A low-gradient resistor chip for a lightning arrester monitor and its preparation method

Abstract

The present invention relates to the technical field of varistors for lightning arresters, and provides a low-gradient varistor for lightning arrester monitors, which comprises the following raw materials in parts by weight: 85-90 parts of zinc oxide, 1.2-3.6 parts of sintering promoter; the sintering promoter comprises one or more of special low-temperature glass, boric acid, and titanium dioxide. Through the above technical solution, the problems of high lightning wave residual voltage and low charge transfer performance of low-gradient varistors in the related art are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of resistor chips, and specifically, to a low-gradient resistor chip for an arrester monitor and a preparation method thereof. Background Art

[0002] The resistor chip for an arrester monitor is an important component used in an arrester monitor. The resistor chips for an arrester detector can be classified into high-gradient resistor chips, medium-gradient resistor chips, and low-gradient resistor chips according to the gradient. The low-gradient resistor chip generates a relatively low voltage per unit thickness, and can effectively limit the overvoltage at a relatively low voltage. Due to its good non-linear characteristics and high stability, it is widely used in power systems, industrial fields, and rail transit. However, the currently used low-gradient resistor chips generally have problems such as large lightning wave residual voltage, low charge transfer performance, large diameter of the resistor chip, which is not conducive to the miniaturization and installation of the detector. Excessive lightning wave residual voltage will not only cause the protected electrical equipment to bear too high a voltage, resulting in damage and breakdown of the equipment insulation, but also affect the system stability, leading to problems such as system voltage fluctuation and tripping, affecting the power supply quality and reliability, and reducing the protection effect of the arrester. Too low charge transfer performance means that the resistor chip cannot quickly transfer the charge generated by the lightning shock in a short time, resulting in the overvoltage not being released in time, reducing the overvoltage protection ability of the arrester, increasing the risk of equipment damage, and affecting the reliability of the system. Therefore, developing a low-gradient resistor chip with low lightning wave residual voltage and high charge transfer performance is an urgent problem to be solved at present. Summary of the Invention

[0003] The present invention provides a low-gradient resistor chip for an arrester monitor and a preparation method thereof, which solves the problems of high lightning wave residual voltage and low charge transfer performance of the low-gradient resistor chip in the related art.

[0004] The technical solution of the present invention is as follows: The present invention provides a low-gradient resistor chip for an arrester monitor, which comprises the following raw materials in parts by weight: 85-90 parts of zinc oxide, 1.2-3.6 parts of a sintering promoter;

[0005] The sintering promoter includes one or more of special low-temperature glass, boric acid, and titanium dioxide.

[0006] As a further technical solution, the bulk density of the special low-temperature glass is 0.61-0.81 g / cm 3 .

[0007] In the present invention, the special low-temperature glass with a bulk density of 0.61-0.81 g / cm 3As one of the raw materials of the special low-temperature glass used as a sintering promoter, it helps the resistors to be filled and distributed more evenly during the production process, ensuring the consistency of the microstructure of the resistors, optimizing the sintering process, making the sintering more complete and uniform, thereby improving the electrical performance of the resistors and obtaining resistors with low lightning wave residual voltage and high charge transfer performance.

[0008] As a further technical solution, when the sintering promoter is composed of special low-temperature glass, boric acid, and titanium dioxide, the mass ratio of the special low-temperature glass to boric acid and titanium dioxide is 2-4:1:1.

[0009] In the present invention, by adjusting the ratio between the sintering promoters, the respective advantages of these three substances are fully utilized, enabling them to have a synergistic effect in improving the performance of the resistors, effectively reducing the lightning wave residual voltage, enhancing the charge transfer performance, and strengthening the overall performance of the resistors.

[0010] As a further technical solution, the mass ratio of the special low-temperature glass, boric acid, and titanium dioxide is 3:1:1.

[0011] As a further technical solution, it also includes the following raw material components in parts by weight: 1-3 parts of an additive, and the additive includes one or more of cobalt trioxide, manganese carbonate, antimony trioxide, and chromium trioxide.

[0012] As a further technical solution, it also includes the following raw material components in parts by weight: 1-6 parts of a flux, and the flux includes one or more of oxalic acid, acetic acid, and citric acid.

[0013] As a further technical solution, it also includes the following raw material components in parts by weight: 2-8 parts of a uniformity aid, and the uniformity aid includes one or more of zinc hydroxide, cobalt hydroxide, and nickel hydroxide.

