DE1802452C - Voltage-dependent mass resistance and method for its manufacture - Google Patents

Description

This invention relates to voltage dependent resistors having a non-Ohmic resistance Because of their mass and especially varistors that contain zinc oxide and bismuth oxide, and the manufacturing process of resistances.

Various voltage-dependent resistors, such as silicon carbide varistors, selenium rectifiers or Germanium or silicon pn junction diodes widely used to stabilize voltage or current in electrical circuits. The electrical characteristics of such a voltage-dependent resistor are given by the equation

I.

expressed, where V is the voltage across the resistor, / the current flowing through the resistor. C is a constant corresponding to the voltage at a given current and the exponent η

numeric value is greater than 1. The value of / i is calculated according to the following equation:

where V ₁ and V _{2 are} the voltage at given currents 7 and I ₂ , respectively. The desired value of C depends on the type of application for which the resistor is required. It is usually desirable that the value of η be as large as possible because this expo-!. nt defines the degree to which the resistances ■ ·. ; p deviate from the ohmic characteristics.

: '. s have already proposed non-linear resistors -... propose (German Patent 1 665 135), the ..U-. ,! i.itzen sintered bodies of zinc oxide with or without, such as bismuth oxide, cobalt oxide and AIu- ''. ':; .- uiumoxid, consist, on which are applied Silberfarbenelekiden The non-linearity of such varistors is the interface between the Gesin ertön body. of zinc oxide with or without additives iv.d to the silver color electrode and The sintered body has ohmic structures and requires a specific electrical resistance which is less than 10 ohm-cm. Therefore, it is not easy to control mi C over a wide range. :: iwhich the sintered body is made. Similarly, varistors comprising germanium or silicon nn area diodes are very difficult to control in the C value over a large range, since the non-linearity is not due to the ground but to the pn junction. On the other hand, the silicon carbide varistors have a non-linearity due to the contacts between the individual grains of silicon carbide which are bonded together by a ceramic binder, i.e. due to the mass, and they are controlled in C-value by taking a dimension in one direction, in which the current flows through the varistors is changed. The silicon carbide varistors, however, have a relatively low η value between 3 and 6 and are produced by annealing in a non-oxidizing atmosphere, in particular in order to obtain a lower C value.

There are known resistors which consist of a zinc oxide sintered plate with two electrodes attached to the opposite surfaces thereof, e.g. From U.S. Pat. No. 2,887,632. U.S. Pat. No. 2,887,632 teaches resistors with a low resistivity, but the resistors have ohmic rather than voltage dependent properties. British Patent 731,372 proposes ceramic materials containing zinc oxide and other additives. British Patent 731,372 relates to a low voltage ignition system and ceramic material used for a semiconductor resistor, but does not teach a block voltage dependent resistor and does not provide for the use of Bi as an additive. ^ft 5

The present invention was based on the object a voltage-dependent resistor with a due to the block shape of the same Develop stress non-linearity, which is characterized by a high η value.

The subject of the invention is a voltage-dependent resistor, which is characterized in that the resistance from a sintered body in a composition consisting essentially of 80.0 to 99.9 mole percent zinc oxide, 0.05 to 10 mole percent Bismuth oxide and a total of 0.05 to 10.0 mol percent of at least one oxide from the group: cobalt oxide, Manganese oxide, indium oxide, antimony oxide, titanium oxide, borium oxide, aluminum oxide, tin oxide, barium oxide, Nickel oxide, molybdenum oxide, tantalum oxide, iron oxide and chromium oxide, is formed, and on opposite sides Ohmic electrodes are attached to the surfaces of this sintered body.

Such a voltage-dependent resistor has a non-ohmic one because of its block shape Resistance. Therefore, its C value can be changed without deteriorating the »value if one changes the distance between said opposing surfaces. A shorter resistance leads to a lower C-value.

One embodiment of the invention consists in that the sintered body has a composition consisting essentially of 94.0 to 99.8 mole percent zinc oxide, 0.1 to 1.0 mole percent bismuth oxide and a total of 0.1 to 5.0 mol percent of at least one oxide from the group: cobalt oxide, manganese oxide, Iridium oxide, antimony oxide, titanium oxide, boron oxide, aluminum oxide. Tin oxide, barium oxide, nickel oxide, Molybdenum oxide, tantalum oxide, iron oxide and chromium oxide. Advantageous about this voltage-dependent Resistance is that a higher ii value can be obtained.

Another embodiment of the invention consists in that the ohmic electrodes consist of a member of the group: electrolytically or electrolessly plated film of Ag, Cu, Ni, Zn and Sn, im Contains vacuum deposited film of Ag, Zn, Sn and In and metallized film of Cu, Zn, Sn and Al. The advantage of this voltage-dependent resistor is that it has a stable ohmic electrode can thereby be obtained.

