Preparation method of ultrahigh gradient zinc oxide varistor
By optimizing the components and processes of zinc oxide resistor plates, the potential gradient and flow capacity are improved, and the problem of insufficient protection capability of traditional resistor plates in high voltage environments is solved, thereby achieving efficient overvoltage protection in miniaturized equipment.
Patent Information
- Application Number
- CN202411486226.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-23
- Publication Date
- 2025-01-03
AI Technical Summary
Traditional zinc oxide resistors are difficult to meet the needs of overvoltage protection in high voltage environments, especially in miniaturized equipment, which leads to increased equipment footprint and increased cost.
Using a preparation method of ultra-high gradient zinc oxide varistor plate, the ball milling, mixing, tableting, glueing, sintering and other components of ZnO and rare earth oxides and niobium oxides, and sintering them, and the resistor plate is Surface coated electrodes, optimize grain boundary characteristics and nonlinear coefficients, and improve potential gradient.
It realizes overvoltage protection that provides high potential gradient and flow capacity in a limited space, meets the application needs of high voltage equipment, and reduces the volume and cost of equipment.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of resistor sheets, and in particular to a method for preparing an ultra-high gradient zinc oxide varistor sheet. Background Art
[0002] With the rapid development of modern power systems, electronic equipment and other fields, higher and higher requirements are placed on overvoltage protection components. Zinc oxide materials have great potential in overvoltage protection due to their unique electrical properties. Although early zinc oxide resistors have certain varistor characteristics, they have limitations in key performance such as potential gradient. Traditional zinc oxide resistors are gradually unable to meet the requirements in the face of the growing demand for high voltage and miniaturized equipment protection. For example, in high-voltage power systems, traditional resistors may require a larger volume to achieve effective overvoltage protection, which not only increases the footprint and cost of the equipment, but may also affect the layout flexibility of the power system. With the trend of miniaturization of electronic equipment, traditional resistors cannot provide sufficient overvoltage protection capabilities in a limited space due to insufficient potential gradients. Therefore, it is necessary to prepare a high-gradient zinc oxide varistor to meet its application requirements in high-voltage and other equipment. Summary of the invention
[0003] The invention provides a method for preparing an ultra-high gradient zinc oxide varistor sheet, which solves the problem of low potential gradient of the zinc oxide varistor sheet in the related art.
[0004] The technical solution of the present invention is as follows: The present invention provides a method for preparing an ultra-high gradient zinc oxide varistor sheet, comprising the following steps: S1, after ball milling the raw materials, adding a binder and mixing, to obtain a granular material; S2, pressing, debinding and sintering the granular materials in sequence to obtain a rough resistor blank; S3, coating electrodes on the surface of the resistor blank to obtain a zinc oxide varistor; The raw materials include the following components in parts by weight: 85-90 parts of ZnO, 1-3 parts of Co3O4, 2-5 parts of Bi2O3, 0.5-1.5 parts of NiO, 0.8-1.2 parts of MnO2, 0.5-1 parts of SiO2, 0.2-0.8 parts of MgO, 0.3-0.7 parts of ZrO2, 3-6 parts of Sb(OH)3, and 0.01-0.5 parts of rare earth oxides, wherein the rare earth oxides include one or more of lanthanum oxide, neodymium oxide, and europium oxide.
[0005] As a further technical solution, the weight percentage of the rare earth oxide is 0.1~0.3.
[0006] As a further technical solution, the rare earth oxides are lanthanum oxide and neodymium oxide.
[0007] In the present invention, the potential gradient of the zinc oxide varistor sheet is further improved by limiting the rare earth oxides to lanthanum oxide and neodymium oxide.
[0008] As a further technical solution, the mass ratio of the lanthanum oxide to the neodymium oxide is 2~4:1.
[0009] As a further technical solution, the binder is a polyvinyl alcohol aqueous solution.
[0010] As a further technical solution, the mass concentration of the polyvinyl alcohol aqueous solution is 4% to 6%.
[0011] As a further technical solution, the raw material also includes 0.02-0.08 parts of niobium oxide.
[0012] In the present invention, by adding niobium oxide into the raw materials, the potential gradient and the current carrying capacity of the zinc oxide varistor sheet are further improved.
[0013] As a further technical solution, the niobium oxide includes niobium monoxide and niobium dioxide, and the mass ratio of the niobium monoxide to the niobium dioxide is 3-4:1.
[0014] In the present invention, by limiting the niobium oxide to niobium monoxide and niobium dioxide, and limiting the mass ratio of niobium monoxide to niobium dioxide to 3-4:1, the potential gradient and the current carrying capacity of the zinc oxide varistor sheet are further improved.
[0015] As a further technical solution, the tabletting pressure is 80-100 MPa.
[0016] As a further technical solution, the debinding temperature is 350-450° C., and the debinding time is 2-3 hours.
