JPS623963B2 - - Google Patents

Description

[Detailed description of the invention]

In the present invention, in a sintered body whose main component is zinc oxide, a part of the zinc oxide component is replaced with metal zinc as a starting material, and at least vanadium and tetravalent atomic elements are added as additives such as silicon, titanium, and zircon. , relates to a method of manufacturing a voltage nonlinear resistance element containing at least one of tin. In recent years, with the rapid development of semiconductor devices and circuits such as ICs, transistors, and thyristors, and their applications, the use of semiconductor devices and circuits in measurement, control communication equipment, and power equipment has become widespread, and these devices have become smaller and have higher performance. As technology advances, the use of micromotors is rapidly increasing. However, with such progress, the withstand voltage, surge, and noise resistance of these devices and their components are not sufficient to withstand the spark voltage generated by the commutator of a micromotor. For this reason, protecting these devices and components from abnormal surges and noise, or stabilizing circuit voltages, has become an extremely important issue. To solve these problems, there is a need to develop a voltage nonlinear resistance element that has high nonlinearity at low varistor voltage and has fast response. Conventionally, voltage nonlinear resistance elements such as SiC varistors and Si varistors have been used for these purposes. The current-voltage characteristics of a varistor are generally expressed by the following relationship: I=(V/C). Here, V is the voltage applied to the varistor and I is the current flowing through the varistor. Further, C is a constant corresponding to the voltage when a given current is passed. A nonlinear coefficient α=1 is a normal resistor that follows Ohm's law, and it can be said that the larger α is, the better the nonlinearity is. Here, instead of expressing the varistor characteristics as C and α, 1mA
Let it be expressed by the rising voltage V1mA and α. Further, the response speed to a spike voltage such as a spark voltage that has a fast rising voltage and a short wavelength is determined by the capacitance of the varistor itself, and the larger the capacitance, the faster the response speed. traditionally used
For example, SiC varistors are not satisfied with α=3 to 4 in a low voltage region of about V1mA=10 to 20V, and SiC varistors need to be fired in a non-oxidizing atmosphere. On the other hand, Si varistor is Si P-
Forward rising voltage of N junction (approx.
0.6V), and has the disadvantage of high cost because it requires stacking multiple silicon chips to obtain the required varistor voltage. Furthermore, a recently developed low-voltage zinc oxide-bismuth oxide varistor has a high nonlinear coefficient α of about 20, but the response speed is slow and the spark voltage cannot be controlled. The present invention aims to solve the above-mentioned drawbacks, and in a sintered body mainly composed of zinc oxide, a part of the zinc oxide component as a starting material is replaced with metal zinc, and at least vanadium and tetravalent zinc are added as additives. Because it contains at least one of atomically valent elements such as ions, titanium, zircon, and tin, it has a high nonlinear coefficient and a very large capacitance, so it has high-speed response and has low nonlinearity. Because it is caused by the sintered body itself, it exhibits symmetrical voltage-current characteristics, and by changing the thickness of the sintered body, it is possible to obtain any desired varistor voltage value, and it is extremely easy to manufacture because it can be fired in air. The present invention aims to provide a simple method for manufacturing a voltage nonlinear resistance element. The details of the present invention will be explained below based on one embodiment. Example Silicon oxide, titanium oxide, zirconium oxide, which are metal oxides with tetravalent valence, are prepared by adding metallic zinc in the range of 0.01 to 20 mol% and vanadium oxide in the range of 0.001 to 1 mol% to zinc oxide. 0.01 to 10 mol % of at least one of tin oxide was added, and the mixture was thoroughly mixed and formed into a disk shape with dimensions of 15 mmφ x 1 mmt, and fired at a high temperature of 1000° C. or higher in air. When electrodes were attached to both sides of the fired sintered body and its characteristics were measured, the results shown in Table 1 were obtained.

