the silver electrode sintering temperature is 620 °C.

[0018] Comparative Example 5 A zinc oxide resistor raw material with high stability and low cost includes large-particle-size zinc oxide elemental powder, small-particle-size zinc oxide elemental powder, bismuth trioxide, bismuth stannate, nickel monoxide, manganese tetroxide, cobalt tetroxide, nano-tin powder, boron trioxide, nano-silver powder, binder, dispersant, and deionized water; Measured by mass parts dosage, where: 60 parts of large-particle-size zinc oxide elemental powder, 15 parts of small-particle-size zinc oxide elemental powder, 2 parts of bismuth trioxide, 3 parts of bismuth stannate, 1.5 parts of nickel monoxide, 1.2 parts of manganese tetroxide, 2 parts of cobalt tetroxide, 1 part of nano-tin powder, 0.7 part of boron trioxide, 0.03 part of nano-silver powder, 2 parts of binder, 1 part of dispersant, and 400 parts of deionized water; The small-particle-size zinc oxide elemental powder is a spherical powder with a D50 of 50 nm; The large-particle-size zinc oxide single powder has a D50 of 200 nm and is a spherical powder; The bismuth stannate powder has a D50 of 20 nm; The nano silver powder has a D50 of 30 nm and is a spherical powder; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid; A zinc oxide resistor with high stability and low cost and its preparation method respectively include steps such as the preparation of a large-particle-size mixture, the preparation of a small-particle-size mixture, the preparation of a dry-pressed powder, the preparation of a green compact, and sintering. The specific implementation process is as follows: The preparation process of the large-particle-size mixture is as follows: First step: Mix the large-particle-size zinc oxide single powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; Second step: Heat-treat the first-stage mixture. The heat-treatment temperature is 600 °C, and the heat-treatment time is 40 min; Third step: Disperse and screen the heat-treated first-stage mixture to obtain a large-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 300 nm; The preparation process of the small-particle-size mixture is as follows: First step: Mix nickel oxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, the rotation speed is 400 rpm, and the time is 2 h; Second step: Mix the oxide mixture, nano tin powder, small-particle-size zinc oxide single powder, and nano silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, the rotation speed is 250 rpm, and the time is 2 h; Third step: Vacuum heat-treat the second-stage mixture. The heat-treatment temperature is 250 °C, and the heat-treatment time is 40 min; Fourth step: Disperse and screen the heat-treated second-stage mixture to obtain a small-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 100 nm; The preparation process of the dry-pressed powder is as follows: First step: Dissolve the binder and dispersant in deionized water and fully stir to obtain a glue solution. The stirring method is mechanical stirring, the rotation speed is 400 rpm, and the time is 50 min; Second step: Wet ball mill and screen the large-particle-size mixture, small-particle-size mixture, and glue solution to obtain a granulation slurry. The ball milling time is 25 h, the rotation speed is 200 rpm, and the mesh number of the sieve is 180 mesh; Step 3: Use a spray dryer to perform spray granulation on the granulated slurry to obtain dry-pressed powder, and the spray granulation temperature is 160°C; The preparation process of the green compact is as follows: Use a dry press to perform tablet pressing on the dry-pressed powder to obtain a green compact, with a dry pressing pressure of 250 Mpa and a pressure holding time of 3 min; The preparation process of the sintering is as follows: Step 1: Perform debinding on the green compact, with a debinding temperature of 500°C, an atmosphere of air, and a debinding time of 70 min; Step 2: Perform sintering on the debound green compact to obtain a resistor chip blank, with a sintering temperature of 950°C and a sintering time of 2 h; Step 3: Grind and clean the resistor chip blank, and then prepare silver electrodes on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The method for preparing the silver electrodes is screen printing, the thickness of the silver electrodes is 100 μm, and the sintering temperature of the silver electrodes is 620°C.