A further embodiment of the invention consists in that the sintered body consists essentially of 85.00 up to 99.85 mole percent zinc oxide, 0.05 to 5.0 mole percent bismuth oxide, 0.05 to 5.0 mole percent cobalt oxide or manganese oxide and a total of 0.05 to 10.0 mol percent of at least one oxide from the group: Boric oxide, barium oxide, indium oxide, antimony oxide, titanium oxide and chromium oxide. Advantage of this voltage-dependent resistance is that the n-value can be increased further.

Another preferred embodiment of the present invention is that a sintered body consisting essentially of 84.00 to 99.80 mole percent zinc oxide, 0.05 to 5.00 mole percent bismuth oxide, 0.05 to 3.00 mole percent cobalt oxide, 0.05 to 3.00 mole percent manganese oxide, and 0.05 total up to 5.00 M oil percent of at least one oxide from the group: boron oxide. Barium oxide, indium oxide. Antimony oxide, Titanium oxide and chromium oxide. The advantage of this voltage-dependent resistor is that the value can be increased noticeably.

A further embodiment of the invention consists in a method for producing a voltage-dependent Resistance at which a sintered grain of zinc oxide is presented. the eesenüher-

The lying surfaces of this sintered body are coated with a paste that contains bismuth oxide in finely divided powder form as a solid component, the coated body is ^{heated at a temperature of 600 to 1200 0} C in an oxidizing atmosphere so that bismuth ions diffuse into the mass of this sintered body, and that with bismuth diffused body cools to room temperature. This method allows to improve the value and the stability with temperature, humidity and electrical loads.

A preferred embodiment of the invention consists in a method for producing the voltage-dependent resistor, in which a sintered body made of zinc oxide with or without a total of 0.1 to 5.0 mol percent of at least one oxide from the group: cobalt oxide, manganese oxide, indium oxide, antimony oxide, titanium oxide , Boron oxide, aluminum oxide, tin oxide, barium oxide, nickel oxide, molybdenum oxide, tantalum oxide, iron oxide and chromium oxide, the opposite surfaces of this sintered body are coated with a paste that contains bismuth oxide powder as a solid component, the coated body at a temperature of 600 to 120O ⁰ C is fired in an oxidizing atmosphere, so that bismuth ions diffuse into the mass of the sintered body, and the sintered body diffused with bismuth is cooled to room temperature. The advantage of this embodiment is that the Η value and the stability are further improved.

Another preferred embodiment of the invention consists in a method for producing the voltage-dependent resistor, in which the paste contains 20 to 80 percent by weight bismuth oxide in finely divided powder form as a solid component and the remainder consists of at least one compound from the group of Koba ¹ · and manganese compounds. The advantage of this process is that the η value and the stability can be markedly improved.

Finally, a further embodiment of the invention consists in the fact that this paste is a fixed component contains powdered glass frit in a composition consisting essentially of 48 to 80 percent by weight Bismuth oxide, 8 to 23 percent by weight boron oxide, 8 to 23 percent by weight silicon dioxide, total 4 to 16 percent by weight of at least one oxide from the group: cobalt oxide and manganese oxide, consists. The advantage of this process is that it has optimal properties with regard to the value and keep the stability.

These and other objects of the invention will become apparent from the following description taken in conjunction with FIG Drawing become clear, in which the only figure is a Tcil cross section through a stress-dependent Resistance according to the invention.

Before proceeding with a detailed description of the voltage-dependent resistors according to the invention is started, the construction thereof will be carried out with reference to the above figure of the drawing ho described, wherein the reference numeral 10 denotes a voltage-dependent resistor as a whole, who as its active element a sintered body with a pair of electrodes 2 and 3 in ohnischiMTi Contact on opposite surfaces h.s. of the body. The sintered body 1 is manufactured in a manner described below and has some form. d. i.e., it is /. B.

around a circular, square or rectangular plate. Lead wires 5 and 6 are conductive to the Electrodes 2 or 3 by a connecting means 4 such as solder or the like.

The sintered body 1 can be produced by the ceramic technique which is well known per se. The starting materials in the compositions as described above are mixed in a wet mill to produce homogeneous mixtures. The mixtures are dried and pressed in a compression mold into the desired shapes at a pressure of from 100 to 1000 kg / cm ² . The pressed bodies are sintered in air at a given temperature for 1 to 3 hours and then ^{cooled in the furnace to room temperature (about 15 to about 30 °} C.).

The sintering temperature is determined taking into account the electrical resistance value, the non-linearity and the stability. The sintered body of zinc oxide with bismuth oxide as the sole additive is preferably annealed at a temperature of 800 to 1200 ⁰ C. The body sintered at a temperature above 1200 ^° C. shows a low specific electrical resistance and a poor non-linearity. With regard to the above-mentioned sintered body made of zinc oxide with a combined addition of bismuth oxide and at least one metal oxide selected from the group consisting of cobalt oxide, manganese oxide, indium oxide, antimony oxide, titanium oxide, boron oxide, aluminum oxide, tin oxide, barium oxide, nickel oxide, molybdenum oxide, tantalum oxide, iron oxide and chromium oxide is the preferable annealing temperature in the range of 1000-1450 ⁰ C.

