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CN-122000156-A - Zinc oxide resistor disc and preparation method and application thereof

CN122000156ACN 122000156 ACN122000156 ACN 122000156ACN-122000156-A

Abstract

The invention belongs to the technical field of high-voltage electrical material preparation, and particularly relates to a zinc oxide resistor disc, a preparation method and application thereof. The preparation method comprises the steps of (1) pre-sintering zinc oxide powder, (2) mixing the zinc oxide powder obtained in the step (1), an auxiliary agent and a dispersion liquid, ball-milling to obtain slurry, wherein the particle size D50 of the slurry is 0.8-1.2 mu m, the dispersity is more than or equal to 95%, spray-drying and granulating the slurry to obtain granulated powder, (4) forming and first sintering the granulated powder to obtain a semi-finished product of the resistor disc, wherein the first sintering adopts sectional sintering, and (5) forming an electrode layer on at least one surface of the semi-finished product of the resistor disc by adopting a vacuum sputtering and/or electrophoretic deposition process, and performing second sintering and annealing. The contact resistance of the zinc oxide resistor disc is less than or equal to 5mΩ, the leakage current is less than or equal to 2 mu A after aging for 1000 hours in an environment of 85 ℃ and 85% RH, and the performance attenuation rate is less than or equal to 5%.

Inventors

  • XIE PENGKANG
  • NING KAI
  • WANG HAINING
  • FU ZHIYAO

Assignees

  • 国网湖南省电力有限公司防灾减灾中心
  • 国网湖南省电力有限公司
  • 国家电网有限公司

Dates

Publication Date
20260508
Application Date
20260130

Claims (10)