[0014] As a further technical solution, it also includes the following raw material components in parts by weight: 7-10 parts of bismuth-based low-temperature lead-free glass frit, and the bismuth-based low-temperature lead-free glass frit is composed of the following raw materials in parts by weight: 4.5-5 parts of bismuth oxide, 0.5-1 part of silicon dioxide, 0.5-0.8 part of boron trioxide, 0.3-0.5 part of aluminum oxide, 0.6-0.8 part of calcium oxide, 0.5-1 part of lithium oxide, and 0.5-0.8 part of potassium oxide.

[0015] As a further technical solution, the preparation method of the bismuth-based low-temperature lead-free glass frit includes the following steps: mixing the raw materials of the bismuth-based low-temperature lead-free glass frit, melting, cooling, and pulverizing to obtain the bismuth-based low-temperature lead-free glass frit.

[0016] As a further technical solution, the particle size D50 of the bismuth-based low-temperature lead-free glass frit obtained after pulverization is 1 μm - 3 μm.

[0017] The present invention also provides a preparation method for a low-gradient resistor chip for an arrester monitor, comprising the following steps:

[0018] S1. Weigh the zinc oxide sintering promoter in the said parts by weight, mix, granulate, and then obtain a green body of the resistor chip by die pressing.

[0019] S2. The green body of the resistor chip is dried, calcined, and degummed to obtain a pre-sintered body of the resistor chip.

[0020] S3. Spray the end face of the pre-sintered body of the resistor chip with aluminum and coat the side face with a bismuth-based low-temperature lead-free glass glaze, and then obtain the low-gradient resistor chip after sintering.

[0021] As a further technical solution, the temperature of degumming is 300-400°C, the time of degumming is 1-3 h, and the temperature of sintering is 1200-1300°C.

[0022] The working principle and beneficial effects of the present invention are as follows:

[0023] In the present invention, using special low-temperature glass, boric acid, and titanium dioxide as the sintering promoter can not only promote the good growth and uniform distribution of zinc oxide grains, form a dense microstructure, adjust the electrical performance parameters of the resistor chip, enable the resistor chip as a whole to better withstand lightning strikes, reduce the lightning residual voltage value, but also improve the internal conductive channels of the resistor chip, improve the efficiency of charge transfer, avoid local charge accumulation, and improve the response speed and charge transfer performance of the resistor chip. Specific Embodiments

[0024] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts fall within the scope of the present invention.

[0025] Embodiment 1

[0026] Bismuth-based low-temperature lead-free glass glaze powder: Weigh 4.5 parts of bismuth oxide, 0.5 parts of silicon dioxide, 0.5 parts of boron trioxide, 0.3 parts of aluminum oxide, 0.6 parts of calcium oxide, 0.5 parts of lithium oxide, and 0.5 parts of potassium oxide, mix evenly, melt at 800°C, pour into water and cool quickly to form glass slag, and obtain bismuth-based low-temperature lead-free glass glaze powder with a particle size D50 of 1 μm through ball milling and screening.

[0027] A preparation method for a low-gradient resistor chip for an arrester monitor, comprising the following steps:

[0028] S1. Weigh 85 parts of zinc oxide, 1 part of cobalt sesquioxide, 1.2 parts of special low-temperature glass (bulk density is 0.57 g / cm 3 , model D270, initial melting temperature 700 °C, linear expansion coefficient 90×10 -7 , manufactured by Anmi Micro-Nano New Materials Co., Ltd.), 1 part of oxalic acid, and 2 parts of zinc hydroxide. Mix, dry, granulate, and obtain a green compact of the resistor chip after molding;

[0029] S2. After drying the green compact of the resistor chip, place it in a calcination and debinding chamber, with a heating rate of 3 °C / min. Heat up to 300 °C, start calcination and debinding, keep it warm for 1 h, and cool to room temperature to obtain a pre-sintered body of the resistor chip;

[0030] S3. Use an automatic aluminum spraying machine to spray the end face of the pre-sintered body of the resistor chip with full electrodes, and coat the side with bismuth-based low-temperature lead-free glass glaze. Sinter at 1200 °C for 30 min to obtain a low-gradient resistor chip. The gradient of the resistor chip is 25 V / mm, the thickness is 8 mm, and the diameter is 60 mm.

