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Zinc oxide pressure-sensitive ceramic material doped with composite rare-earth oxide

A rare earth oxide and compound rare earth technology, applied in varistor and other directions, can solve the problem of affecting the comprehensive electrical properties of ceramic dielectric potential gradient, and achieve the effects of excellent comprehensive performance, high density and simple process

Inactive Publication Date: 2008-10-08
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above methods generally use rare earth oxides to increase the potential gradient of zinc oxide varistors, but there is room for further improvement in the comprehensive electrical properties of varistors
At the same time, the current research focus on the doping of rare earth oxides is mainly focused on the type of additives on the traditional ZnO-Bi 2 o 3 Influenced by the microstructure of varistor ceramics, if the type of additive is not selected properly or the amount of addition is inappropriate, it will affect the improvement of the potential gradient of the ceramic dielectric and the improvement of the comprehensive electrical properties.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] (1) Weigh the molar ratio of ZnO96.72%, MnO respectively 2 0.5%, Co 2 o 3 0.5%, Bi 2 o 3 0.5%, Cr 2 o 3 0.5%, Sb 2 o 3 1.0%, Sc 2 o 3 0.2%, Y 2 o 3 0.08%.

[0022] (2) Adopt zirconia balls, polyethylene jars, absolute ethanol and distilled water as ball milling media, wet mill in a frequency conversion planetary ball mill for 5 hours, rotating speed 500rpm, ball: powder: the mass ratio of absolute ethanol is 20: 1: 4 .

[0023] (3) The ball-milled slurry is baked at 70°C for 24 hours to become a dry powder.

[0024] (4) Calcined at 700°C for 2h.

[0025] (5) The calcined powder is dry-milled for 1 hour in a frequency conversion planetary ball mill with a speed of 500 rpm using zirconia balls and a polyethylene tank.

[0026] (6) After dry grinding, the powder is pressed into shape after adding 8% of PVA with a mass fraction of 2%.

[0027] (7) The pressed green body is heated up to 500°C at a rate of 5°C / min in a resistance furnace, kept in an air atmosp...

Embodiment 2

[0031] In this example, the molar ratio is ZnO96.3%, MnO 2 0.5%, Co 2 o 3 0.8%, Bi 2 o 3 0.7%, Cr 2 o 3 0.5%, Sb 2 o 3 1.0%, Sc 2 o 3 0.1%, Y 2 o 3 0.1%. Mix uniformly to form a zinc oxide varistor material. The above materials are manufactured into zinc oxide varistor ceramics by the same process steps as in Example 1, the difference from Example 1 is that the sintering temperature of the sintering process is 1000°C.

[0032] The zinc oxide varistor produced in this embodiment has been tested through performance, and the potential gradient reaches 1320V / mm, the leakage current is 10.5μA, and the nonlinear coefficient is 33.

Embodiment 3

[0034] In this example, the molar ratio is ZnO96.21%, MnO 2 0.5%, Co 2 o 3 0.8%, Bi 2 o 3 0.7%, Cr 2 o 3 0.5%, Sb 2 o 3 1.0%, Sc 2 o 3 0.08%, Al 2 o 3 0.01%, Y 2 o 3 0.2%. Mix evenly to form zinc oxide varistor materials. The above materials are manufactured into zinc oxide varistor ceramics by the same process steps as in Example 1, the difference from Example 1 is that the sintering temperature in the sintering process is 1100°C.

[0035] The zinc oxide varistor produced in this embodiment has been tested through performance, and the potential gradient reaches 1430V / mm, the leakage current is 2.3μA, and the nonlinear coefficient is 46.

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Abstract

The invention relates to a zinc oxide varistor ceramic material doped with a composite rare earth oxide and a method for the production thereof, which belongs to the functional ceramic material manufacturing technique field. The ceramic material is characterized in that the zinc oxide varistor resistance material comprises the following compositions of 95 percent to 98 percent of ZnO as a main material, respectively 0.1 percent to 1.0 percent of MnO2, Co2O3, Bi2O3, Cr2O3 and Sb2O3, and 0.01 percent to 0.4 percent of composite rare earth oxide by molar percentage, wherein the composite rare earth oxide is one of Sc2O3, rare earth oxide Y2O3, La2O3, Ce2O3, Er2O3, Dy2O3 and Nd2O3 non-doped or doped with Al2O3. The invention increases the electric potential gradient of the zinc oxide varistor ceramic to between 1300 and 1600V / mm through adjusting the reasonable proportion of the composite rare earth oxide, and the non-linear coefficient is between 30 and 50 and the leakage current is between 2 and 20 mu A. The varistor ceramic of the invention can be used for making high grade lightning protector products with supervoltage electric systems.

Description

technical field [0001] The invention relates to a zinc oxide pressure-sensitive ceramic material doped with composite rare earth oxide, and belongs to the technical field of functional ceramic material manufacturing. Background technique [0002] ZnO varistor ceramics is based on ZnO powder, adding trace amounts of other metal oxide additives (such as Bi 2 o 3 , Sb 2 o 3 ,Co 2 o 3 , MnO 2 , Cr 2 o 3 etc.), a polycrystalline semiconductor ceramic element that is sintered at high temperature after mixing and molding. [0003] Since the development of ZnO varistors by Panasonic in Japan in 1968, ZnO varistors have excellent performances such as low cost, convenient manufacturing, large nonlinear coefficient, fast response time, low residual voltage, small voltage temperature coefficient, and small leakage current. It is widely used in high-voltage transmission lines, urban subway DC power supply lines and railway grid systems. With the development of ultra-high voltag...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C04B35/453H01C7/10
Inventor 施利毅徐东钟庆东巫欣欣吴振红
Owner SHANGHAI UNIV
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