DE1952841A1 - Zinc oxide modified with lead as a resistor with variable voltage - Google Patents

Description

Matsushita Electric Industrial Co., Ltd., Kadoma, Osaka, Japan

Zinc oxide modified with lead as a resistor with variable voltage.

Summary:

It is essentially a zinc oxide and off with an addition of lead oxide as a resistor variable; voltage. The, variable voltage resistor off Zinc oxide modified with lead is used in its with respect to the Stress nonlinear properties through a further addition improved by bismuth oxide, calcium oxide and cobalt oxide.

The invention relates to "ceramic masses as a resistor with variable voltage with non-ohmic resistance and in particular on masses as semiconductor resistors that contain zinc oxide, with nlchtohmschem resistance, which can be attributed to the mass itself is.

000837/1860

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Numerous resistors with variable voltage, as for example Silicon conductors, selenium rectifiers and germanium or silicon p-n surface rectifiers, are to a large extent for stabilization the voltage or current of electrical circuits been applied. The electrical characteristics such a variable voltage resistor will be through the equation

expressed in which V is the voltage across the resistor, I the current flowing through the resistor, C a constant corresponding to the voltage at a given current, and the Exponent η is a numerical value greater than 1.

The value for η is calculated according to the following equation:

η =

in the V-. and Vp are the voltages given by the currents I 1 and I _2. The appropriate value for C depends on the type of application for which the resistor is to be used. It is generally advantageous if the value η is as large as possible because this exponent determines the extent to which the resistances deviate from the ohmic values.

With common semiconductor resistors made of germanium or ^; Silicon pn junction rectifiers exist, it is difficult to adjust the C value over a wide range because the ability of these semiconductor resistors to vary the voltage is not based on the composition as such, but on the pn bond range. On the other hand, the silicon carbide semi-conductor resistors have the ability to change the voltage, which is due to the contacts between the individual bodies of the silicon carbide, which are made by a ceramic binder

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are interrelated, and the C-value can change by changing one dimension in one direction in which the stream, through which Semiconductor resistances flow, can be adjusted. The silicon carbide semiconductor resistors however, have a relatively low η value and are produced in such a way that they have a low C value is achieved.

The present invention has for its object to be a Ground for a resistor with variable voltage, and of non-ohmic Kind, with the non-ohmic resistance through the mass sä-bst is conditional, and where the resistor is variable voltage can be adjusted with regard to its C-value for To make available.

Another object of the invention is to provide a mass for a variable voltage resistor characterized by a high η value can be provided.

These and other objects of the invention and their solution are related to the following description can be seen with the accompanying drawing. The drawing shows a partial cross section of a resistor according to the invention with variable voltage again.

Before the proposed according to the invention resistors with variable voltage are described in detail, their Construction will be explained with reference to the drawing, in which the numeral 10 is a variable voltage resistor as Whole referred to, which contains as an effective element a sintered body with a pair of electrodes 2 and 3, which on his opposite surfaces are attached. The sintered body 1 is in a manner described below has been made and has some shape, for example a circular, square, or rectangular plate shape. Lead wires 5 and 6 are through to electrodes 2 and J5 a connecting means 4 such as a solder or the like., conductively connected.

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BATH

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Contains a variable voltage resistor according to the invention a ^ sintered body made of a mass which is essentially borrowed from 90.0 to 99.95 moles of zinc oxide and 0.05 to 10.0 There is lead oxide. Such a resistor with variable voltage has a non-ohmic resistance that acts on the ground itself is due. Therefore, the C-value can be used without any impairment the η value by changing the distance between the two called opposite surfaces are modified. The shorter distance leads to a lower C-value.

The higher η value can be obtained when said sintered one Body according to the invention essentially. 97.0 to 99.9 mol # zinc oxide and 0.1 to 3.0 mol # lead oxide.

According to the invention, the C value can be changed without any change in size and can be decreased without decreasing the η value when said sintered body has a composition which essentially 82.0 to 99.9 mol- # zinc oxide, 0.05 to 10.0 mol- # Lead oxide and 0.05 to 8.0 mol # bismuth oxide.