The specific electrical resistance can also be reduced by relying on the sintering temperature is quenched to room temperature in air even when the pressed bodies are annealed in air. The mixtures can be calcined beforehand at 700 to 1000 ° C. and subsequently for easy processing Pulverized pressing step. The mixture to be pressed can be a suitable binder, such as Water, polyvinyl alcohol can be added.

It is advantageous if the sintered body on the opposite surfaces with abrasive powder, like silicon carbide in with particles the size of which passes through a sieve with a mesh size of go through, is lapped.

The sintered bodies are provided with the above on their opposing surfaces ohmic electrodes are provided in any available and suitable manner.

Lead wires can be connected to the silver electrodes in a manner known per se using a conventional low melting point solder. Conveniently becomes a senior Uses glue that contains silver powder and a resin in an organic solvent to make the Connect lead wires to the silver electrodes.

Voltage-dependent resistances according to this Invention have high stability with the Tem temperature and in the endurance test under load, which at 70'C at the rated output 500 hours is carried out for a long time. The η value and the C value do not change noticeably after warming up and the endurance test under load. To achieve a high moisture stability are the

resulting non-linear resistances preferably in a moisture-impermeable resin such as Epoxy resin and phenolic resin embedded in a manner well known per se.

A more preferred method for producing a voltage-dependent resistor, which can be proposed according to the invention, is that a sintered body of zinc oxide with or without a total of 0.1 to 5.0 mol percent of at least one oxide from the group: cobalt oxide, manganese oxide, indium oxide, antimony oxide , Titanium oxide, boron oxide, aluminum oxide, tin oxide, barium oxide, nickel oxide, molybdenum oxide, tantalum oxide, iron oxide and chromium oxide, pretends to coat the opposite surfaces of this sintered body with a paste that contains bismuth oxide powder as a solid component, the coated body at a temperature of 600 Burns up to 1200 ° C in an oxidizing atmosphere, so that bismuth ions diffuse into the mass of this sintered body, the bismuth-diffused sintered body cools to room temperature, and the above-mentioned ohmic electrodes are attached to opposite surfaces of the finished body. The sintered body according to per se well-known ceramic technology are made, that is, by heating of a pressed body of a given composition at a temperature of 1000-1450 ⁰ C for 1 hour in air or non-oxidizing atmosphere such as nitrogen gas or argon gas.

The paste contains as a solid component bismuth oxide powder and an organic resin such as epoxy, vinyl and phenolic resin in an organic solvent such as butyl acetate, toluene od Heating to 600 to 1200 ⁰ C is converted into bismuth oxide. Possible weight proportions of bismuth oxide to the organic solution are 20 to 80 percent by weight bismuth oxide and the remainder organic binder. According to the invention, it has been discovered that the n-value is extremely increased when bismuth oxide is contained as a solid component of the paste together with cobalt oxide and / or magnesium oxide. Workable and preferred weight proportions of the solid ingredients are shown in Table 1.

Table 1

Feasible
Proportion ..

Preferred
proportion

Bismuth oxide

2-8
2-8

2-8

Weighted part
Cobalt oxide

2-8

1-2

Manganese oxide

2-8

1-2 weight percentages of the glass frit are shown in Table 2.

Table 2

5 Feasible Bi ₂ O ₃ B ^ O ₃ SiO ₂ CoO MnO Weight ₀ percent 50-84 8-25 8-25 - - 48-80 8-23 8-23 4-16 - Preferred 48-80 8-23 8-23 - 4-16 Weight ■ 5 percent 40-70 10-20 10-20 5-10 5-10

The cobalt oxide and manganese oxide can be in ! in the form of metallic cobalt and metallic manganese or in any other form of compound are present, which, when annealed in oxide, at the. · .endend Temperature is converted. A very / u preferred tester ingredient is finely divided Glass frit containing bismuth oxide, cobalt oxide and / or manganese oxide. Feasible and Preferred

The powdered glass frit is in an organic solvent such as butyl acetate, toluene or the like. which dissolves organic resin such as epoxy, vinyl and phenolic resin. Care must be taken that The glass frit does not contain any alkali metal ions in a monovalence, such as lithium ions, potassium ions or Sodium ions. Workable percentages by weight of a preferred paste are 20 to 60 percent by weight Powdered glass frit, 20 to 40 percent by weight organic resin and 20 to 40 percent by weight organic solvent.