[0017] As a further technical solution, the sintering temperature is 1100-1200° C., and the sintering time is 2-3 hours.
[0018] As a further technical solution, the method for coating the electrode is arc spraying aluminum.
[0019] The working principle and beneficial effects of the present invention are: In the present invention, ZnO is mainly used as the raw material, and appropriate amounts of Co3O4, Bi2O3, NiO, MnO2, SiO2, MgO, ZrO2, Sb(OH)3 and specific rare earth oxides are added. After ball milling, mixing, tableting, debinding, sintering and electrode coating and other process steps, the grain boundary characteristics of zinc oxide are improved, the nonlinear coefficient of the resistor is increased, and the resistor has an ultra-high potential gradient. DETAILED DESCRIPTION
[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0021] In the following examples and comparative examples, polyvinyl alcohol, model: 420H.
[0022] Example 1 A method for preparing an ultra-high gradient zinc oxide varistor sheet comprises the following steps: S1. After ball-milling 85 parts of ZnO, 1 part of Co3O4, 2 parts of Bi2O3, 0.5 parts of NiO, 0.8 parts of MnO2, 0.5 parts of SiO2, 0.2 parts of MgO, 0.3 parts of ZrO2, 3 parts of Sb(OH)3, and 0.01 parts of rare earth oxide, 4 wt% polyvinyl alcohol aqueous solution was added and mixed to obtain a granular material; the rare earth oxide is neodymium oxide; S2, the granular material is pressed into sheets at 80 MPa, the binder is removed at 350°C for 3 hours, the temperature is raised to 1100°C, the sintering time is 3 hours, and the rough blank of the resistor is obtained after cooling in the furnace; S3, coating electrodes on the surface of the resistor blank by arc spraying aluminum to obtain a zinc oxide varistor.
[0023] Example 2 A method for preparing an ultra-high gradient zinc oxide varistor sheet comprises the following steps: S1. After ball-milling 87 parts of ZnO, 2 parts of Co3O4, 3 parts of Bi2O3, 1 part of NiO, 1 part of MnO2, 0.7 parts of SiO2, 0.5 parts of MgO, 0.5 parts of ZrO2, 4 parts of Sb(OH)3, and 0.01 parts of rare earth oxide, 5 wt% polyvinyl alcohol aqueous solution was added and mixed to obtain a granular material; the rare earth oxide is lanthanum oxide; S2, the granular material is pressed into sheets at 90 MPa, the binder is removed at 400°C for 2 hours, the temperature is raised to 1150°C, the sintering time is 3 hours, and the rough blank of the resistor is obtained after cooling in the furnace; S3, coating electrodes on the surface of the resistor blank by arc spraying aluminum to obtain a zinc oxide varistor.
[0024] Example 3 A method for preparing an ultra-high gradient zinc oxide varistor sheet comprises the following steps: S1. After ball-milling 90 parts of ZnO, 3 parts of Co3O4, 5 parts of Bi2O3, 1.5 parts of NiO, 1.2 parts of MnO2, 1 part of SiO2, 0.8 parts of MgO, 0.7 parts of ZrO2, 6 parts of Sb(OH)3, and 0.1 parts of rare earth oxide, 6 wt% polyvinyl alcohol aqueous solution was added and mixed to obtain a granular material; the rare earth oxide is europium oxide; S2, the granular material is pressed into sheets at 100 MPa, the binder is removed at 450°C for 2 hours, the temperature is raised to 1200°C, the sintering time is 2 hours, and the rough blank of the resistor is obtained after cooling in the furnace; S3, coating electrodes on the surface of the resistor blank by arc spraying aluminum to obtain a zinc oxide varistor.
[0025] Example 4 The only difference between this embodiment and embodiment 1 is that the added amount of rare earth oxide is 0.1 parts.
[0026] Example 5 The only difference between this embodiment and embodiment 1 is that the added amount of rare earth oxide is 0.3 parts.
[0027] Example 6 The only difference between this embodiment and embodiment 5 is that the rare earth oxide is lanthanum oxide.
[0028] Example 7 The only difference between this embodiment and Embodiment 5 is that the rare earth oxide consists of lanthanum oxide and neodymium oxide in a mass ratio of 1:1.
[0029] Example 8 The only difference between this embodiment and Embodiment 5 is that the rare earth oxide consists of lanthanum oxide and neodymium oxide in a mass ratio of 5:1.
[0030] Example 9 The only difference between this embodiment and embodiment 5 is that the rare earth oxide consists of lanthanum oxide and neodymium oxide in a mass ratio of 2:1.
[0031] Example 10 The only difference between this embodiment and embodiment 5 is that the rare earth oxide consists of lanthanum oxide and neodymium oxide in a mass ratio of 4:1.
[0032] Embodiment 11 The only difference between this embodiment and embodiment 10 is that 0.02 parts of niobium oxide is added before ball milling in step S1; the niobium oxide is niobium dioxide.