A combination of a small C-value and a large n-value can be obtained when said sintered body consists essentially of 94.0 to 99.8 mol- # zinc oxide, 0.1 to 3.0 mol- # Lead oxide and 0.1 to 3.0 mol # bismuth oxide.

According to the invention, the resistance to the ambient temperature and the electrical load life can be improved if said sintered body is substantial consists of 82.0 to 99.9 mol- # zinc oxide, 0.05 to 10.0 mol- # lead oxide and 0.05 to 8.0 mol- # calcium oxide. ■. -

Furthermore, the resistance to the ambient temperature and the service life under electrical load in very strong Mass can be improved when the said sintered body is im essentially from 94.0 to 99.8 mol- # zinc oxide, 0.1 to 3.0 mol- # .Lead oxide and 0.1 to 3.0 mol # calcium oxide.

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According to the invention, the η value is increased when said sintered bodies consisting essentially of 82.0 to 99.9 mol- # zinc oxide, 0.05 to 10.0 mole # lead oxide and 0.05 to 8.0 mole # cobalt oxide consists.

The η value is also increased when said sintered body has a composition essentially 9 ^, 0 to 99.8 mole # zinc oxide, 0.1 to 3.0 mole # lead oxide, and 0.1 to 3.0 - $ corresponds to cobalt oxide.

According to the invention, a combination of a high n-value and a low C value can be obtained when said sintered Body has a composition that is essentially 7 ^, 0 to 99.85 mol- ^ zinc oxide, 0.05 to 10.0 mol- # lead oxide, 0.05 to 8.0 mole # cobalt oxide and 0.05 to 8.0 mole # bismuth oxide is equivalent to.

In addition, the G-value can be reduced and the η-value very strong be increased when said sintered body has a composition which is essentially 91 * 0 to 99 * 7 mol- $ Zinc oxide, 0.1 to 3.0 mol- ^ lead oxide, 0.1 to 3.0 mol- # cobalt oxide and 0.1 to 3.0 mole # bismuth oxide.

According to the invention a combination can be achieved by ¹ Iltion hoem η value, a low C-value and high resistance when said sintered body has a composition consisting essentially of zinc oxide from 74.0 to 99.85 mol #, 0, 05 to 10.0 mol- # lead oxide, 0.05 to 8.0 mol- # bismuth oxide and 0.05 to 8.0 Mal-Ji calcium oxide corresponds.

In addition, a combination of extremely high η values can be used for achieved a low C-value and a high level of durability when said sintered body has a composition consisting essentially of 91.0 to 99.7 mole # zinc oxide, 0.1 to 3.0 mole # lead oxide, 0.1 to 3.0 mole # bismuth oxide and 0.1 to 3 ', 0 mol- # corresponds to calcium oxide. -

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The sintered body 1 can be manufactured according to a method known per se in the field of ceramics. the Starting materials for the masses described above are mixed in a wet mill to form homogeneous mixtures. The mixtures are dried and in a form with a pressure

2 2

from 100 kg / cm to 1000 kg / cm to the desired body shape pressed together. The compressed bodies become in air sintered at a given temperature for 1 to 3 hours and then in the furnace to room temperature (about 15 ° to about 30 ° C) cooled down. .

The suitable inter tempera door is from the point of view of the electrical resistivity, non-linearity and Resistance is determined and ranges from 1000 ° to 1450 ° C.

The compressed bodies are when the electrical specific Resistance is to be reduced, preferably in a non-oxidizing atmosphere such as nitrogen and argon, sintered. ..-.- "■

The mixtures can be used for easier handling during the following. Pressing process first calcined at 700 ° to 1000 ° C and then powdered. The mixture to be compressed can be mixed with a suitable binder such as water, polyvinyl alcohol, etc. ■ - - , "

It is beneficial if the sintered body to the opposite Surfaces with abrasive powder, such as silicon carbide with a particle size of 300 to 1500 mesh, is ground or polished.

The sintered bodies are on their opposite surfaces with electrodes by any applicable and suitable method, such as for example by electroplating, vacuum evaporation, metallization, sputtering or after Silver painting method provided.