[0031] Example 2

[0032] Bismuth-based low-temperature lead-free glass glaze powder: Weigh 4.8 parts of bismuth oxide, 0.8 parts of silicon dioxide, 0.6 parts of boron sesquioxide, 0.4 parts of alumina, 0.7 parts of calcium oxide, 0.8 parts of lithium oxide, and 0.6 parts of potassium oxide. Mix evenly, melt at 850 °C, pour into water and cool quickly to form glass slag, and obtain bismuth-based low-temperature lead-free glass glaze powder with a D50 particle size of 2 μm through ball milling and screening.

[0033] A preparation method of a low-gradient resistor chip for a lightning arrester monitor, comprising the following steps:

[0034] S1. Weigh 88 parts of zinc oxide, 2 parts of manganese carbonate, 2.4 parts of special low-temperature glass (bulk density is 0.57 g / cm 3 , model D270, initial melting temperature 700 °C, linear expansion coefficient 90×10 -7 , manufactured by Anmi Micro-Nano New Materials Co., Ltd.), 3 parts of acetic acid, and 5 parts of cobalt hydroxide. Mix, dry, granulate, and obtain a green compact of the resistor chip after molding;

[0035] S2. After drying the green compact of the resistor chip, place it in a calcination and debinding chamber, with a heating rate of 4 °C / min. Heat up to 350 °C, start calcination and debinding, keep it warm for 2 h, and cool to room temperature to obtain a pre-sintered body of the resistor chip;

[0036] S3. Use an automatic aluminum spraying machine to spray the end face of the pre-sintered body of the resistor chip with full electrodes, and coat the side with bismuth-based low-temperature lead-free glass glaze. Sinter at 1250 °C for 20 min to obtain a low-gradient resistor chip. The gradient of the resistor chip is 25 V / mm, the thickness is 8 mm, and the diameter is 60 mm.

[0037] Example 3

[0038] Bismuth-based low-temperature lead-free glass frit: Weigh 5 parts of bismuth oxide, 5 parts of silicon dioxide, 0.8 part of boron trioxide, 0.5 part of aluminum oxide, 0.5 part of calcium oxide, 5 parts of lithium oxide, and 0.8 part of potassium oxide. After mixing evenly, melt at 900 °C, pour into water and cool rapidly to form glass slag, and obtain bismuth-based low-temperature lead-free glass frit with a particle size D50 of 3 μm through ball milling and screening.

[0039] A preparation method of a low-gradient resistor chip for a lightning arrester monitor includes the following steps:

[0040] S1. Weigh 90 parts of zinc oxide, 3 parts of antimony trioxide, 3.6 parts of special low-temperature glass (bulk density is 0.57 g / cm 3 , model D270, initial melting temperature 700 °C, linear expansion coefficient 90×10 -7 , manufacturer is Anmi Micro-Nano New Materials Co., Ltd.), 6 parts of citric acid, and 8 parts of nickel hydroxide. Mix, dry, granulate, and press to obtain a green body of the resistor chip.

[0041] S2. After drying the green body of the resistor chip, place it in a calcination and debinding chamber, with a heating rate of 5 °C / min, heat up to 400 °C, start calcination and debinding, hold for 3 h, and cool to room temperature to obtain a pre-sintered body of the resistor chip.

[0042] S3. Use an automatic aluminum spraying machine to spray the end face of the pre-sintered body of the resistor chip with full electrodes, coat the side with bismuth-based low-temperature lead-free glass frit, and sinter at 1300 °C for 10 min to obtain a low-gradient resistor chip. The gradient of the resistor chip is 25 V / mm, the thickness is 8 mm, and the diameter is 60 mm.

[0043] Example 4

[0044] Compared with Example 1, the difference in Example 4 is that 1.2 parts of special low-temperature glass (bulk density is 0.57 g / cm 3 , model D270, initial melting temperature 700 °C, linear expansion coefficient 90×10 -7 , manufacturer is Anmi Micro-Nano New Materials Co., Ltd.) are replaced with an equal amount of special low-temperature glass (bulk density is 0.61 g / cm 3 , model D255, initial melting temperature 550 °C, linear expansion coefficient 85×10 -7 , manufacturer is Anmi Micro-Nano New Materials Co., Ltd.).

[0045] Example 5

[0046] Compared with Example 1, the difference in Example 5 is that 1.2 parts of special low-temperature glass (bulk density is 0.57 g / cm 3 , model D270, initial melting temperature 700 °C, linear expansion coefficient 90×10-7 (manufacturer: Anmi Micro-Nano New Materials Co., Ltd.) Replace 1.2 parts with an equal amount of special low-temperature glass (bulk density: 0.75 g / cm 3 , model D245, initial melting temperature: 450 °C, linear expansion coefficient: 90×10 -7 (manufacturer: Anmi Micro-Nano New Materials Co., Ltd.).

