DE1961680C3 - Voltage-dependent resistor based on zinc oxide - Google Patents

Description

in which V is the voltage / the current flowing through the resistor, C is a constant which corresponds 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 =

which are V ₁ and V ₂ by the currents /, and I ₂ given "voltages, usually from /, and I ₂ 10 and 10OmA. 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 degree of non-linearity, ie the deviation from the ohmic values.

Silicon carbide semiconductor resistors are used extensively as voltage-dependent resistors and are made by mixing small particles of silicon carbide with water, ceramic binder and / or conductive material, such as. B. graphite or metal powder, compressing the mixture in a mold to the desired shape and then drying and firing the compressed body in air or non-oxidizing atmosphere. Silicon carbide semiconductor resistors with conductive materials are characterized by a low electrical resistance, ie a low value for C and a low value for n, while silicon carbide semiconductor resistors without conductive materials have a high electrical resistance, ie a high value for C and a high value for .ι . It has been difficult to manufacture silicon carbide semiconductor resistors which are distinguished by a large η value and a small C value. For example, it is known that silicon carbide semiconductor resistors with graphite values from 2.5 to 3.3 and C values from 6 V to 13 V for a given current of 100 mA and silicon carbide semiconductor resistors without graphite have η values from 4 to 7 and C. -Values from 30 to 800 V at a given current of 1 mA door a

Sstäät.

10

P even size of the semiconductor _{resistance, for example of Ag n} J _1n diameter by 1 mm thickness.

Common rectifiers, which contain selenium or copper (I) oxide, have an n value of 5 to 10 and a pinene C value of less than 2 V for a given dittom of 100 mA and for the size of the sample concerned 20 mm in diameter. In this case, the thickness of the sample does not affect the C value. A germanium or silicon pn surface resistance has an extremely high n-value, but its ft value ^: ft constant, e.g. of the order of magnitude of 5Jg3 or 0.7 V at a given current of 100 mA, representing the diffusion voltage this resistance is constant according to the Strem-voltage characteristics and cannot be changed significantly. For iflprzielung _e i _nes suitable C value, it is necessary, I; f _everal diodes in series or parallel to be combined. However, the manufacturing process of such diodes is somewhat complicated and expensive. According to practical experience, the use of diode resistors is currently not widespread in view of the high cost, although the resistors may have a high η value.

A voltage-dependent resistor with a sintered body made of zinc oxide (ZnO) has become known from German patent specification 17 65 097, with an addition of bismuth oxide (Bi ₂ O ₃ ), niobium oxide, zirconium oxide (ZrO ₂ ) or tungsten oxide (WO ₃₎ ) and two on the opposite surfaces of the member of the group consisting of 0.05 to 6.0 weight percent cobalt oxide (CoO) and 0.05 to 6.0 weight percent manganese dioxide (MnO).

In a further embodiment, the bilber electrode has a composition consisting of 70 to 5 percent by weight silver, 0.3 to 27 percent by weight bismuth oxide (Bi ₁ O ₃ ), 0.03 to 15 percent by weight silicon dioxide (SiO ₂ ) and 0.05 to 15 percent by weight Percentage by weight of boron trioxide (B, O ₃ ). .

Finally, the silver electrode can also of at least one member of 005 to 6.0 weight percent cobalt oxide (CoO) and 0.05 to 6.0 weight percent manganese oxide (MnO) existing

Group exist. ,.

The drawing shows an embodiment of the voltage reduction characterized in the claims

gene resistances. , ...

A voltage-dependent resistor 10 contained! as an effective element, a sintered plate 1 made of electrically conductive ceramic material according to the

Invention. ...,. "

The sintered plate 1 is based on one described below Manner and is provided with a pair of electrodes 2 and 3 the s has certain compositions and aui one way described below on the two opposite surfaces of the plate.

Sk plate 1 is a sintered sheet and is exemplary

. _. . 1 · _i_ "Yes · - rar-htpr-ic IP li-

Sl.

The Aulgaoe aer the present invention is a voltage dependent resistance of the type mentioned at the beginning with a high n-value, an adjustable low C-value as well as high temperature, To provide moisture and electrical stability within a wide sintering temperature range.