[0019] The test results are shown in Table 1: Table 1: Performance Test Preparation method Piezoelectric potential gradient V / mm Nonlinear coefficient Ratio of residual voltage of 5kA 8 / 20us lightning wave Example 1 295.63 31.33 1.65 Example 2 273.39 33.52 1.62 Example 3 343.16 36.17 1.58 Comparative example 1 253.22 25.23 1.71 Comparative example 2 234.75 24.82 1.79 Comparative example 3 223.39 24.12 1.75 Comparative example 4 213.66 22.79 1.86 Comparative example 5 252.18 25.84 1.73 Comparative Examples 1-5 in Table 1 were obtained by adjusting the experimental process or experimental parameters within the experimental parameters of Example 3. From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 1 in Table 1, it can be found that after removing bismuth stannate in the raw materials in Comparative Example 1, the sintering temperature in the sintering preparation process is still 950°C, which results in a lower sintering density of the final material, a decrease in the voltage gradient of the material after testing, and a decline in other properties. This shows that bismuth stannate is beneficial to improving the material properties on the basis of reducing the material sintering temperature; From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 2 in Table 1, it can be found that after removing nano-tin powder in the raw materials in Comparative Example 2, the sintering temperature in the sintering preparation process is still 950°C, which reduces the compaction density of the green compact and no liquid phase is generated during the sintering process, ultimately resulting in a decrease in the sintering density and a decline in the properties of the material after testing. This shows that nano-tin powder is beneficial to improving the green compact density and thus improving the material properties; From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 3 in Table 1, it can be found that after removing nano-silver powder in the raw materials in Comparative Example 3, the sintering temperature in the sintering preparation process is still 950°C. Although bismuth stannate and nano-tin powder in the material are beneficial to reducing the material sintering temperature, the lack of nano-powder causes a decrease in the uniformity of the distribution of each component in the material and segregation occurs, resulting in a decrease in all properties of the material in the final test. This also shows that nano-silver powder has a certain bonding effect and can play a role in evenly distributing the materials during the mixing process; From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 4 in Table 1, it can be found that in Comparative Example 4, the zinc monoxide powder was changed to the same powder with a D50 of 200 nm, which increased the internal pores during the material pressing process. In the subsequent sintering process, a sintering temperature of 950 °C could not obtain a dense zinc oxide resistor, ultimately resulting in a decline in the performance of the material; From the comparison of the experimental data of Examples 1, 2, 3 and Comparative Example 5 in Table 1, it can be found that in Comparative Example 5, the material was not heated simultaneously during the green compact pressing, which led to the inability of the nanosized tin powder to reach the molten state to fill the internal gaps of the green compact, resulting in a poor density of the obtained green compact. At a sintering temperature of 950 °C, it ultimately affected the sintering density of the material, thereby reducing the material performance.

[0020] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A zinc oxide resistor with high stability and low cost and a preparation method thereof, characterized in that, Including: Proportionally configuring raw materials and auxiliary materials, preparing large-particle-size mixtures, preparing small-particle-size mixtures, preparing dry-pressed powder, preparing green compact blocks, and sintering steps.

2. The preparation method according to claim 1, wherein, The proportionally configuring raw materials and auxiliary materials includes: Measuring by mass parts, where: 40 - 70 parts of large-particle-size zinc oxide elemental powder, 10 - 20 parts of small-particle-size zinc oxide elemental powder, 1 - 3 parts of bismuth trioxide, 2 - 5 parts of bismuth stannate, 0.5 - 2 parts of nickel monoxide, 0.2 - 2 parts of manganese tetroxide, 0.5 - 3 parts of cobalt tetroxide, 0.5 - 1.5 parts of nano-tin powder, 0.3 - 1 part of boron trioxide, 0.01 - 0.05 parts of nano-silver powder, 1 - 3 parts of binder, 0.5 - 1.5 parts of dispersant, and 320 - 450 parts of deionized water.