The diffusion temperature and the diffusion time depend on the weight percentage of bismuth oxide in the paste and should be controlled so that the diffused bismuth oxide diffuses uniformly in the throughout the sintered body of zinc oxide and constitutes an amount of 0.1 to 1.0 mole percent. A higher diffusion temperature requires a shorter diffusion time.

Such a diffusion technique produces a sintered body with an η value higher than that of a sintered body made by adding a mixture of 99.9 to 99.0 mole percent Zinc oxide and 0.1 to 1.0 mole percent bismuth oxide or from 99.8 to 94.0 mole percent zinc oxide, 0.1 to 1.00 mole percent bismuth oxide and 0.1 to 5.0 mole percent of at least one oxide from the group: cobalt oxide, Manganese oxide, indium oxide, antimony oxide, titanium oxide, borium oxide, aluminum oxide, tin oxide, barium oxide, Nickel oxide, molybdenum oxide, tantalum oxide, iron oxide and chromium oxide sinters.

example 1

The starting materials shown in Table 3 are mixed in a wet mill for 5 hours.

The mixture is dried and in a mold

pressed into a disc 13 mm in diameter and 2.5 mm thick with a pressure of 340 kg / cm ^2.

The pressed body is sintered in air at the temperature shown in Table 3 for 1 hour and then cooled in the oven to room temperature (about 15 to about 30 ° C). The sintered disc is applied to the thickness shown in Table 3 on the opposite surfaces by means of a silicon carbide abrasive with particles that pass through a sieve with a mesh size of mm, lapped. The opposite surfaces of the sintered disc are spray-metallized with a Aluminum film provided according to known technology. Lead wires are on the aluminum electrodes with the help of a

conductive silver paint attached. Dielectric properties of the resulting resistor are shown in Table 3. It is easy to see that the C value changes proportionally with the thickness of the sintered body. The preferred sintering temperature for the sintered body made of zinc oxide containing bismuth oxide is between 800 and 1200 ^° C.

Table 3 Table 4

Raw materials
(Mole percent)

ZnO Bi ₂ O ₃ 99.8 0.2 99.8 0.2 99.8 0.2 99.8 0.2 99.8 0.2 99.8 0.2 99.8 0.2 99.8 0.2 99.8 0.2 99.95 0.05 99.9 0.1 99.5 0.5 99.0 1.0 95.0 5.0

Sinter
temperalur thickness Electric Eij.
shafts of fer
Resistance "
C. cn-
igen CC) (mm) (at a
given current
of 1 mA) Il 750 1.0 200 1.8 800 1.0 81 3.2 1000 1.0 43 4.3 1150 1.0 44 4.2 1300 1.0 0.3 U 1000 2.0 84 4.3 1000 1.5 65 4.3 1000 0.8 43 4.4 lOOO 0.5 21 4.5 HOO 1.0 30th 3.0 HOO 1.0 40 4.0 1100 1.0 53 4.8 1100 1.0 56 4.0 1100 1.0 65 3.3

Example 2

The starting materials shown in Table 4 are mixed in the same manner as those in Example 1 and pressed.

The pressed body is ^{sintered in air at 1350 °} C. for 1 hour and then cooled to room temperature (about 15 to about 30 ^° C.) in the furnace. The sintered wheel is lapped on opposing surfaces with silicon carbide abrasive into particles which pass through a mesh size of mm. The finished sintered disk is 10 mm in diameter and 1.5 mm in thickness. The opposite surfaces of the sintered disk are provided with a spray-metallized film of aluminum in a known manner. Lead wires are attached to the aluminum electrodes by conductive silver paint. The electrical properties of the finished resistor are given in Table 4. It can be seen that the η value increases noticeably! can be achieved by adding another member from the group consisting of cobalt oxide, manganese oxide, indium oxide. Antimony oxide, tin oxide, barium oxide, nickel oxide and chromium oxide, and the C value at a given current of 1 mA can be markedly lowered by further adding a member of the group of titanium oxide. Boron oxide, aluminum oxide. Molybdenum oxide. Tanta oxide and iron oxide.

Starting materials (mole percent)

further additions

ZnO Bi ₂ O ₃ IO 99.9 0.05 99.4 0.1 15th 99.0
98.5 0.5
1.0 89.5 10.0 90.0 5.0 IO 99.0 0.5 99.0 0.5 98.5 0.5 25th 99.0 0.5 99.0 0.5 99.0 0.5 30th 99.0 0.5 99.47 0.5 99.45 0.5 35 99.3 0.5 97.0 0.5 87.5 0.5 40 99.0 0.5 99.0 0.5 99.0 0.5 45 99.0 0.5 99.0 0.5 99.0 0.5