According to the invention, this object is achieved by the following composition of the additives: 0.05 to 8.0 mol percent bismuth oxide (Bi ₂ O ₃ ) and 0.05 to 10.0 mol percent of at least one member of niobium oxide (Nb ₂ O ₅ ), zirconium oxide (ZrO ₂ ), tungsten oxide (WO ₃ ) and also vanadium oxide (V ₂ O ₅ ) and in that the particle size of the solid constituents of the at least one burned-in silver electrode (2 and / or 3) is in the range of 0.1 until 5 μπι was set.

One embodiment of the invention is characterized in that one of the electrodes is burned in Silver electrode and the other is an ohmic electrode.

Another embodiment is characterized by the following composition of the additives: 0.1 to 3.0 mol percent bismuth oxide (Bi ₂ O ₃ ) and 0.1 to 3.0 mol percent of at least one member of niobium oxide (Nb ₂ O ₅ ), zirconium oxide (ZrO ₂ ), vanadium oxide (V ₂ O ₅ ) and tungsten oxide (WO ₃ ).

Another embodiment is characterized in that the silver electrode has a composition consisting of 70 to 99.5 percent by weight silver, 0.3 to 27 percent by weight lead oxide (PbO), 0.1 to 15 percent by weight silicon oxide (SiO ₂ ) and 0.05 up to 15 percent by weight boron trioxide (B ₂ O ₃ ).

In another embodiment, the sintered electrode also consists of at least one

The sintered plate. ~.

Proverbs 1 and 3 mentioned substances.

It has been found that the sintered plate 1 has better non-linearity in terms of electrical Has properties when it is provided with silver electrodes that are created by applying silver paint on at least one of the opposite surfaces of the body 1 and firing at 300 to 850 ° C in an oxidizing atmosphere, such as. B. air and oxygen have been produced. the η value and the C value of the voltage-dependent Resistances vary with the compositions of the sintered plate and the Electrodes and their manufacturing process.

Because the non-linearity of the resistance is due to a non-ohmic contact between the sintered plate 1 and the electrodes 2 and 3, it is necessary to achieve an advantageous C-value and η value, the compositions of the sintered plate 1 and de ^r electrodes 2 and 3 to adjust. The adjustment of the C value and the n value can also be achieved by attaching an ohmic electrode as electrode 3 in place of the silver electrode.

To achieve a low C value for the voltage-dependent resistances, it is necessary to that the sintered plate has an electrical resistance of less than 10 ohm cm, which is electrical resistance is measured in a conventional manner according to a four-pole method. A Voltage-dependent resistance with low · C value and high η value can be obtained if the resistor is a sintered plate made of 82.0 to 99.9 mole percent zinc oxide (ZnO and the additives according to A. 1 and contains two electrodes that are on the opposite ^

Surfaces of said sintered plate attached at least one of these electrodes consists of a silver color electrode.

It has been found that the C-Wcrt is further reduced when one of the electrodes placed on the sintered plate, one silver color electrode and the other is an ohmic electrode.

The η value is further increased when the sintered plate is 94.0 to 99.8 mole percent zinc oxide and the Has additives according to A. 3.

The resistance to the electrical endurance test and the ambient temperature is also increased improved if the silver electrode has a composition as defined in claims 4, 5, 6 and 7 respectively.

The sintered plate 1 can be manufactured according to a method known per se in the field of ceramics. The starting materials for the compositions described above are mixed in a wet mill to form homogeneous mixtures. The mixtures are dried and pressed into the desired shape in a mold with a pressure of 9.81 MPa (MegaPascals) to 98.1 MPa. The pressed sheets are sintered in air at a temperature of 1100-1450 ⁰ C 1 to 3 hours then cooled from the temperature of the furnace to room temperature (about 15 to about 30 ° C). The pressed plates are preferably in a non-oxidizing atmosphere, such as. B. nitrogen or argon, sintered when it is desired to reduce the electrical resistance. The electrical resistance can also be reduced by air quenching from the sintering temperature to room temperature once the sintered plates have been fired in air.