[0047] Example 6

[0048] Compared with Example 1, the difference in Example 6 is that 1.2 parts of special low-temperature glass (bulk density: 0.57 g / cm 3 , model D270, initial melting temperature: 700 °C, linear expansion coefficient: 90×10 -7 (manufacturer: Anmi Micro-Nano New Materials Co., Ltd.) are replaced with an equal amount of special low-temperature glass (bulk density: 0.81 g / cm 3 , model D250, initial melting temperature: 500 °C, linear expansion coefficient: 80×10 -7 (manufacturer: Anmi Micro-Nano New Materials Co., Ltd.).

[0049] Example 7

[0050] Compared with Example 1, the difference in Example 7 is that 1.2 parts of special low-temperature glass (bulk density: 0.57 g / cm 3 , model D270, initial melting temperature: 700 °C, linear expansion coefficient: 90×10 -7 (manufacturer: Anmi Micro-Nano New Materials Co., Ltd.) are replaced with an equal amount of special low-temperature glass (bulk density: 1.23 g / cm 3 , model D240, initial melting temperature: 400 °C, linear expansion coefficient: 85×10 -7 (manufacturer: Anmi Micro-Nano New Materials Co., Ltd.).

[0051] Example 8

[0052] Compared with Example 5, the difference in Example 8 is that 1.2 parts of special low-temperature glass are replaced with 0.6 parts of titanium dioxide and 0.6 parts of boric acid.

[0053] Example 9

[0054] Compared with Example 5, the difference in Example 9 is that 1.2 parts of special low-temperature glass are replaced with 0.4 parts of special low-temperature glass, 0.4 parts of boric acid, and 0.4 parts of titanium dioxide.

[0055] Example 10

[0056] Compared with Example 5, Example 10 is different in that 1.2 parts of special low-temperature glass are replaced with 0.6 parts of special low-temperature glass, 0.3 parts of boric acid, and 0.3 parts of titanium dioxide.

[0057] Example 11

[0058] Compared with Example 5, Example 11 is different in that 1.2 parts of special low-temperature glass are replaced with 0.72 parts of special low-temperature glass, 0.24 parts of boric acid, and 0.24 parts of titanium dioxide.

[0059] Example 12

[0060] Compared with Example 5, Example 12 is different in that 1.2 parts of special low-temperature glass are replaced with 0.8 parts of special low-temperature glass, 0.2 parts of boric acid, and 0.2 parts of titanium dioxide.

[0061] Example 13

[0062] Compared with Example 5, Example 13 is different in that 1.2 parts of special low-temperature glass are replaced with 0.9 parts of special low-temperature glass, 0.15 parts of boric acid, and 0.15 parts of titanium dioxide.

[0063] Comparative Example 1

[0064] Compared with Example 1, Comparative Example 1 is different in that no special low-temperature glass is added.

[0065] A low-gradient resistor chip for an arrester monitor prepared in Examples 1 to 13 and Comparative Example 1 was tested according to the following method:

[0066] 1. Residual voltage: According to the test method specified in JB / T 10492-2011 "Testing Devices for Metal Oxide Arresters", the residual voltage of the sample was tested under the test conditions of: two pieces in parallel, 20 kA.

[0067] 2. Charge transfer performance improvement rate: According to the test method of rated repetitive transferred charge specified in GB / T 11032-2020 "AC Non-Clearance Metal Oxide Arresters", the charge transfer performance improvement rate of the sample was tested. The test time was 2 ms, and the charge transfer performance improvement rate = [(transferred charge after improvement - transferred charge before improvement) / transferred charge before improvement] × 100%.

[0068] The test results are shown in the following table:

[0069] Table 1 Performance test results of low-gradient resistor chips for arrester monitors prepared in Examples 1 to 13 and Comparative Example 1

[0070]

[0071] Compared with Comparative Example 1, special low-temperature glass was added in Example 1, and boric acid and titanium dioxide were added in Example 8. As a result, the residual voltage of Examples 1 and 8 was lower than that of Comparative Example 1, and the charge transfer performance improvement rate was higher than that of Comparative Example 1, indicating that the addition of special low-temperature glass or boric acid and titanium dioxide can reduce the residual voltage of the varistor and improve the charge transfer performance of the varistor.