CoO

CoO

CoO

CoO

CoO

CoO

MnO ₂

In ₂ O ₃

Sb ₂ O ₃

SnO ₂

BaO

NOK

Cr ₂ O ₃

MnO ₂

MnO ₂

MnO ₂

MnO ₂

MnO ₂

TiO ₂

0.05
0.5
0.5
0.5
0.5
5.0
0.5
0.5
1.0
0.5
0.5
0.5
0.5
0.03
0.05
0.2
2.5
12.0
0.5

B ₂ O ₃ 0.5

Al ₂ O ₃ 0.5

MoO ₃ 0.5

Ta ₂ O ₅ 0.5

Fe ₂ O ₃ 0.5

Electrical! "Properties of the finished resistors

(at a

given current

of 1 mA)

34

48 62 73 97 105 84 250 75 214 76 49 178 16 130 90 140 200 8.2 6.5 3.6 11.2 9.8 5.3

Example 3

The starting materials according to Table 5 wenkr pressed, annealed, lapped and with electrodes yj; see in the same way as in example 2. 1> u electrical properties of the resulting cons is shown in Table 5. It is easy to see that. wan the sintered body of tin oxide, the bismuth oxii, still contains at least two other members Group of cobalt oxide, manganese oxide, boron oxide, barium oxide, indium oxide, antimony oxide, titanium oxide. and contains chromium oxide, the resulting sintered body exhibits excellent non-linear properties fr> knows. Among these samples, the titanium oxide shows cn; holding sintered bodies a relatively low (for a given current of I mA and an auseczciclr nete ·; high »1.

3742

Table 5

I 802452

Starting materials
(Mole percent

ZnO! Bi ₂ O ₃

CoO I MnO,

98.95 j

0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5

0.5

0.5

0.5

0.05

1.0

5.0

0.5

0.5

0.5

0.5

0.5

0.5

0.05

0.5

5.0

0.5

0.5

0.5

further additions

0.5
0.5
0.5
0.5
0.5
0.5

0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5

B ₂ O ₃

BaO

In ₂ O ₃

Sb ₂ O ₃

TiO ₂

Cr ₂ O ₃

B ₂ O ₃

BaO

In ₂ O ₃

TiO ₂

Cr ₂ O ₃

B ₂ O ₃

BaO

In ₂ O ₃

Sb ₂ O ₃

TiO ₂

Cr ₂ O ₃

0.5 0.5

0.5]

0.5 I.

0.5

0.5

0.5

0.5

0.5

0.5 0.5 0.5 0.5 0.5 LO 0.5 0.5

63

87 109

82

93 118

88

52 318 160

31 252 101

73 385 150

58 303

78

50 294 110

31.5 22S

I 12.8 j 14.3 '13.8 13.1 15.3 \ 14.5 j 21.3 I 22.3 ii6.2! 25.3

! 9.0

i 19.3 i 22.2 j 21.5

! l7.8

; 20.0

S 25.4 i 26.8 j 21.4! 33.5! 14.0

Table 6

Electrical properties of the

finished resistors

(given a j given 1 _(] current ^!

of 1 mA) j ,

lirwärmungstcniperuHir (C)

pressed
body

800
1000
1150
1300
1400

1350
1350
1350
1350

Puff

800

800

800

800

800

600

800

1000

1200

1300

Electrical properties of the finished resistors

(at a given current of 1 mA)

300

230

170

100

85

13th

90

130

80

24

8.3 7.8 7.5 7.2 4.2 7.3 7.2 5.1 2.6

Example 5

A mixture in a composition according to Table 7 is pressed and calcined to the same Like that in Example 2. The sintered body is lapped on opposite surfaces and covered with the paste from Example 4 on these surfaces. The ones on the opposite surfaces The paste applied is heated to 800 ° C. in air for 30 minutes. Then Al electrodes and lead wires attached to said surfaces in the same manner as in Example 1. the electrical properties of the resistor are shown in Table 7. It can be seen from a comparison between Tables 4 and 7 that the n-value of the resistance can be greatly increased by Use of the bismuth oxide containing paste.

Example 4

A sintered body of pure zinc oxide is prepared by pressing zinc oxide powder at 340 kg cm ³ and heating the pressed body at the temperature shown in Table 6 for 1 hour. After cooling to room temperature, the sintered body is lapped on both opposing surfaces with silicon carbide abrasive. The lapped surfaces are coated with a paste containing 50 percent by weight bismuth oxide in a solution of epoxy resin and butyl alcohol. The opened pastes are calcined in air at a temperature according to labelleö for 30 minutes. A chemical analysis of the annealed body indicates. dal * bismuth oxide diffuses into the sintered body of zinc oxide. Then, the opposite surfaces of the sintered disk are provided with Al electrodes and lead wires in the same manner as in Example 1. The electrical properties of the resulting resistance are shown in Table 6. It can easily be seen from a comparison between labeled and 6. that the n-value of the resistance can be greatly increased by the glowing of the paste containing bismuthovid