  1. 1. The preparation method of the zinc oxide resistor disc is characterized by comprising the following steps of: (1) Presintering zinc oxide powder; (2) Mixing the zinc oxide powder obtained in the step (1), an auxiliary agent and a dispersion liquid, and ball-milling to obtain slurry, wherein the median particle diameter D50 of the slurry is 0.8-1.2 mu m, and the dispersity is more than or equal to 95%; (3) Spray drying and granulating the slurry to obtain granulated powder; (4) The granulated powder is molded and subjected to first sintering to obtain a semi-finished product of the resistor disc, wherein the first sintering adopts sectional sintering; (5) And forming an electrode layer on at least one surface of the semi-finished product of the resistor disc by adopting a vacuum sputtering and/or electrophoretic deposition process, and performing second sintering and annealing.
  2. 2. The method of claim 1, wherein the pre-sintering is performed at a temperature of 850 ℃ to 900 ℃ for a time of 1.5h to 2h in step (1); Preferably, the specific step of pre-sintering comprises the steps of heating to 850-900 ℃ at a heating rate of 8-10 ℃ per minute and then preserving heat for 1.5-2 h.
  3. 3. The production method according to claim 1 or 2, wherein the step (2) satisfies at least one of (1) to (4): (1) The auxiliary agent comprises at least one of Cr 2 O 3 、SiO 2 、Bi 2 O 3 、Sb 2 O 3 、CoO、MnO、Al 2 O 3 ; Preferably, the auxiliary agent comprises Cr 2 O 3 、SiO 2 、Bi 2 O 3 、Sb 2 O 3 、CoO、MnO、Al 2 O 3 ; More preferably, the content of Bi 2 O 3 is 1.5wt% to 3.0wt%, the content of Sb 2 O 3 is 1.0wt% to 2.0wt%, the content of CoO is 0.5wt% to 1.0wt%, the content of MnO is 0.3wt% to 0.8wt%, the content of Cr 2 O 3 is 0.2wt% to 0.5wt%, the content of SiO 2 is 0.1wt% to 0.3wt%, and the content of Al 2 O 3 is 0.05wt% to 0.15wt%, based on 100wt% of the total mass of the zinc oxide powder and the auxiliary agent; (2) The dispersion liquid is a dispersion liquid containing TiO 2 ; Preferably, the dispersion comprises organosilane coated TiO 2 particles; More preferably, the organosilane coated TiO 2 particles have a median particle diameter D50 of 20nm to 50nm; (3) The ratio of the total mass of the zinc oxide powder and the auxiliary agent to the mass of the organosilane coated TiO 2 in the dispersion is (10-15) 1; (4) The ball milling comprises primary ball milling and secondary ball milling; Preferably, the first-stage ball milling parameters comprise the steps of adopting planetary ball milling, wherein the ball-material ratio is 4-5:1, the rotating speed is 200rpm-250rpm, and the time is 5-6 h; Preferably, the parameters of the secondary ball milling comprise the adoption of ultrasonic ball milling, the ball milling ratio is 2-3:1, the rotating speed is 150rpm-250rpm, the ultrasonic power is 400W-450W, and the time is 1h-1.5h.
  4. 4. A method according to any one of claims 1 to 3, wherein the granulated powder has a flowability of not less than 20s/100mL and a bulk density of 1.2g/cm 3 -1.4g/cm 3 ; And/or, the mass ratio of the particles with the mesh number of 40-60 meshes in the granulating powder is more than or equal to 95wt%; And/or the spray drying inlet temperature is 200 ℃ to 220 ℃ and the spray drying outlet temperature is 80 ℃ to 90 ℃.
  5. 5. The method according to any one of claims 1 to 4, wherein the molding is performed at a pressure of 25MPa to 30MPa for a time of 8min to 10min; And/or drying the rough blank obtained after the molding at 100-120 ℃ for 2-3 hours to obtain a blank, wherein the density of the blank is preferably more than or equal to 3.2g/cm 3 .
  6. 6. The method according to any one of claims 1 to 5, wherein in the step (5), the ZnO crystal grains in the semi-finished resistive sheet have a particle size of 5 μm to 8 μm and the grain boundary layer has a thickness of 10nm to 15nm; and/or the specific steps of the sectional sintering comprise the steps of heating from room temperature to 300-350 ℃ at a heating rate of 8-10 ℃ per minute, then preserving heat for 15-20min, heating to 600-650 ℃ at a heating rate of 3-5 ℃ per minute, then preserving heat for 30-35min, heating to 1100-1150 ℃ at a heating rate of 2-3 ℃ per minute, preserving heat for 35-40min, heating to 1150-1180 ℃ at a heating rate of 1-1.2 ℃ per minute, preserving heat for 60-80min, cooling to 600-800 ℃ at a cooling rate of 4-5 ℃ per minute, preserving heat for 25-30min, and finally cooling to room temperature along with a furnace.
  7. 7. The method of any one of claims 1-6, wherein the electrode layer comprises a first film layer and a second film layer; preferably, the thickness of the first film layer is 50nm-80nm; Preferably, the thickness of the second film layer is 5-8 μm; preferably, the material of the electrode layer includes at least one of silver and aluminum.
  8. 8. The method according to any one of claims 1 to 7, wherein the second sintering is performed at a temperature of not higher than 10 ℃ per minute, at a temperature of 250 ℃ to 300 ℃ for a time of 1h to 1.5h; And/or the temperature rising speed of the annealing is not higher than 20 ℃ per minute, the temperature is 280-300 ℃ and the time is 1-1.5 h.
  9. 9. A zinc oxide resistor sheet produced by the production method according to any one of claims 1 to 8.
  10. 10. Use of a zinc oxide resistor disc produced by the production method according to any one of claims 1 to 8 or a zinc oxide resistor disc according to claim 9 in a lightning arrester and/or surge protector.