[0072] Compared with Example 1, special low-temperature glass with different bulk densities was added in Examples 4 to 7. As a result, the residual voltage of Examples 4 to 6 was lower than that of Examples 1 and 7, and the charge transfer performance improvement rate was higher than that of Examples 1 and 7, indicating that when the bulk density of the special low-temperature glass is 0.61-0.81 g / cm 3 ³, and preferably the bulk density is 0.75 g / cm 3 ³, the residual voltage of the obtained varistor is smaller and the charge transfer performance is better.

[0073] Compared with Examples 5 and 8, special low-temperature glass, boric acid, and titanium dioxide were added simultaneously in Examples 9 to 13. As a result, the residual voltage of Examples 9 to 13 was lower than that of Examples 5 and 8, and the charge transfer performance improvement rate was higher than that of Examples 5 and 8, indicating that special low-temperature glass, boric acid, and titanium dioxide play a synergistic role, can reduce the residual voltage of the varistor, and improve the charge transfer performance of the varistor. Among Examples 9 to 13, the residual voltage of Examples 10 to 12 was lower than that of Examples 9 and 13, and the charge transfer performance improvement rate was higher than that of Examples 9 and 13, indicating that when the mass ratio of special low-temperature glass, boric acid, and titanium dioxide is 2-4:1:1, and preferably the ratio is 3:1:1, the residual voltage of the obtained varistor is the smallest and the charge transfer performance is the best.

[0074] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A low-gradient resistor chip for a lightning arrester monitor, characterized in that, It includes the following raw materials in parts by weight: 85 - 90 parts of zinc oxide and 1.2 - 3.6 parts of sintering promoter; the sintering promoter is composed of special low - temperature glass, boric acid, and titanium dioxide with a mass ratio of 2 - 4:1:1; The bulk density of the special low-temperature glass is 0.75 g / cm 3 ; The initial melting temperature of the special low - temperature glass is 450 - 500 °C.

2. The low-gradient resistor chip for an arrester monitor according to claim 1, characterized in that It also includes the following raw materials in parts by weight: 1 - 3 parts of additive, and the additive includes one or more of cobalt sesquioxide, manganese carbonate, antimony trioxide, and chromium sesquioxide.

3. A low-gradient resistor chip for a lightning arrester monitor according to claim 1, characterized in that, It also includes the following raw materials in parts by weight: 1 - 6 parts of flux, and the flux includes one or more of oxalic acid, acetic acid, and citric acid.

4. A low-gradient resistor chip for a lightning arrester monitor according to claim 1, characterized in that, It also includes the following raw materials in parts by weight: 2 - 8 parts of uniformity aid, and the uniformity aid includes one or more of zinc hydroxide, cobalt hydroxide, and nickel hydroxide.

5. The low-gradient resistor chip for a lightning arrester monitor according to claim 1, characterized in that, It also includes the following raw materials in parts by weight: 7 - 10 parts of bismuth - based low - temperature lead - free glass frit, and the bismuth - based low - temperature lead - free glass frit is composed of the following raw materials in parts by weight: 4.5 - 5 parts of bismuth oxide, 0.5 - 1 part of silicon dioxide, 0.5 - 0.8 part of boron trioxide, 0.3 - 0.5 part of aluminum oxide, 0.6 - 0.8 part of calcium oxide, 0.5 - 1 part of lithium oxide, and 0.5 - 0.8 part of potassium oxide.

6. The low-gradient resistor chip for a lightning arrester monitor according to claim 5, characterized in that, The preparation method of the bismuth - based low - temperature lead - free glass frit includes the following steps: mixing the raw materials of the bismuth - based low - temperature lead - free glass frit, melting, cooling, and pulverizing to obtain the bismuth - based low - temperature lead - free glass frit.

7. A preparation method of a low-gradient resistor chip for an arrester monitor according to any one of claims 1 to 6, characterized in that, It includes the following steps: S1. Weigh the zinc oxide sintering promoter in the above parts by weight, mix, granulate, and then press to obtain a green body of the resistor chip; S2. The green body of the resistor chip is dried, calcined, and degummed to obtain a pre - sintered body of the resistor chip; S3. Spray aluminum on the end face of the pre - sintered body of the resistor chip and coat the side face with bismuth - based low - temperature lead - free glass frit, and then sinter to obtain a low - gradient resistor chip.

8. The preparation method of a low-gradient resistor chip for a lightning arrester monitor according to claim 7, characterized in that, The temperature of degumming is 300 - 400 °C, the time of degumming is 1 - 3 h, and the temperature of sintering is 1200 - 1300 °C.

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