[0033] Example 12 The only difference between this embodiment and embodiment 10 is that 0.08 parts of niobium oxide is added before ball milling in step S1; the niobium oxide is niobium dioxide.
[0034] Embodiment 13 The only difference between this embodiment and Embodiment 11 is that the niobium oxide is niobium monoxide.
[0035] Embodiment 14 The only difference between this embodiment and Embodiment 11 is that the niobium oxide consists of niobium monoxide and niobium dioxide in a mass ratio of 3:1.
[0036] Embodiment 15 The only difference between this embodiment and Embodiment 11 is that the niobium oxide consists of niobium monoxide and niobium dioxide in a mass ratio of 4:1.
[0037] Comparative Example 1 The only difference between this embodiment and embodiment 1 is that the rare earth oxide is replaced by an equal amount of gallium oxide.
[0038] Comparative Example 2 The only difference between this embodiment and embodiment 1 is that neodymium oxide is replaced by an equal amount of cerium oxide.
[0039] The zinc oxide varistors prepared in Examples 1 to 15 and Comparative Examples 1 to 2 were respectively tested for potential gradient and current carrying capacity. The test results are shown in Table 1.
[0040] Table 1 Performance test results of zinc oxide varistor
[0041] Compared with Example 1, Comparative Example 1 did not add rare earth oxide, while Comparative Example 2 added rare earth oxide cerium oxide. As a result, the potential gradient and current carrying capacity of the resistors in Comparative Examples 1~2 were lower than those in Example 1, indicating that adding rare earth oxide neodymium oxide to the resistor can improve the potential gradient and current carrying capacity of the resistor.
[0042] Compared with Example 1, the amount of neodymium oxide added was changed in Examples 4-5. As a result, the potential gradient of the resistor in Examples 4-5 was higher than that in Example 1, indicating that when the amount of neodymium oxide added was 0.1-0.3 parts, the potential gradient of the resistor could be further improved.
[0043] Compared with Example 5, the composition of the rare earth oxides was changed in Examples 6 to 10. As a result, the potential gradient and the current carrying capacity of the resistor in Examples 9 to 10 were higher than those in Examples 5 to 8, indicating that when the rare earth oxides are composed of lanthanum oxide and neodymium oxide, and the mass ratio of lanthanum oxide to neodymium oxide is 2 to 4:1, the potential gradient and the current carrying capacity of the resistor can be further improved.
[0044] Compared with Example 10, niobium oxide was added in Examples 11 to 15. As a result, the potential gradient and current carrying capacity of the resistor in Examples 14 to 15 were higher than those in Examples 10 to 13, indicating that when niobium monoxide and niobium dioxide were added at the same time, and the mass ratio of niobium monoxide to niobium dioxide was 3 to 4:1, the potential gradient and current carrying capacity of the resistor could be further improved.
[0045] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing an ultra-high gradient zinc oxide varistor sheet, characterized in that: The following steps are involved: S1, after ball milling the raw materials, adding a binder and mixing, to obtain a granular material; S2, pressing, debinding and sintering the granular materials in sequence to obtain a rough resistor blank; S3, coating electrodes on the surface of the resistor blank to obtain a zinc oxide varistor; The raw materials include the following components in parts by weight: 85-90 parts of ZnO, 1-3 parts of Co3O4, 2-5 parts of Bi2O3, 0.5-1.5 parts of NiO, 0.8-1.2 parts of MnO2, 0.5-1 parts of SiO2, 0.2-0.8 parts of MgO, 0.3-0.7 parts of ZrO2, 3-6 parts of Sb(OH)3, and 0.01-0.5 parts of rare earth oxides, wherein the rare earth oxides include one or more of lanthanum oxide, neodymium oxide, and europium oxide.
2. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 1, characterized in that: The weight percentage of the rare earth oxide is 0.1-0.
3.
3. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 1, characterized in that: The rare earth oxides are lanthanum oxide and neodymium oxide.
4. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 3, characterized in that: The mass ratio of the lanthanum oxide to the neodymium oxide is 2-4:
1.
5. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 1, characterized in that: The binder is a polyvinyl alcohol aqueous solution.
6. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 5, characterized in that: The mass concentration of the polyvinyl alcohol aqueous solution is 4% to 6%.
7. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 1, characterized in that: The raw material also includes 0.02-0.08 parts of niobium oxide.
8. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 7, characterized in that: The niobium oxide includes niobium monoxide and niobium dioxide, and the mass ratio of the niobium monoxide to the niobium dioxide is 3-4:
1.
9. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 1, characterized in that: The sintering temperature is 1100-1200° C., and the sintering time is 2-3 hours.
10. The method for preparing an ultra-high gradient zinc oxide varistor sheet according to claim 1, characterized in that: The method of coating the electrode is arc spraying aluminum.