UA129719U - VARISTORY MATERIAL BASED ON Tungsten Oxide - Google Patents

Abstract

The material for varistors based on tungsten oxide WO3 includes the addition of sodium oxides Na2O and manganese MnO2. Al2O3 alumina is added to the material.

Description

A useful model belongs to electronic engineering and can be used in the production of low-voltage ceramic varistors, which are used to protect electrical circuits from overvoltages.

A well-known ceramic material with nonlinear electrical properties based on tin oxide with additions of cobalt oxides and antimony (|, is widely used for the production of varistors. However, this material has a high classification voltage (160 V/mm), which does not allow it to be used in low-voltage devices, and requires a very high firing temperature (1600 2).

A known material for low-voltage varistors based on titanium oxide |21| with additions of strontium and niobium oxides. This material provides a low-voltage range of rated voltage. The disadvantage of such material is a small (3-4) coefficient of nonlinearity of the I-V.

The closest to a useful model is the material for low-voltage varistors based on tungsten oxide UMOz |IZI, with additions of sodium MagO and manganese MpoO:» (prototype). This material has a coefficient of nonlinearity of 4.5-5. The disadvantage of the known material is a small classification voltage of 6-10 V/mm.

The task of a useful model is to increase the classification voltage.

The problem is solved by the fact that in the known material for low-voltage varistors based on tungsten oxide, which includes additives of sodium oxides MagO and manganese

MpO», the new thing is that aluminum oxide AOz is added to the composition of the material with the following ratio of components, mol. 9: aluminum oxide Az 0.3-3.0 sodium oxide MagO 0.3-2.0 manganese oxide MpO»2 0.3-3.0 tungsten oxide UMOz the rest.

This composition provides an increase in the classification voltage of varistors.

To evaluate the varistor properties of the material, samples of the known material were prepared on the basis of M/Oz, which includes additives of sodium oxides of 0.3-2.0 mol. 95 and manganese 0.3-3.0 mol. 95 with different contents of aluminum oxide. IVA was measured at direct current and was non-linear. As parameters characterizing the nonlinear I/V, the coefficient of nonlinearity of the I/V was chosen, which was calculated according to the formula: c-Ta) -19)2

I9Ei -19E2 - -4 in the area of currents I -10 7 and 92-10 A/cm, and the classification voltage was determined at a current of 1 mA/cm - For electrical measurements, copper electrodes were applied to the surface of the disks

By the method of thermal spraying in a vacuum.

The material for the varistors was obtained in the following way.

Corresponding quantities of powders of tungsten oxide (brand "khch"), manganese oxide (brand "h"), sodium carbon dioxide (Mag2bOz brand "osch") and aluminum oxide (brand "h") were mixed with the addition of ethyl alcohol. Then the charge was dried at a temperature of 120 °C and the blanks were pressed in the form of discs with a diameter of 12 mm and a thickness of 1.5 mm under a pressure of 200 kg/cm?. The blanks were fired in air in a muffle furnace at 1100 "C for two hours and cooled together with the furnace.

The test results are presented in the table.

Table

Electrical parameters of the UMOz material - (0.3-2.0) mol. 95

Mago - (0.3-3.0) mol. 965 МпО:» for low-voltage varistors with different content of AIYUz peren v v v p

MOL. What | MOL. 9 nonlinearities V/mm 71. 0 105105 | 5 sh shyuBKk5 | (82 4 yuYUK | prototype 41 03 10513930 | sh 5 | 2 | - 5 03 | 05 | 03 | sh 50 | 20 | - 61 03 | 03 | 05 | sh shKk50 | 19 | - 7 03 | 20 | 05 | 5 | 2 | -

Table

Electrical parameters of the UMOz material - (0.3-2.0) mol. 95

Mago - (0.3-3.0) mol. 965 МпО:» for low-voltage varistors with different contents of AIЯz peren v ev lin

MOL. because | MOL. In nonlinearity V/mm 8.| 05 | 05 | 05 | 57 | 27 | - 9.1, 10 | 05 | 05 | sh 52 | 25 '| - 10. 15 | 05 | 05 | 5 sh KZ45 | 2 | - 20 | 05 | 05 | 48 | 2 | - 12.| 25 | 05 | 05 | sh 52 | 24 | - 13.d.,| 30 | 05 | 05 | 42 | 18 | - 14| 30 | 05 | 03 | 43 | 19 | - 151 30 | 05 | 30 | 44 | 20 | - 4:30 p.m 03 | 05 | 43 | - | -

As can be seen from the table, within the composition of the useful model, the obtained ceramic material has non-linear electrical properties with a higher classification voltage. The greatest positive effect is achieved when the content of aluminum oxide is in the range of 0.3-3.0 mol. 95. When choosing a material composition outside the specified limits, it has worse electrical parameters.

The optimal composition necessary to achieve the goal of a useful model should be considered a material based on tungsten oxide containing 0.5 mol. 95 Mag2O-0.5 mol. 96 MPO" and 0.5 mol. 95 Az. In this composition, the most optimal combination of electrical parameters of the material is achieved.

The use of the declared useful model will allow more effective protection of low-voltage electric circuits from overvoltages due to a higher classification voltage and to reduce the energy consumption of the production process of low-voltage varistors due to a low firing temperature.

Sources of information: 1. Japan patent Mo 5247158, Magegia! yitog pop Iipeag geziviog. NOTSO 7/10, 1978. 2. A.b. USSR Mo 1468282, Material for low-voltage varistors. NO 1C 7/10, 1986... 3. Patent of Ukraine for utility model Mo 124086 Material for low-voltage varistors.

НО1С 7/10, 2018

Claims (1)

USEFUL MODEL FORMULA Material for varistors based on tungsten oxide M/Oz, which contains additives of sodium oxides MagO and manganese MpO", which differs in that aluminum oxide A/25Oz is added to the composition of the material, with the following ratio of components, by weight. 9o: aluminum oxide A/I2Oz 0.3-3.0 sodium Maho oxide 0.3-2.0 manganese oxide MpO» 0.3-3.0 tungsten oxide U/Oz the rest.