The mixtures can precalcined to 1000 ⁰ C and then processed into a powder for easier handling in the subsequent pressing process first at 600th The mixture that is to be pressed can with a suitable binder, such as. B. with water, polyvinyl alcohol, etc., are mixed.

It is advantageous if the sintered plate on the opposite surfaces with abrasive powder, such as B. with silicon carbide with a particle size of 10 to 50 μτη diameter, ground or polished will.

The sintered plates are stained on one or both surfaces with a silver electrode paint usual way, such. B. by means of a spraying process, a printing process or a brushing process, overdrawn. Solid ingredients with the compositions described above can in a conventional manner by mixing commercially available powders with organic Resin, such as B. epoxy, vinyl or phenolic resin, in an organic solvent, such as. B. butyl acetate, poluene or the like., To be prepared so as to To win silver electrode colors.

The silver powder can be in the form of metallic silver or in the form of silver carbonate or silver oxide or in any other form that is used in the firing Temperatures converts to metallic silver. Hence the term "silver" included in this Description and claims in connection with the silver mass is used before it is fired, Silver in any form that is converted into metallic silver by firing. The viscosity the silver electrode colors obtained can be adjusted by the amounts of resin and solvent. It is also necessary to reduce the particle size of the solid components to a range from 0.1 to 5 μm to adjust.

The sintered plates with a silver electrode on only one of the surfaces of the body are made on the other surfaces with an ohmic electrode z. B. by means of the spray method using of Al, Zn and Sn, the vacuum evaporation method using Al, In and Zn or an electrolytic or electroless process using Ni, Cu and Sn.

Lead wires can be connected to the silver electrodes in a conventional manner using conventional Solder with a low melting point must be attached. It's easy to use a conductive adhesive, containing silver powder and resin in an organic solvent for connecting the lead wires to use with the silver electrodes.

The voltage-dependent resistors have a high resistance to temperature and during the endurance test. which is carried out at 70 C for an operating time of 500 hours. the The / ι-value and the C-value change according to the heating effects and the endurance test not noticeable. It is to achieve great persistence advantageous over moisture if the resistors obtained are in a moisture-proof resin such as z. B. epoxy resin and phenolic resin, are embedded in a conventional manner.

The method of hardening the applied silver electrode paint has a great influence on the value of the non-linear resistances obtained. The n-value is not optimal if the applied silver electrode paint is used for hardening in a non-oxidizing atmosphere, such as e.g. B. nitrogen and hydrogen is heated. To achieve a high n- value, it is necessary to remove the applied silver electrode paint by heating in an oxidizing atmosphere, such as, for. B. air and oxygen to harden.

Silver electrodes made by any process other than the silver color process lead to a bad n-value. For example, the sintered plate does not lead to one voltage-dependent resistance when they are on the opposite surfaces with silver electrodes has been provided by electroless plating or electrolytic plating in a conventional manner. Through Silver electrodes made by vacuum evaporation or chemical deposition lead to a 11 value less than 3.

The following examples serve to illustrate the preferred embodiments of the invention

example 1

Starting material according to Table 1 is mixed in a wet mill for 5 hours.

The mixture is dried and in a form with a pressure of 33.3 MPa (Mega Pascal) zi a plate with a diameter of 13 mm and a thickness of 2.5 mm.

The pressed plate is sintered in air for 1 hour at 1350 ^° C. and then quenched to room temperature (about 15 to about 30 ^° C.). The sintered plate is on the opposite surface! with the help of silicon carbide with a particle size

sanded from 600 meshes. The resulting sintered Plate has a size of 10 mm in diameter and 1.5 mm in thickness. The sintered plate is attached to the opposite surfaces with a silver electrode paint using conventional painting methods overdrawn. The silver electrode paint used has a solid component composition according to Table 2 and is prepared by mixing with vinyl resin in anylacetate. The coated plate will Fired in air at the temperature given in Table 2 for 30 minutes.

Lead wires are connected to the electrodes using silver paint. The electrical properties of the resistance obtained and of other resistors produced in the same way are shown in Table 1 given.