Description

Zinc oxide resistor disc and preparation method and application thereof Technical Field The invention belongs to the technical field of high-voltage electrical material preparation, and particularly relates to a zinc oxide resistor disc, a preparation method and application thereof. Background The zinc oxide resistor disc is used as a core element for overvoltage protection of a high-voltage power system, and the performance of the zinc oxide resistor disc depends on a ZnO grain-grain boundary microstructure, so that the voltage-sensitive voltage fluctuation is less than or equal to +/-5%, the 25 ℃ leakage current is less than or equal to 10 mu A (under 1.05 times of voltage-sensitive voltage), and the 4/10 mu s lightning current capacity is more than or equal to 60kA. The existing zinc oxide resistor disc preparation process has the industrial bottleneck that 1) the performance fluctuation caused by uneven raw material dispersion is that the problem of agglomeration of doping agents such as Bi 2O3、Sb2O3 and the like cannot be solved by the traditional dry ball milling or single-stage wet ball milling, the pressure-sensitive voltage fluctuation of a finished product is more than +/-8%, and the batch qualification rate is less than or equal to 90%. 2) The uncontrolled sintering process affects the microstructure, namely, intermittent kiln constant temperature sintering is easy to generate low-temperature sintering, which leads to incomplete decomposition of organic matters, abnormal growth (more than or equal to 15 mu m) of crystal grains, leakage current is more than or equal to 20 mu A, through-flow capacity is less than or equal to 45kA, and the performance requirement of the zinc oxide resistor disc cannot be met. 3) The electrode has high preparation cost and poor adhesive force, the silver consumption of the silver paste printing-high temperature sintering process is more than or equal to 5 g/piece, the cost is 30 percent, the cost is increased, meanwhile, the difference of the thermal expansion coefficients of the silver layer and the ceramic matrix is large, the adhesive force is less than or equal to 3MPa, and the silver paste is easy to fall off after long-term operation. 4) The industrialization suitability is insufficient, the existing technology is used for focusing laboratory small-batch preparation (single time is less than or equal to 100 tablets), the molding depends on manual dry pressing (the fluctuation of the green body density is +/-3%), the sintering period is more than or equal to 24 hours per batch, and the large-scale modulus production requirement cannot be met. Disclosure of Invention In order to solve the technical problems, the invention provides a zinc oxide resistor disc, and a preparation method and application thereof. In a first aspect, the present invention provides a method for preparing a zinc oxide resistor sheet, comprising the steps of: (1) Presintering zinc oxide powder; (2) Mixing the zinc oxide powder obtained in the step (1), an auxiliary agent and a dispersion liquid, and ball-milling to obtain slurry, wherein the median particle diameter D50 of the slurry is 0.8-1.2 mu m, and the dispersity is more than or equal to 95%; (3) Spray drying and granulating the slurry to obtain granulated powder; (4) The granulated powder is molded and subjected to first sintering to obtain a semi-finished product of the resistor disc, wherein the first sintering adopts sectional sintering; (5) And forming an electrode layer on at least one surface of the semi-finished product of the resistor disc by adopting a vacuum sputtering and/or electrophoretic deposition process, and performing second sintering and annealing. Exemplary particle sizes D50 of the slurry are 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, or in a range consisting of any two of the above values. As an alternative embodiment, in the step (1), the pre-sintering temperature is 850 ℃ to 900 ℃ and the time is 1.5h to 2h; Preferably, the specific step of pre-sintering comprises the steps of heating to 850-900 ℃ at a heating rate of 8-10 ℃ per minute and then preserving heat for 1.5-2 h. Exemplary pre-sintering temperatures are 850 ℃, 860 ℃, 870 ℃, 880 ℃, 890 ℃, 900 ℃, or within a range consisting of any two of the above. As an alternative embodiment, the step (2) satisfies at least one of (1) - (4): (1) The auxiliary agent comprises at least one of Cr2O3、SiO2、Bi2O3、Sb2O3、CoO、MnO、Al2O3; Preferably, the auxiliary agent comprises Cr2O3、SiO2、Bi2O3、Sb2O3、CoO、MnO、Al2O3; More preferably, the content of Bi 2O3 is 1.5wt% to 3.0wt%, the content of Sb 2O3 is 1.0wt% to 2.0wt%, the content of CoO is 0.5wt% to 1.0wt%, the content of MnO is 0.3wt% to 0.8wt%, the content of Cr 2O3 is 0.2wt% to 0.5wt%, the content of SiO 2 is 0.1wt% to 0.3wt%, and the content of Al 2O3 is 0.05wt% to 0.15wt%, based on 100wt% of the total mass of the zinc oxide powder and the auxiliary agent; (2) The dispersion liquid is a dispersion liquid containing TiO 2; Prefe