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A rare earth oxide modified tin dioxide varistor material and preparation method thereof

A rare earth oxide, tin dioxide technology, applied in varistor and other directions, can solve the problem of no residual voltage ratio report, can not meet the practical application and other problems, achieve the effect of excellent electrical performance, high potential gradient, low residual voltage ratio

Active Publication Date: 2015-12-30
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Recently, although there are also high potential gradient SnO 2 Research on the nonlinear electrical properties of varistors, but there is no report on its residual voltage ratio
The inventors previously studied the rare earth oxide La 2 o 3 ,Pr 2 o 3 , Dy 2 o 3 ,Er 2 o 3 Modified high potential gradient SnO 2 Varistor research finds that rare earth oxides can improve SnO 2 The potential gradient of the varistor (up to 1000V / mm), but the residual voltage ratio is far greater than 3, which cannot meet the needs of practical applications

Method used

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  • A rare earth oxide modified tin dioxide varistor material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] Weigh 98.2mol% of SnO by molar ratio 2 , 1.0mol% CoO, 0.05mol% Ta 2 o 5 , 0.05mol% Cr 2 o 3 , 0.35mol% CeO 2 and 0.35mol% Eu 2 o 3 ;

[0022] Mix the weighed mixed powder with zirconia balls and deionized water in a mass ratio of 2:6:3 in a polyurethane ball mill tank, mix and grind on a ball mill, and mill for 12 hours;

[0023] Put the finely mixed slurry into a drying oven, and dry it at 150°C for 5 hours;

[0024] Add a mass fraction of 5% PVA binder to the dried powder, the ratio of powder to polyvinyl alcohol is 20:1, the unit is g / mL, pass through a 100 mesh sieve, and granulate;

[0025] The granulated powder is dry-pressed in a mold, sintered, and the sintering temperature is 1300°C, and the temperature is kept for 3 hours;

[0026] The tin dioxide varistor sintered body is coated with silver to make electrodes, and lead wires are welded on the silver electrodes, and then encapsulated and solidified to make a disc with a diameter of 12mm.

[0027] Aft...

Embodiment 2

[0029] Weigh 97.93mol% of SnO by molar ratio 2 , 1.0mol% CoO, 0.05mol% Ta 2 o 5 , 0.02mol% Cr 2 o 3 , 0.5mol% CeO 2 and 0.5mol% Eu 2 o 3 ;

[0030] Mix the weighed mixed powder with zirconia balls and deionized water in a mass ratio of 2:6:3 in a polyurethane ball mill tank, mix and grind on a ball mill, and mill for 24 hours;

[0031] Put the finely mixed slurry into a drying oven, and dry it at 120°C for 8 hours;

[0032] Add a mass fraction of 5% PVA adhesive to the dried powder, the ratio of powder to polyvinyl alcohol is 20:1, the unit is g / mL, pass through a 60-mesh sieve, and granulate;

[0033]The granulated powder is dry-pressed in a mold, sintered, and the sintering temperature is 1300°C, and the temperature is kept for 3 hours;

[0034] The tin dioxide varistor sintered body is coated with silver to make electrodes, and lead wires are welded on the silver electrodes, and then encapsulated and solidified to make a disc with a diameter of 12mm.

[0035] Afte...

Embodiment 3

[0037] Weigh 97.4mol% of SnO by molar ratio 2 , 1.0mol% CoO, 0.06mol% Ta 2 o 5 , 0.04mol% Cr 2 o 3 , 0.75mol% CeO 2 and 0.75mol% Eu 2 o 3 ;

[0038] Mix the weighed mixed powder with zirconia balls and deionized water in a mass ratio of 2:6:3 in a polyurethane ball mill tank, mix and grind on a ball mill, and mill for 8 hours;

[0039] Put the finely mixed slurry into a drying oven, and dry it at 100°C for 10 hours;

[0040] Add a mass fraction of 5% PVA adhesive to the dried powder, the ratio of the powder to the polyvinyl alcohol solution is 20:1, the unit is g / mL, pass through a 140 mesh sieve, and granulate;

[0041] The granulated powder is dry-pressed in a mold, sintered, and the sintering temperature is 1300°C, and the temperature is kept for 3 hours;

[0042] The tin dioxide varistor sintered body is coated with silver to make electrodes, and lead wires are welded on the silver electrodes, and then encapsulated and solidified to make a disc with a diameter of ...

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PUM

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Abstract

The invention discloses a rare earth oxide-modified stannic oxide varistor material. The raw material for the stannic oxide varistor material is composed of the following mixed powder by mole: 95.0 to 99.0% of stannic oxide, 0.5 to 2.0% of cobalt oxide, 0.05 to 1.0% of tantalum pentoxide, 0 to 1.0% of chrome oxide, 0.05 to 1.0% of rare earth oxide--cerium oxide and 0.05 to 1.0% of rare earth oxide--europium oxide. The stannic oxide varistor material is prepared through ball milling, granulation, molding, sintering (wherein sintering temperature is 1250 to 1500 DEG C and is maintained for 3 h), preparation of electrodes, welding of leads and encapsulation and curing. According to performance test results of the stannic oxide varistor material prepared by using the method, the stannic oxide varistor material has electrical properties like a comparable residual voltage ratio, a comparable nonlinear coefficient, higher electric potential gradient and the like compared with a commercial ZnO-based varistor and also has a simple microstructure and better stability.

Description

technical field [0001] The invention relates to a rare earth oxide modified tin dioxide (SnO 2 ) varistor material and its preparation method. Background technique [0002] Varistor materials are materials used to make piezoresistors, which are electronic devices that are very sensitive to voltage. In a certain temperature and a specific voltage range, the current of the varistor increases sharply with the increase of the voltage, and its resistance value decreases sharply with the increase of the voltage, which has nonlinear volt-ampere characteristics. Varistors can effectively protect electronic devices, electronic circuits, electronic equipment, and electrical equipment from abnormal voltage shocks by absorbing pulse voltage, surge voltage, induced lightning voltage, and operating overvoltage. The working principle of the varistor is: when the voltage is normal, the varistor is in an insulating state (its resistance is tens to hundreds of megohms), when the voltage ris...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01C7/10C04B35/457C04B35/622
Inventor 王春明陈洪存
Owner SHANDONG UNIV
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