The resistances obtained have a low C-value and a high n-value (see Appendix

Tables 1 and 2). _,. . , "
Example 2

Starting material according to Table 3 is mixed in a wet mill for 5 hours. The mixture is dried, pressed, sintered and ground in the same manner as in Example 1. The honed Plate is placed on a surface with the same silver electrode colors as in the example 1 are used, coated by a conventional brushing method. The coated plate is fired in air at the temperature given in Table 2 for 30 minutes. The burned plate is applied to its other surface with an ohmic electrode by spraying aluminum or provided by vapor deposition of aluminum.

Lead wires are connected to the silver electrodes with the help of silver paint. The electric Properties of the resulting resistor and of other resistors manufactured in the same way are given in Table 3, the electrical properties being compared with those obtained by attaching a high voltage terminal the polarity applied to the silver electrode were measured.

The combination of silver electrodes and ohmic electrodes results in a low C value and a large η value (see Appendix, Table 3).

Example 3

A sintered plate having one shown in Table 4 is obtained in the same manner as in Example 1 Composition made. The sintered plate is 10 mm in diameter and 1.5 mm in size Thickness after sanding. Different colors of silver electrodes are applied to the opposing surfaces applied to the sintered plate and at the temperature listed in Table 4 for 30 minutes burned in air. The silver electrode colors have a composition given in Table 4 Solid ingredients and are made by mixing

ίο 100 parts by weight of the said compositions prepared from solid ingredients with 1 to 20 parts by weight of epoxy resin in 20 to 40 parts by weight of butyl alcohol. The resistances obtained have advantageous C values and n values, as indicated in Table 4. It is easy to see that the electrode compositions have a great influence on the electrical characteristics of the resulting variable voltage resistors and that especially electrode compositions containing cobalt oxide and manganese oxide are advantageous for obtaining a high value (see Appendix, Table 4).

Example 4

Resistors are produced in the manner described in Example 1 from a sintered plate with a composition given in Table 5. The resistors are tested according to the procedures used for parts with electronic components. The endurance test is carried out at an ^{ambient temperature of 70 °} C. and at 1 watt over a period of 500 hours. The test with repeated heating sequences is carried out by repeating a sequence five times in which the said resistors are held at 85 ° C. ambient temperature for 30 minutes, cooled rapidly to -20 "C., and then held at this temperature for 30 minutes Amounts of change for the C value and the η value obtained after the heating sequence and load duration test are shown in Table 5. It is easy to see that the amounts of change are less than 10% and, in particular, the compositions of the silver electrodes, which contain cobalt oxide and manganese oxide cause excellent resistance (see Appendix, Table 5).

Table 1

Bi ₂ O ₃

99.90 0.05 89.95 0.05 91.95. 8th 8Z0 8th 99.8 0.1 96.9 0.1 96.9 3 94.0 3 99.0 0.5 99.90 0.05

Another addition 0.05 Silver color A π 6.0 Silver color B 8.0 609 615/11 10 C. 5.8 C. 8.1 (Mole percent) 0.05 (at 100 mA) 5.7 (at 10OmA) 7.9 Nb ₂ O ₅ 10 4.0 6.0 6.1 8.0 Nb ₂ O ₅ 0.1 3.9 7.1 5.9 12th Nb ₂ O ₅ 3 4.2 7.3 6.0 13th Nb ₂ O ₅ 0.1 4.1 7.5 5.8 10 Nb ₂ O ₅ 3 3.4 7.4 5.0 12th Nb ₂ O ₅ 0.5 3.2 10 4.8 18th Nb ₂ O ₅ 0.05 3.3 4.8 5.1 6.0 Nb ₂ O ₅ 3.1 4.9 Nb ₂ O ₅ 2.8 4.0 ZrO ₂ 4.2 5.9

