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Low-temperature sintered zinc oxide voltage-sensitive ceramic material and preparation method thereof

A technology of varistor ceramics and low-temperature sintering, applied in varistors, varistor cores, etc., can solve the problems of unfavorable environment, lower sintering temperature, poor flow capacity, etc., and achieve good overall performance and low sintering temperature , The effect of simple process

Active Publication Date: 2013-10-16
SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

To sum up: the wet chemical method is complicated in process and high in cost, and is not suitable for large-scale industrial production; the high-energy ball milling method is easy to incorporate impurities, and the particles are easy to deform; Its preparation process is simple, the cooling efficiency is high, and it has good compatibility with ZnO varistors. It is currently the most feasible low-temperature sintering method, but the co-solvent added currently generally contains PbO, which is not good for the environment. For example, the US patent US5369390 " Multilayer ZnO varistor", mainly by adding PbO, B 2 o 3 , ZnO and SiO 2 Composition of glass frit, to lower the sintering temperature
while the simple B 2 o 3 Glass frit will affect the electrical properties of ZnO
The reduction of sintering temperature will lead to insufficient grain development, and the grains are too small, so that the ceramic gradient is too high and the flow capacity is poor

Method used

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  • Low-temperature sintered zinc oxide voltage-sensitive ceramic material and preparation method thereof
  • Low-temperature sintered zinc oxide voltage-sensitive ceramic material and preparation method thereof
  • Low-temperature sintered zinc oxide voltage-sensitive ceramic material and preparation method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0019] The formula of this embodiment is as follows:

[0020] ZnO (95.449mol%), Bi 2 o 3 (1.0mol%), Sb 2 o 3 (0.5mol%), B 2 o 3 (0.5mol%), NiO (0.5mol%), Co 2 o 3 (0.7mol%), MnO 2 (0.3mol%), Cr 2 o 3 (1.0mol%), MoO 3 (0.001mol%), V 2 o 5 (0.05 mol%).

[0021] Put the above materials together into a nylon tank, use zirconia balls or stainless steel balls, and use water as the medium for wet grinding in a planetary ball mill at a speed of 500rpm, with a material-to-ball ratio of 10:1, and ball mill for 8 hours; bake the slurry at 120°C After drying, calcinate at 300°C for 2 hours to obtain composite powder; then add 10% PVA binder, artificially granulate, and then press out a green body with a diameter of 12mm; figure 1 The one-step sintering method shown is for sintering, that is, the temperature is first raised to 800°C at a heating rate of 3°C / min, and then raised to 900°C at a heating rate of 2°C / min, kept for 120 minutes, and then cooled with the furnace to ob...

Embodiment 2

[0024] The formula of this embodiment is as follows:

[0025] ZnO (94.95mol%), Bi 2 o 3 (1.0mol%), Sb 2 o 3 (0.5mol%), B 2 o 3 (0.5mol%), NiO (0.5mol%), Co 2 o 3 (0.7mol%), MnO 2 (0.3mol%), Cr 2 o 3 (1.0mol%), MoO 3 (0.5mol%), V 2 o 5 (0.05 mol%).

[0026] Operated as described in Example 1, a ZnO varistor ceramic material with a density of 96.0% was obtained.

[0027] Use screen printing to coat silver, and burn silver at 500°C for 1 hour to obtain a varistor with a varistor voltage of 760V / mm, a nonlinear coefficient of 28, and a leakage current of 2.5μA.

Embodiment 3

[0029] The formula of this embodiment is as follows:

[0030] ZnO (94.95mol%), Bi 2 o 3 (1.0mol%), Sb 2 o 3 (0.5mol%), B 2 o 3 (0.5mol%), NiO (0.5mol%), Co 2 o 3 (0.7mol%), MnO 2 (0.3mol%), Cr 2 o 3 (1.0mol%), sintering aid BM (0.5mol%), V 2 o 5 (0.05 mol%).

[0031] MoO 3 with Bi 2 o 3 Mixed at a molar ratio of 2.0:1, then ball milled for 4 to 8 hours to make the mixture uniform, and then calcined at 650°C for 4 hours, the obtained MoO 3 with Bi 2 o 3 The mixture is called sintering aid BM.

[0032] The obtained sintering aid BM was uniformly mixed with zinc oxide and modifying additives according to the ratio, and operated as described in Example 1 to obtain a ZnO varistor ceramic material with a density of 96.5%.

[0033] Use screen printing to coat silver, and burn silver at 500°C for 1 hour to obtain a varistor with a varistor voltage of 740V / mm, a nonlinear coefficient of 35, and a leakage current of 0.8μA.

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Abstract

The invention discloses a low-temperature sintered zinc oxide voltage-sensitive ceramic material and a preparation method thereof. The low-temperature sintered zinc oxide voltage-sensitive ceramic material consists of zinc oxide with the content of 86.0-98.0 mol%, a sintering accessory ingredient with the content of0.001-3.0 mol% and a modified additive with the balance content, wherein the sintering accessory ingredient is MoO3 or a mixture of MoO3 and Bi2O3; and the modified additive consists of Bi2O3, Sb2O3, B2O3, NiO, Co2O3, MnO2, Cr2O3 and V2O5. The zinc oxide voltage-sensitive ceramic material has the pressure sensitive voltage of 730-800 V / mm, a nonlinear coefficient alpha of more than 20 and leakage current IL of less than 10 muA and is low in sintering temperature and high in comprehensive performance; furthermore, the preparation method has the advantages of simple process, low energy consumption, environment-friendliness and the like; and the low-temperature sintered zinc oxide voltage-sensitive ceramic material has practicability and an application prospect.

Description

technical field [0001] The invention relates to a low-temperature sintered zinc oxide (ZnO) pressure-sensitive ceramic material and a preparation method thereof, belonging to the technical field of pressure-sensitive ceramic materials. Background technique [0002] ZnO-based ceramics have become the most widely used varistor materials due to their advantages of high nonlinear coefficient, high surge absorption capacity, fast response speed, etc., as well as low cost and simple process. With the rapid development of electronic information technology, electronic components are developing in the direction of low voltage, miniaturization, array and integration. Therefore, the multilayer chip ZnO varistor with miniaturization and high reliability has a good market prospect. In the increasingly fierce price war situation, the expensive price of chip varistors has become the main bottleneck affecting its market share and promotion. The sintering temperature of the ZnO varistor ma...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C04B35/453C04B35/622H01C7/112
Inventor 李国荣肖祥凯程丽红郑嘹赢阮学政曾江涛
Owner SHANGHAI INST OF CERAMIC CHEM & TECH CHINESE ACAD OF SCI