3. The preparation method according to claim 2, a zinc oxide resistor with high stability and low cost, characterized in that: The small-particle-size zinc oxide elemental powder has a D50 of 30 - 70 nm spherical powder; The large-particle-size zinc oxide elemental powder has a D50 of 100 - 300 nm spherical powder; The bismuth stannate powder has a D50 of 10 - 30 nm; The nano-silver powder has a D50 of 20 - 50 nm spherical powder; The binder is polyvinyl alcohol; The dispersant is polyacrylic acid.

4. The preparation method according to claim 1, characterized in that, The preparation method of the large-particle-size mixture includes: The first step: Mix the large-particle-size zinc oxide elemental powder and bismuth stannate powder to obtain a first-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 200 - 300 rpm and a time of 1 - 3 h; The second step: Heat-treat the first-stage mixture. The heat-treatment temperature is 500 - 700 °C, and the heat-treatment time is 30 - 60 min; The third step: Disperse and screen the heat-treated first-stage mixture to obtain a large-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 200 - 400 nm.

5. The preparation method according to claim 1, characterized in that, The preparation method of the small-particle-size mixture includes: The first step: Mix nickel monoxide, manganese tetroxide, cobalt tetroxide, boron trioxide, and bismuth trioxide to obtain an oxide mixture. The mixing method is dry high-energy ball milling, with a rotation speed of 300 - 500 rpm and a time of 1 - 3 h; The second step: Mix the oxide mixture, nano-tin powder, small-particle-size zinc oxide elemental powder, and nano-silver powder to obtain a second-stage mixture. The mixing method is dry horizontal ball milling, with a rotation speed of 200 - 300 rpm and a time of 2 - 3 h; The third step: Vacuum heat-treat the second-stage mixture. The heat-treatment temperature is 240 - 260 °C, and the heat-treatment time is 30 - 60 min; The fourth step: Disperse and screen the vacuum heat-treated second-stage mixture to obtain a small-particle-size mixture. The dispersion method is jet milling, and the powder particle size is 70 - 150 nm.

6. The preparation method according to claim 1, wherein The preparation method of the dry-pressed powder includes: The first step: Dissolve the binder and dispersant in deionized water, and fully stir to obtain a glue solution. The stirring method is mechanical stirring, with a rotation speed of 300 - 500 rpm and a time of 30 - 60 min; Step 2: Wet ball-mill and sieve the large-particle-size mixture, small-particle-size mixture, and glue solution to obtain granulation slurry. The ball-milling time is 20 - 30 h, the rotation speed is 100 - 300 rpm, and the mesh number of the sieve is 120 - 200 meshes. Step 3: Use a spray dryer to perform spray granulation on the granulation slurry to obtain dry-pressed powder. The spray granulation temperature is 150 - 180 °C.

7. The preparation method according to claim 1, characterized in that, The preparation method of the green compact includes: Use a dry press to perform tabletting on the dry-pressed powder to obtain a green compact. During the dry pressing process, heat the tabletting die simultaneously. The heating temperature is 180 - 220 °C, the dry pressing pressure is 200 - 300 Mpa, and the pressure holding time is 1 - 5 min.

8. The preparation method according to claim 7, characterized in that, The density of the green compact is 4.13 - 4.82 g / cm3.

9. The preparation method according to claim 1, characterized in that, The preparation method of the sintering includes: Step 1: Perform debinding on the green compact. The debinding temperature is 450 - 550 °C, the atmosphere is air, and the debinding time is 60 - 90 min. Step 2: Perform sintering on the debound green compact to obtain a resistor chip blank. The sintering temperature is 900 - 1000 °C, and the sintering time is 1 - 3 h. Step 3: Grind and clean the resistor chip blank, and then prepare silver electrodes on the surface of the treated resistor chip blank to obtain a finished zinc oxide resistor. The silver electrode preparation method is screen printing. The thickness of the silver electrode is 50 - 150 um, and the silver electrode sintering temperature is 600 - 650 °C.

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