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The capabilities ZiJm = changing the voltage are practically not influenced by the type of electrodes used, but by the thicknesses of the sintered bodies. In particular, the C value changes according to the thickness of the sintered body, while the η value is almost independent of the thickness. This clearly shows that the ability to change the. Voltage is due to the mass itself and not to the electrode . - ■■ .-. ■

Lead wires can be made in a manner known per se using a conventional solder having a low melting point be attached. It is convenient to use a conductive adhesive that is silver powder and resin in an organic solvent contains, for connecting the lead wires to the electrodes to use.

The variable voltage resistors according to the invention have a high resistance to the temperature and to an endurance test at 70 ° C for an operating time running for 500 hours. The η value and the C value change according to the effects of warming and the endurance test not noticeable. It is advantageous to achieve a high resistance to moisture if the obtained Variable voltage resistors in a moisture-proof resin, such as epoxy resin and phenolic resin, per se known way 'embedded.

Currently Preferred Embodiments of the Invention «* become explained below.

example 1

A mixture of zinc oxide and lead oxide with one of the table 1 corresponding composition is in a wet mill for 3 hours long mixed. The mixture is dried and then 1 hour

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calcined at 700 ° C for a long time. The calcined mixture is with Using a motorized ceramic mortar within 50 Minutes and then pulverized in a mold with a pressure of 500 kg / cm into a body frame with a diameter of 17.5 mm and a thickness of 2.5 mm.

The compressed body is in air at 1350 ° C for 1 hour sintered for a long time and then cooled in the furnace to room temperature (to about 15 ° to about 30 ° C). The sintered disc will turn on the opposite surfaces with the help of silicon carbide ground with a particle size of 600 mesh. The resulting sintered disk has a size of 14 mm in diameter and 1.5mm thickness. The commercially available electrodes made of silver paint are sintered on the opposite surfaces of the Disc attached with the help of a paint. Then the lead wires are connected to the silver electrodes by soldering. The electrical properties of the resistors obtained are shown in Table 1. It can be seen that the sintered bodies made of zinc oxide with a content of lead oxide in an amount of 0.05 to 10.0 mole # for resistance variable voltage is suitable. In particular, an addition of lead oxide in an amount of 0.1 to 3.0 mol # leads to the tension to an even more pronounced non-linear behavior.

C. Tabel 1 PbO C. η PbO (at ImA) (Mol- #) (at ImA) 5.0 (Mol- #) 1010 η 2 870 4.8 0.05 900 3.2 3 920 . : 3.5 0.1 840 4.7 5 1030 3.2 0.2 800 5.1 8th 1100 3.0 0.5 835 5.5 10 1200 1 5.3

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Example 2

Anas 99.5 mol # zinc oxide and 0.5 mol # lead oxide existing starting materials are mixed, dried, calcined μηα pulverized in the manner described in Example 1. Bas powdered mixture in a mold to a shape won 17.5 nim diameter and 5 mm thickness at a pressure of

2 5ΌΟ kg / cm compressed.

The compressed body is sintered in air at 1350 ° C. for 1 hour and then cooled to room temperature in the oven. The sintered disk is ground on the opposite surfaces to a thickness which is given in Table 2 using silicon carbide with a particle size of 600 mesh. The ground disk is stranded with the electrodes and the lead wires on the opposite surfaces in the manner indicated in Example 1. The electrical values of the resistances obtained are given in Table 2; the C value changes approximately proportionally to the thickness of the sintered disk, while the η value is practically independent of the thickness. It is easy to see that the lains i t borrowed from the stress is attributable to the non-linear behavior of the resistances to the sintered body itself.

(mm) Table 2 η thickness (4.0) C (at ImA) 5.5 at first 2100 5.4 3.5 I85O 5.6 3.0 1600 5.5. 2.5 1330 5.5 2.0 IO5O 5.5 1.5 8OO 5.4 1.0 530

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Example 3 '

Made of zinc oxide with a content of lead oxide and bismuth oxide accordingly a proportion specified in Table 3 are resistors with variable voltage according to the example in Example_1 described procedure. The properties achieved The resistances are given in Table 3. It can easily be seen that the combination of lead oxide and bismuth oxide as an additive leads to low C values without the η value changing to a correspondingly large extent.