10

continuation

Bi ₂ U, Another addition 10 Silver color A. 4.7 0.05 C. 4.9 Mole percent) (Mole percent) (Mole percent) 10 (at KX) mA) 4.9 89.95 0.05 ZrO ₂ 0.1 4.1 7.1 91.95 8th ZrO ₂ 3 4.6 6.9 82.0 8th ZrO ₂ 0.1 4.3 7.7 99.8 0.1 ZrO ₂ 3 3.5 7.0 96.9 0.1 ZrO ₂ 0.5 3.5 9.0 96.9 3 ZrO ₂ 0.05 3.6 6.0 94.0 3 ZrO ₂ 10 3.4 5.9 99.0 0.5 ZrO ₂ 0.05 3.0 5.8 99.90 0.05 V ₂ O ₅ 10 3.9 5.9 89.95 0.05 V ₂ O ₅ 0.1 4.0 7.3 91.95 8th , V ₂ O ₅ 3 4.1 7.1 82.0 8th V ₂ O ₅ 0.1 4.0 7.2 99.8 0.1 V ₂ O ₅ 3 3.2 7.2 96.9 0.1 V ₂ O ₅ 0.5 3.3 9.5 96.9 3. . V ₂ O ₅ 0.05 3.2 6.8 94.0 3 V ₂ O ₅ 10 3.3 6.7 99.0 0.5 V ₂ O ₅ 0.05 2.8 6.5 99.90 0.05 WHERE ₃ 10 6.0 6.4 89.95 0.05 WHERE ₃ 0.1 5.9 ' 7.9 91.95 8th WHERE ₃ 3 5.7 8.0 82.0 .8th WHERE ₃ 0.1 5.9 8.1 99.8 0.1 WHERE ₃ 3 3.9 8.0 96.9 0.1 WHERE ₃ 0.5 4.0 11th 96.9 3 WHERE ₃ 0.1
0, 4.1 12th 94.0 3 ^::; WHERE ₃ 0,
0.1 4.0 12th 99.0 0.5 WHERE ₃ O, ¹
0, 3.5 13th 99.3 o, - j [Nb ₂ O ₅
IZrO ₂ 0.1
0.1 2.6 12th 99.3 ° · ⁵ : J [Nb ₂ O ₅
V ₂ O ₅ 0.1
0.1 2.7 12th 99.3 0.5. Nb ₂ O ₅
WHERE ₃ 2.8 13th 99.3 ■ 05 y [ZrO ₂
IV ₂ O ₅ 2.8 99.3 I. [ZrO ₂
LWO, 2.8 14th 99.3 0.5: [V ₂ O ₅
IWO ₃ 2.8 Nb ₂ O ₅ 99.2 0.5 ZrO ₂ 0.1
0.1 2.2 13th V ₂ O ₅ 0.1 Nb ₂ O ₅ 0.1 99.2 0.5 ZrO ₂ 0.1 2.3 14th WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 99.2 0.5 V ₂ O ₅ 0.1 2.3 14th WHERE ₃ 0.1 ZrO ₂ 0.1 99.2 0.5 V ₂ O ₅ 0.1 2.5 WHERE ₃ 0.1 0.1 0.1

Silver color B ff 6.6 C. 6.4 (at KX) mA) 6.5 5.7 Il 6.0 11th 5.6 10 4.8 10 4.6 17th 4.7 9.0 4.6 9.0 4.8 9.2 5.9 8.9 5.8 10 6.2 11th 6.0 12th 5.3 12th 5.1 16 5.3 8.5 5.1 8.6 4.1 8.1 8.0 8.4 8.1 11th 7.9 11th 7.9 11th 5.8 12th 5.9 18th 6.0 20th 6.1 20th 5.0 21 3.9 10 3.8 20th 4.1 20th 4.0 4.5 3.8

3.0 3.2 3.7 3.9

11th

12th

continuation Bi ₂ O., Another addition 0.1 Silver color A Silver color B ZnO 0.1 C Ii C η (Mole percent) (Mole percent) 0.1 (at KK) mA) (at 10OmA) ! Mole percent) Nb ₂ O ₅ 0.1 0.5 ZrO ₂ 2.0 15 2.8 26 99 1 V ₂ O ₅ WHERE,

Table 2

Silver color Firing temperature Ag ("C) (G. A. 500 90 B. 800 90

PbO

Bi ₂ O.,

SiO,

(Percent by weight) (percent by weight) (percent by weight) (percent by weight) (percent by weight)