99.5 Table 7 lgsmaieriaüen LUekinvoicing properties 130 130 I.
Stroml ίϊ Output i 99.5 o! pro7ent of the finished resistors SnO ₂ 0.5 284 1 M. * ^ * -) S. additions C.
(given a BaO 0.5 105 I.
I. 15.3 / ill) ^: 99.5 j from I mA) NiO 0.5; 80 1
! 19.7 i 99.5 I.
In ₂ O., 0.5 220 TiO ₂ 0.5 15 1 18.5 99.5 Sb ₂ O ₃ 0.5 B ₂ O, 0.5 12 j 20.2 99.5 Al ₂ O, 0.5; 6.3 I. 12.5 99.5 MoO, 0.5 15 9.3 99.5 Ta ₂ O, 0.5 14 \ 8.5 99.5 Fe ₂ O, 0.5 ■ 7.6 i 8.2 gg s Cr ₂ O, 0.5 163 9.8 99.5 Al ₂ O, 0.1; 112 9.2 99.9 Al ₂ O, 0.2 46 8.S 9 «.S Al ₂ O, 1.0 6.2 j 19.5i 99.0 CoO 0.05 51 10.? 99.9> CoO 0.5 S3 5 / 99. s CoO 5.0 1 y 9 \ 0 7 ,; 17 ', 9

'~ li Λ

continuation

Raw materials
Mole percent additions Electrical Properties
of the finished resistors / J ZnO MnO ₂ 0.05 C.
(at a given stream
of 1 mA) 8.4 99.95 MnO ₂ 0.1 96 15.3 99.8 MnO ₂ 2.5 114 6.8 97.5 MnO ₂ 12.0 177 2.6 88.0 450

Example 6

A mixture in a composition shown in Table 8 is made in the same manner as in Example 1 pressed. The pressed body is left in air at the temperature shown in Table 8 for 1 hour sintered and then cooled in the oven to room temperature. The sintered disk becomes a non-ohmic one Resistance completed in the same manner as in Example 5. The electrical properties of the finished resistor is shown in Table 8. It can be seen that the n-value of the resistor can be greatly increased by using the bismuth oxide-containing paste as a comparison between Tables 5 and 8 results.

Table 8

Starting materials (mole percent)

uO

0.5

0.5

0.5

0.05

1.0

5.0

0.5

0.5

0.5

0.5

0.5

0.5

rvi π V

0.05

0.5

5.0

0.5

0.5

0.5

0.5
0.5
0.5
0.5
0.5

0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5

other additions

B ₂ O ₃

BaO

In ₂ O ₃

Sb ₂ O ₃

TiO ₂

Cr ₂ O ₃

B ₂ O ₃

BaO

In ₂ O ₃

Sb ₂ O ₃

TiO ₂

Cr ₂ O ₃

B ₂ O ₃

BaO

In ₂ O ₃

Sb ₂ O ₃

Al ₂ O ₃

0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5

Settling temperatures

(C)

1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 1350 I 1350 1350 1350 1350

Electrical Properties

of the finished resistors

(in the case of a given

Current of 1 mA)

87 104 132 101 125 146

92

81 283 216

66 235 130

94 340 190

66 282

89

60 243 120

22nd

15.4 17.6 18.3 17.9 19.0 18.1 25.6 27.2 19.5 29.4 13.7 22.8 29.5 28.3 22.7 34.5 13.7 25.6 31.5 32.4 25.5 39.2 12.3

Base Maierialien (mole percent)

ZnO 'CoO

MnO,

further additions

Sintering temperatures

(C)

Electric

properties

the finished

Resistances

(given a

Current of 1 mA)

98 * -05 0 5 TiO, 0.5 1350 37 13, U

98 * 5 0 5 0.5 TiO, 0.5 1000 74 14.7

98 5 0.5 0.5 TiO ₂ 0.5 1100 57 Π-

98 5 05 0.5 TiO, 0.5 1200 43

9S ', 5 0.5 0.5 Cr ₂ O ₃ 0.5 1350 223 j 27. Example 7

A mixture having a composition as shown in Table 9 is pressed and calcined in the same manner as in Example 2. The sintered body is lapped on opposite surfaces and then covered with a paste containing solid components according to Table 9. The applied on the opposite surfaces of paste is heated in air 30 mimed heated at 800 ⁰ C. Then, Al electrodes and lead wires are attached to the opposite surfaces in the same manner as in Example 1. The electrical properties si of the finished resistor are shown in Table 9.