Table 3 C. η PbO BipO., (at ImA) 3.3 (Mol- *) ' 700 3.1 0.05 0.05 '■ "*' 205 3.1 0.05 0.5 .690 5.4 0.05 8th 530 5.4 0.5 0.05 540 3.2 0.5 8th 800 3.1 10 0.05 24o 3.0 10 0.5 810 4.8 10 8th 450 4.7 ο, ι 0.1 445 4.8 0.1 0.5 460 5.4 0.1 3 530 5.5 0.5 0.1 535 4.9 0.5 3 600 4.9 3 0.1 180 4.6 3 o, 5 460 5.5 3 3 160 0.5 0.5

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Resistors with variable voltage are produced from zinc oxide with a content of lead oxide and calcium oxide in a proportion given in Table 4 according to the process route given in Example 1. The resistances obtained are tested according to the methods used for electronic parts. The "Belastung'sdauerprobe is carried out at 70 ° C ambient temperature and at 0.5 Watt power within a period of 500 hours. The Erwärmungsw4.ederhpltangstest is maintained for 30 minutes by five times repeating a Folgef ^ wherein the said resistors at 85 ⁰ C ambient temperature , then rapidly cooled to -20 ° C. and held at this temperature for 30 minutes. Table 4 shows a difference for the C value and the η value of the resistances before and after the endurance test. It is easy ^to see that the combination of lead oxide and calcium oxide as an additive influences the electrical durability and the resistance to the environment.

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PbO

CaO

- 12 Table 4
Load duration test t

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Periodic heating test

0.05 0.05 0.05 0.5 0.05 • 8th 0.5 0.05 0.5 8th 10 0.05 10 0.5 10 8th 0.1 0.1 0.1 0.5 0.1 3 0.5 0.1 0.5 3 3 0.1 3 0.5 3 3 0.5 0.5 Example 5

-9.0 -8.8 -6.9 -6.5 -7.4 -7.5 -5.8 -5.9 -6.2 -6.0 -8.2 -8.1 -7.1 -7.4 -9.4 -9.0 -4.8 -4.8 -3.0 -3.4 -4.7 -5.0 -5.3 -5.0 -4.9 -4.8 -3.8 -3.7 -2.6 -2.5 -3.7 -3.8 -1.3 -2.0

-7.9 -8.3 -6.0 -6.2 -7.1 -7.1 -6.8 -6.9 -6.7 -6.7 -7.2 -7.5 -5.9 -6.3 -8.0 -8.1 -4.0 -4.2 -2.9 -2.8 -3.2 -3.5 -3.0 -3.5 -3.4 -3.2 -3.4 -3.1 -2.0 -1.9 -2.9 -2.2 -1.5 -1.5

Made of zinc oxide, which contains the additives specified in Table 5, variable voltage resistors are produced according to the procedures described in Example 1. The n-values the resistances obtained are given in Table 5. It is easy to see that the combination of lead oxide and cobalt oxide as an additive in a pronounced way with regard to an extraordinarily strong non-linear behavior the tension leads.

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Example 6 Table 5 CoO C. η PbO (MoI- *) (at ImA) ..-; ■. (MoI- ^) 0.05 103o 4.8 0.05 0.5 990- 9.5 0.05 8th 1000 4.9 0.05 0.05 800 8.0 0.5 8th 790 7.5 0.5 0.05 .1150 4.5 10 0.5 ii4o 9.0 10 8th ii6o 4.6 10 0.1 910 9.5 0.1 0.5 900 14th 0.1 3 890 9.4 0.1 _: ο, ι 800 8.0 0.5 3 780- 7.8 0.5 0.1 900 7.0 3 0.5 910 14th 3 3 900 9.5 3 0.5 790 16 0.5

Made of zinc oxide, which contains the additives specified in Table 6, are according to the procedure described in Example 1 gang resistors made with variable voltage. The electric Properties of the resistors obtained are shown in the Table 6 given. It's easy to see the combination of lead oxide, cobalt oxide and bismuth oxide as additives in a pronounced manner to an excellent η value and at the same time leads to a lower C-value.