Table 3

ZnO Bi ₂ O ₃ Another addition 0.05 Silver color A 9.0 Silberrarbc B 10 10 C. 9.1 C. 11th (Mole percent) (Mole percent) (Mole percent) 0.05 (at lOOniA) 9.0 (at 100 mA) 10 99.90 0.05 Nb ₂ O ₅ 10 0.62 8.9 0.85 10 89.95 0.05 Nb ₂ O ₅ 0.1 0.61 11th 0.83 15th 91.95 8th Nb ₂ O ₅ 3 0.63 10 0.82 14th 82.0 8th Nb ₂ O ₅ 0.1 0.64 11th 0.83 14th 99.8 0.1 Nb ₂ O ₅ 3 0.59 11th 0.79 15th 96.9 0.1 Nb ₂ O ₅ 0.5 0.60 13th 0.78 21 96.9 3 Nb ₂ O ₅ 0.05 0.60 8.5 0.79 9.0 94.0 3 Nb ₂ O ₅ 10 0.59 8.7 0.77 9.0 99.0 0.5 Nb ₂ O ₅ 0.05 0.57 9.0 0.72 8.8 99.90 0.05 ZrO ₂ 10 0.67 8.6 0.90 8.9 89.95 0.05 ZrO ₂ 0.1 0.68 9.3 0.89 11th 91.95 8th ZrO ₂ 3 0.67 9.4 0.88 Π 82.0 8th ZrO ₂ 0.1 0.70 9.8 0.90 12th 99.8 0.1 ZrO ₂ 3 0.65 9.9 0.82 14th 96.9 0.1 ZrO ₂ 0.5 0.63 12th 0.83 19th 96.9 3 ZrO ₂ 0.05 0.64 8.4 0.84 10 94.0 3 ZrO ₂ 10 0.63 8.5 0.85 10 99.0 0.5 ZrO ₂ 0.05 0.60 8.0 0.78 11th 99.9 0.05 V ₂ O ₅ 10 0.73 8.7 0.95 ro 89.95 0.05 V ₂ O ₅ 0.1 0.73 10 0.92 14th 91.95 8th V ₂ O ₅ 3 0.71 11th 0.91 14th 82.0 8th V ₂ O ₅ 0.1 0.72 10 0.93 15th 99.8 0.1 V ₂ O ₅ 3 0.69 10 0.88 14th 96.9 0.1 V ₂ O ₅ 0.5 0.68 13th 0.87 20th 96.9 3 V ₂ O ₅ 0.05 0.68 8.5 0.87 Π 94.0 3 V ₂ O ₅ 10 0.69 8.7 0.88 11th 99.0 0.5 V ₂ O ₅ 0.65 0.81 99.90 0.05 WHERE ₃ 0.90 1.03 89.95 0.05 WHERE ₃ 0.89 1.00

13th

14th

continuation

Bi, O,

91.95 8th 82.0 8th 99.8 0.1 96.9 0.1 96.9 3 94.0 3 99.0 0.5 99.3 0.5 99.3 0.5 99.3 0.5 99.3 0.5 99.3 0.5 99.3 0.5

0.5 0.5 0.5 0.5

0.5

Further assistance / 0.05 Silver color Λ 8.5 (Molpro / cnt) 10 (
(at K) OmAI 8.5 WHERE ₃ 0.1 0.88 10 WHERE ₃ 3 0.90 10 WHERE ₃ 0.1 0.85 11th WHERE ₃ 3 0.83 10 WHERE ₃ 0.5 0.82 12th WHERE ₃ 0.1 0.84 16 WHERE ₃ 0.1 0.75 / Nb ₂ O ₅ 0.1 0.63 16 IZrO ₂ 0.1
0.1 17th [Nb ₂ O ₅
W ₂ O ₅ 0.1
0.1 0.60 16 / Nb ₂ O ₅
IWO ₃ 0.1 0.61 / ZrO ₂
W ₂ O ₅ 0.1 0.63 17th IZrO ₂ 0.1
0.1 18th IWO ₃ 0.1 0.65 / V ₂ O ₅
IWO ₃ 0.1 0.65 19th (Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 0.57 Iv ₂ O ₅ 0.1 19th Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 0.60 WHERE ₃ 0.1 20th Nb ₂ O ₅ 0.1 V ₂ O ₅ 0.1 0.61 WHERE ₃ 0.1 21 (ZrO ₂ 0.1 V ₂ O ₅ 0.1 0.61 IWO ₃ 0.1 Nb ₂ O ₅ 0.1 24 ZrO ₂ 0.1 V ₂ O ₅ 0.62 WHERE,