Table 9

Raw materials additions Weight percent
the fixed CoO MnO ₂ Electric
Properties of the η (Mole percent) Components manufacture
Resistances MnO ₂ 0.5 30th C. 19.5 B ₂ O ₃ 0.5 30th - (at a 34.2 ZnO BaO 0.5 Bi ₂ O ₃ 30th - given
electricity 43.4 In ₂ O ₃ 0.5 30th - of 1 mA) 27.3 99.5 Sb ₂ O ₃ 0.5 70 30th : 40 42.1 99.5 TiO ₂ 0.5 70 30th 60 16.8 99.5 Cr ₂ O ₃ 0.5 70 30th 72 32.1 99.5 CoO 0.5 70 - 30th 215 24.3 99.5 B ₂ O ₃ 0.5 70 - 30th 130 37.5 99.5 BaO 0.5 70 - 30th 24 43.1 99.5 In ₂ O ₃ 0.5 70 - 30th 158 24.3 99.5 Sb ₂ O ₃ 0.5 70 - 30th 70 40.8 99.5 TiO ₂ 0.5 70 - 30th 64 16.6 99.5 Cr ₂ O ₃ 0.5 70 - 30th 77 34.2 99.5 - 70 - 30th 220 12.7 99.5 - 70 30th - 140 11.3 99.5 - 70 25th 25th 37 13.4 99.5 B ₂ O ₃ 70 25th 25th 167 38.1 100 BaO 70 25th 25th 200 43.3 100 In ₂ O ₃ 70 25th 25th 180 32.2 100 Sb ₂ O ₃ 50 25th 25th 150 45.8 99.5 TiO ₂ 50 25th 25th 58 17.2 99.5 Cr ₂ O ₃ 50 25th 25th 67 35.6 99.5 50 200 99.5 50 110 99.5 50 22nd 99.5 50 148

Example 8

The resistors of Examples 1, 3, 5, 6 and 7 are tested according to the procedures used with electronic components. The endurance test under load is carried out at 70 ° C ambient temperature at 1 watt nominal power for 500 hours.The heat cycle test is carried out by repeating the cycle five times in which the resistors are kept at 85 ° C ambient temperature for 30 minutes, then quickly to -20 ° C cooled and held at this temperature for 30 minutes. Table 10 shows the average changes in the C and η values of the resistors after the heat cycles and the life test.

Table 10

Resistance and the changes after the life-learning test, which in a similar way w, e, m example 8 is shown in Table 12.

Table 1 i

sample

No.

Example 2 Example 3 Example 5 Example 6 Example 7

Changes after
Lifetime test

Changes after

He "'insolent

cycle test

10
8th
7th
4th
4th

-10

-12

-4

-6

-6

-5
-6

-2
-2

Example 9

Bi ₂ O, 3, O, No. (Weight (Weight percent) percent 1 75 13th 2 70 11th 3 70 11th 4th 62 11th

SiO, CoO MnO, Weight (Weight (Weight percent) percent) percent 12th - - U 8th - 11th - 8th 11th 8th 8th

Table 12

A mixture with a composition shown in Table 12 is pressed in the same way as in Example 2. The pressed body is ^{sintered in air at 135O 0} C for 1 hour and then cooled in the oven to room temperature. The sintered disk is lapped on opposite surfaces and coated there with a paste, the composition of which is given below. The paste applied to the opposite surfaces is heated in air at 800 ° C for 30 minutes. The pastes have a solid component composition as shown in Table 11 and are prepared by mixing a total of 10 parts by weight of the solid components with 100 parts by weight of epoxy resin in 20 to 40 parts by weight of butyl alcohol. Then, Al electrodes and lead wires on the given lying surfaces in the same manner as in Example 1 attached. The electrical properties of the finished

additions Upper Electric η Change C. 1 η ZUgS- Properties of the
manufacture struggles
after Raw materials mate- Resistances 4.0 Life 2 -4 (Mole percent I. rials C. 8.0 lasted i 2 -3 No. at a 9.5 (° / 3 -3 given
electricity 11.4 2 -2 ZnO CoO 0.5 1 of 1 mA) 15.3 1 -3 MnO ₂ 0.5 2 200 23.2 2 -3 100 In ₂ O ₃ 0.5 3 210 14.3 2 -3 100 Sb ₂ O ₃ 0.5 4th 250 22.6 1 -4 100 TiO ₂ 0.5 1 180 13.5 1 -2 100 B ₂ O ₃ 0.5 1 60 19.1 2 -2 99.5 Al ₂ O ₃ 0.5 1 103 12.7 1 -3 99.5 SnO ₂ 0.5 1 180 14.5 2 _2 99.5 BaO 0.5 1 90 21.4 2 -3 99.5 NiO 0.5 1 13th 15.8 1 -2 99.5 In ₂ O ₃ 0.5 1 41 29.5 2 _2 99.5 In ₂ O ₃ 0.5 1 18th 31.9 2 -2 99.5 In ₂ O ₃ 0.5 1 150 33.4 1 -1 99.5 Cr ₂ O ₃ 0.5 1 92 18.1 1 -1 99.5 2 57 99.5 3 143 99.5 4th 150 99.5 1 130 99.5 141 99.5