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CoO Table 6 (at ImA) η PbO (Mol- *) Bi ₂ O ₃ 700 (MoI ^) , '. ^Ö ' ^Q 5 (Mol-i) - 680 4.7 0.05 0.05 0.05 720 4.5 0.05 8th 8th 750 4.9 0.05 8th 0.05 700 5.0 0.05 0.05 ,8th 720 4.4 10 0.05 0.05 790 4.6 10 8th 8th 8oo 4.6 10 8th " 0.05 450 4.5 10 0.1 8th 440 9.5 0.1 0.1 0.1 440 9.3 0.1 3 3 420 9.4 0.1 3 0.1 450 8.8 0.1 0.1 3 460 7.0 3 0.1 0.1 455 7.0 .3 3 3 450 9.5 3 3 0.1 160 9.5 3 0.5 3 16 0.5 0.5 Example 7

From zinc oxide, which contains the additives indicated in Table 7, resistors with variable voltage are produced according to the method described in Example 1. The resistors obtained are tested under the same conditions as in Example 4. Table J shows the initial C value and the difference in the C value and the η value, which result from the values before and after the endurance test. It can easily be seen that when the combination of lead oxide, bismuth oxide and calcium oxide is used as an additive, the initial C value of the resistance is reduced and that at the same time

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the resistance to electrical and environmental endurance tests is excellent.

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BiO CaO C. Table 7 '<) An (Ji) PbO (MoI-Ji) (MoI-Ji) (at ImA) Load duration test -9.2 \ MoI-Ji) 0.05 0.05 65O Λ c {% -8.6 0.05 0.05 8th 190 -8.4 -7.2 0.05 8th 0.05 670- -6.0 -6.9 0.05 8th 8th 500 -7.2 -8.3 0.05 0.05 0.05 515 -6.9 -7.7 10 0.05 8th 750 -5.9 -8.0 10 8th 0.05 225 -7.3 -9.3 10 8th 8th 8OO -6.8 -5.0 10 ο, ι 0.1 45O -7.9 -4.7 0.1 0.1 3 420 -4.0 -4.8 0.1 3 ο, ι 400 -4.2 -3.8 0.1 3 3 490 -3.9 -4.2 0.1 ο, ι 0.1 510 -4.9 -5.0, 3 ο, ι 3 56O -5.2 - -4.8 3 3 · ο, ι 'I65 -3.4 -4.9 3 3 3 420 -4.1 -1.2 3 0.5 0.5 135 -5.0 0.5 -0.8

Periodic heating test

ο ο co

-7.9 ■ 7.2 • 7.8 -6.9 ■ 7.3 ■ 6.9 ■ 7.4 -8.5 -5.0 -4.8 ■ 5.0 -4.1 ■ 3 , 9 -5.0 -4.7 -4.5 -1.3

-8.5 -6.4

-7.3 -6.8

-5.9 -7.8

-7.7 -8.3 -4.2 -4.4 -4.3 -3.9 -4.1

-4.5 -3.0 -3.4 -0.9

Claims (6)

Pat tan's sayings: Ceramic mass as a resistor with variable voltage, characterized in that the mass consists essentially of zinc oxide and 0.05 to 10.0 mol- # lead oxide _ .. 2. Ceramic mass as a resistor with variable voltage according to claim 1, characterized in that the mass consists essentially of zinc oxide and 0.1 to 3.0 mol # lead oxide. , - ■ · ■■■ 3. Ceramic mass as a resistor with variable voltage according to claim 1, characterized in that the mass also contains 0.05 to 8.0 mol $ of an oxide ^, the from the one consisting of bismuth oxide, calcium oxide and cobalt oxide Group has been elected. 4. Ceramic mass as a resistor with variable voltage according to claim 2, characterized in that the mass also contains 0.1 to 3.0 mol $ of an oxide selected from the group consisting of bismuth oxide, calcium oxide and cobalt oxide. ORIGINAL INSPECTED 009837/1860 5. Ceramic mass as a resistor with variable voltage according to claim 1, characterized in that the mass also 0.05 to 8.0 mol $ bismuth oxide and 0.05 to 8.0 Mol $ of an oxide that is derived from that of calcium oxide and cobalt oxide existing group has been selected. 6. Ceramic mass as a resistor with variable voltage according to claim 2, characterized in that the mass also 0.1 to 3.0 moles of bismuth oxide and 0.1 to 3.0 Mol $ of an oxide that is derived from that of calcium oxide and cobalt oxide existing group has been selected. Dr. Ve. / Br. 009837/1860