Silver color B ;; C. (at KX) mA) 10 0.97 K) 0.99 14th 0.95 15th 0.96 16 0.97 15th 0.95 21 0.92 23 0.72 22nd 0.75 23 0.85 22nd 0.74 23 0.87 23 0.88

0.73

0.87

0.78

26th

0.83 24

0.85

30th

Table 4 Sintered body Silver color ZnO Bi ₂ O, further addition of fuel Ag PbO Bi ₂ O ₃ SiO ₂

temp. (Mole percent) (C) (weight percent)

CoO

MnO

Electrical characteristics C "

(at 100 mA)

99.1 0.5

Nb ₂ O ₅ ZrO ₂ V ₂ O ₅ WO ₃

0.1 0.1 0.1 0.1

500

6 -

2.2

/ ZO

15th

16

continuation

Sintered body

Silver color

ZnO Bi ₂ O ₃ additional fuel Ag PbO Bi ₂ O,

temp.

(Mole percent) ("C) (weight percent)

CoO

MnO

Electrical characteristics

(at 100 mA)

99.1 0.5 99.1 0.5 99.1 0.5 99.1 0.5 99.1 0.5 99.1 0.5 99.1 0.5

Table 5

Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE, 0.1

800 90 -

750 80 -

650

550 90

800

800

800 90 -

12th

18 3.0 28

3.5 25

3.9 21

2.5 14

2.7 28

1 3.0 28 0.5 0.5 2.6 30

Sintered body Bi ₂ O ₃ 0.5 further additions 0.5 Silver color Ag PbO Bi ₂ O., SiO ₂ 6-2 B ₂ O, CoO Mn ZnO 0.5 0.5 Burning 6-2 Mole percent) 0.5 0.5 temp. (Weight percent) 6 - 2 99.0 0.5 Nb ₂ O ₅ 0.5 (C) 90 6 2 2 99.0 ZrO ₂ 0.1 500 90 2 99.0 0.5 V ₂ O ₅ 0.1
0.1 500 90 6 2 2 _ 99.0 WHERE ₃ 0.1 500 90 2 Nb ₂ O ₅ 0.1 500 99.1 0.5 ZrO ₂
V ₂ O ₅ 0.1 90 6 2 2 ._ WHERE ₃ 0.1 500 Nb ₂ O ₅ 0.1 99.1 ZrO ₂ 90 2 V ₂ O ₅ 800 WHERE,

Load-warming endurance test, follow-up test

ChCm (Vo) (Vo) (%) 1%)

-6.3 -7.1 -5.9 -4.3

-6.8 -6.2 -6.0 -4.8

-7.2 -6.0 -4.2 -5.0

-8.0 -6.8 -4.8 -4.8

2.2 -1.8 -2.5 -1.5

-2.3 -2.0 -3.0 -1.9

Arv) Αλ ς / ι

17th

18th

continuation Sintered body

Silver color Belaslungslastiesl

ZnO Bi ₂ O ₃ further additives fuel Ag PbO Bi, O < SiO, B ₂ O ₃ CoO MnO C

lemp.

mole percent) (C) (weight ^{per cent <%}

Warming Consequencesi

99.1

99.1

99.1

Nb ₂ O ₅ 0.1 I 0.5 ZrO ₂
V ₂ O ₅ 0.1
0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 I 0.5 ZrO ₂
V ₂ O ₅ 0.1
0.1 WHERE ₃ 0.1 Nb ₂ O ₅ ο, ΐ 05 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 0.5 ZrO ₂
V ₂ O ₅ O, I.
0.1 WHERE ₃ 0.1 Nb ₂ O ₅ 0.1 0.5 ZrO ₂ 0.1 V ₂ O ₅ 0.1 WHERE ₃ ο, ι