1 sheet of drawings

Claims (10)

Patent claims: 1. Voltage-dependent resistor, characterized in that the resistor 5tand from a sintered body in a composition consisting essentially of 80.0 to 99.9 mole percent zinc oxide, 0.05 to 10.0 mole percent bismuth oxide and 0.05 to a total of 10.0 mol percent of at least one oxide from the> o group: cobalt oxide, manganese oxide, indium oxide, Antimony oxide, titanium oxide, boron oxide, aluminum oxide, tin oxide, barium oxide, nickel oxide, molybdenum oxide, Tanialoxid, iron oxide and chromium oxide, is formed, consists and is opposite Surfaces of this sintered body are attached ohmic electrodes. 2. Voltage-dependent resistor according to claim 1, characterized in that the sintered body has a composition consisting essentially of 94.0 to 99.8 mole percent zinc oxide, 0.1 to 1.0 mole percent bismuth oxide and 0.1 to 5.0 mole percent total of at least one Oxides of the group: cobalt oxide, manganese oxide, indium oxide. Antimony oxide, titanium oxide, boron oxide, Aluminum oxide, tin oxide, barium oxide and nickel oxide, molybdenum oxide, tantalum oxide, iron oxide and chromium oxide. 3. Voltage-dependent resistor according to claim 1, characterized in that the ohms see Electrodes one member of the group: electrolytically plated or strom!> S plated Film of Ag, Cu, Ni, Zn and Sn, vacuum evaporated film of Al, Zn, Sn and In and metallized film of Cu, Zn, Sn and Al. 4. Voltage-dependent resistor according to claim 1, characterized in that the sintered body from a composition of essentially 85.0 to 99.85 mole percent zinc oxide, 0.05 to 5.0 mole percent bismuth oxide, 0.05 to 5.0 mole percent cobalt oxide, and 0.05 total up to 10.0 mol percent of at least one oxide from the group: manganese oxide, boron oxide, barium oxide, indium oxide, Antimony oxide, titanium oxide and chromium oxide. 5. Voltage-dependent resistor according to claim 1, characterized in that the sintered body from a composition of essentially 85.0 to 99.85 mole percent zinc oxide, 0.05 to 5.0 mole percent bismuth oxide, 0.05 to 5.0 mole percent manganese oxide, and 0.05 total up to 5.0 mol percent of at least one oxide from the group: cobalt oxide, boron oxide, barium oxide, indium oxide, Antimony oxide. Titanium oxide and chromium oxide. 6. Voltage-dependent resistor according to claim 1, characterized in that the sintered body from a composition of substantially 84.00 to 99.80 mol percent zinc oxide, 0.05 to 5.00 mol percent bismuth oxide, 0.05 to 3.00 mol percent cobalt oxide, 0.05 to 3.00 mol percent manganese oxide and a total of 0.05 to 5.00 mol percent of at least one oxide from the group: boron oxide. Barium oxide, indium oxide, anti- ^fl 5 monoxide. Titanium oxide and chromium oxide. 7. A method for producing a voltage-dependent resistor which consists of a sintered body made of zinc oxide, in which 0.1 to 1.0 mol percent bismuth oxide contain and are attached to the ohmic electrodes on opposite surfaces of the sintered body, characterized in that a sintered body is made Zinc oxide pretends to coat the opposite surfaces of the sintered body with a paste that contains bismuth oxide in finely divided powder form as a solid component, ^{heats the coated body at a temperature of 600 to 1200 0} C in an oxidizing atmosphere so that bismuth ions diffuse into the mass of the sintered body, and cools the body diffused with bismuth to room temperature. 8. A method for producing a voltage-dependent resistor according to claim 7, characterized in that characterized in that a sintered body of zinc oxide and a total of 0.1 to 5.0 mol percent at least one oxide from the group: cobalt oxide, manganese oxide, indium oxide. Antimony oxide, titanium oxide, Boron oxide, aluminum oxide, tin oxide, barium oxide, nickel oxide, molybdenum oxide, tantalum oxide, Iron oxide and chromium oxide, is used. 9. A method for producing a voltage-dependent resistor according to claim 7, characterized in that characterized in that a paste is used which as a solid constituent 20 to 80 percent by weight Contains bismuth oxide in finely divided powder form and the remainder of at least one Compound of the group of cobalt compounds and manganese compounds. 10. A method for producing a voltage-dependent resistor according to claim 7, characterized in that It is noted that a paste is used which contains pulverized glass frit as a solid component in a composition containing essentially 48 to 80 percent by weight bismuth oxide, 8 to 23 percent by weight boron oxide, 8 to 23 percent by weight silicon dioxide, and the total 4 to 16 percent by weight of at least one oxide from the group: cobalt oxide and manganese oxide, contains.