800 90

800 90

800 90

750 80

650 70 2 1

2 1

-611

-1.0 -1.1 -1.5 -1.0

-0.9 -0.9 -1.2 -0.9

-0.5 -0.9 -0.8 -0.7

- 12 4 4 - - -7.8 -8.0 -7.9 -6.8 6 6

-9.0 -9.1 -7.4 -8.6

1 sheet of drawings

Claims (7)

Patent claims: 1. Voltage-dependent resistor made of a sintered plate which consists essentially of zinc oxide and which also contains small amounts of other oxides, namely at least one of the oxides from a group of compounds consisting at least of bismuth oxide, niobium oxide, zirconium oxide and tungsten oxide, and with two electrodes attached to the opposite surfaces of the plate, at least one of which consists of a burnt-in silver electrode, characterized by the following composition of the additives: 0.05 to 8.0 mol percent bismuth oxide (Bi ₂ O ₃ ) and 0.05 to 10, 0 mol percent of at least one member of the group consisting of niobium oxide (Nb ₂ O ₅ ), zirconium oxide (ZrO ₂ ), tungsten oxide (WO ₃ ) and also vanadium oxide (V ₂ O ₅ ) and in that the particle size of the solid constituents of at least one Burned-in SilberelekiTode (2 and / or 3) was set to a range from 0.1 to 5 μΐη. 2. Voltage-dependent resistor according to claim 1, characterized in that the one of the electrodes (2, 3) is a burnt-in silver electrode and the other is an ohmic electrode. 3. Voltage-dependent resistor according to claim 1, characterized by the following composition of the additives: 0.1 to 3.0 mol percent bismuth oxide (Bi ₂ O.) and 0.1 to 3.0 mol percent of at least one member of niobium oxide (Nb ₂ O.) ₅ ), zirconium oxide (ZrO ₂ ), vanadium oxide (V ₂ O ₅ ) and tungsten oxide (WO ₃ ). 4. Voltage-dependent resistor according to claim 1, characterized in that the silver electrode has a composition consisting of 70 to 99.5 percent by weight silver, 0.3 to 27 percent by weight lead oxide (PbO), 0.1 to 15 percent by weight silicon dioxide ( SiO ₂ ) and 0.05 to 15 percent by weight boron trioxide (B ₂ O ₃ ). 5. Voltage-dependent resistor according to claim 4, characterized in that the silver electrode additionally from at least one member of 0.05 to 6.0 percent by weight Cobalt oxide (CoO) and 0.05 to 6.0 percent by weight manganese dioxide (MnO) consists. 6. Voltage-dependent resistor according to claim 1, characterized in that the silver electrode has a composition consisting of 70 to 99.5 percent by weight silver, 0.3 to 27 percent by weight bismuth oxide (Bi ₂ O ₃ ), 0.03 to 15 percent by weight silicon dioxide ( SiO ₂ ) and 0.05 to 15 percent by weight boron trioxide (B ₂ O ₃ ). 7. Voltage-dependent resistor according to claim 6, characterized in that the silver. electrode also made of at least one member of 0.05 to 6.0 percent by weight Cobalt oxide (CoO) and 0.05 to 6.0 percent by weight manganese dioxide (MnO) consists. 65 The invention relates to a voltage-dependent Resistance from a sintered plate, which essentially consists of zinc oxide and which also has it Contains minor amounts of other oxides, at least one of the oxides from one A group of compounds consisting at least of bismuth oxide, niobium oxide, zirconium oxide and tungsten oxide, and with two electrodes placed on the opposite surfaces of the plate, at least one of which consists of a burned-in silver electrode. Such a resistor is known from GB-PS 11 30 108 Numerous voltage-dependent resistors, such as silicon carbide semiconductors, selenium or copper (I) oxide rectifiers and germanium or silicon pn surface rectifiers, are also known. The electrical properties of such voltage-dependent Resistances are given by the equation