[Table] In other words, Table 1 investigates the characteristics when the thickness of the sintered body is fixed and the type of electrode is changed. It can be seen that the sintered body itself is a nonlinear element whose characteristics change depending on the thickness of the sintered body.
Next, FIG. 1 shows the change in α value corresponding to V1mA when the amount of metal zinc added is changed while keeping vanadium oxide = 0.05 mol % and silicon oxide = 2 mol % constant. Furthermore, FIG. 2 shows the change in α value corresponding to V1mA when the amount of vanadium oxide added is changed while keeping metal zinc = 3 mol % and tin oxide = 2 mol % constant. It can be seen from FIG. 1 that a high nonlinear coefficient α of 8 to 12 can be obtained when metallic zinc is 0.01 to 20 mol % and vanadium oxide is 0.001 to 1 mol %.
If the amount of metallic zinc added is less than 0.01 mol% or more than 20 mol%, not only the nonlinear coefficient α becomes low but also the stability deteriorates. When the amount of vanadium oxide added is less than 0.001 mol% or more than 1 mol%, the nonlinear coefficient α becomes low. Table 2 shows the V1mA values and nonlinear coefficients of sintered bodies with different composition ratios.

[Table] From this Table 2, by appropriately selecting the additive and its addition amount, V1mA can be lowered and the nonlinear coefficient α=
It can be seen that high values of 8 to 12 are obtained. Figure 3 shows the α value corresponding to V1mA when the amounts of silicon oxide, titanium oxide, zirconium oxide, and tin oxide are varied while keeping zinc metal = 3 mol% and vanadium oxide = 0.05 mol% constant. Show change.
In FIG. 3, curve A is silicon oxide, curve B is titanium oxide, curve C is zircon oxide, and curve D is changes when the amount of tin oxide added is changed. It can be seen from FIG. 3 that a high nonlinear coefficient α of 8 to 12 can be obtained when the amounts of silicon oxide, titanium oxide, zircon oxide, and tin oxide are each 0.01 to 10 mol %. These addition amounts are less than 0.01 mol% or 10
In a range exceeding mol %, the nonlinear coefficient α becomes low. FIG. 4 shows a zinc oxide-metallic zinc-vanadium oxide varistor (ZnO 94.95 mol%-Zn 3 mol% _{-V2O5 0.05} mol%-SiO2 _0.5 mol% _-TiO2 ) according to an example of the present invention (curve 1). 0.5 mol% - _ZrO2 0.5
mol% - SnO ₂ 0.5 mol%) and zinc oxide-bismuth oxide varistor (ZnO 96.5 mol% - _{Bi 2} O ₃ 0.5 mol% - Co ₂ O ₃ 1) according to the conventional reference example (curve 2)
mol% - MnO ₂ 1 mol% - NiO 1 mol%)
A comparison of capacitance characteristics corresponding to V1mA is shown.
From Figure 3, the example (curve 1) is the reference example (curve 2).
It can be seen that the capacitance is larger and the high-speed response is excellent. In the above explanation, vanadium, silicon, titanium, zircon, and tin are exemplified in the form of vanadium oxide, silicon oxide, titanium oxide, zirconium oxide, and tin oxide, but it is sufficient that they become oxides after firing. Needless to say, there is no limit. In addition to vanadium and at least one of silicon, titanium, zircon, and tin, additives include vanadium, silicon, titanium, zircon, bismuth other than tin, cobalt, manganese, iron, nickel, copper, chromium, aluminum, and magnesium. , one or more metal oxides or fluorides such as antimony, tantalum, hafnium, and lead may be added. As described in detail above, according to the present invention, a part of the zinc oxide component is used as a starting material in a method for manufacturing a voltage nonlinear resistance element whose main component is zinc oxide and whose sintered body itself has voltage nonlinearity. Ni substituted with zinc, containing at least vanadium as an additive, and having a tetravalent valence as another additive,
Provided is a method for manufacturing a voltage nonlinear resistance element that contains at least one of titanium, zircon, and tin, has a high nonlinear coefficient, has good high-speed response, is extremely simple to manufacture, and has stable characteristics. can do.

[Brief explanation of the drawing]

Figure 1 shows V1 when the amount of metallic zinc added is changed.
A curve diagram showing the change in α value corresponding to mA, Figure 2 shows V1m when the amount of vanadium oxide added is changed.
A curve diagram showing the change in α value corresponding to A. Figure 3 shows V1mA when the amounts of each of silicon oxide, titanium oxide, zirconium oxide, and tin oxide are changed.
FIG. 4 is a curve diagram showing a change in the α axis corresponding to the curve, and FIG. 4 is a curve diagram showing a comparison of the capacitance characteristics corresponding to V1mA between the embodiment of the present invention and the conventional reference example.

Claims (1)

[Claims] 1. In a method for manufacturing a voltage nonlinear resistance element whose main component is zinc oxide and whose sintered body itself has voltage nonlinearity, 0.01 to 10% of the zinc oxide component is used as a starting material.
20 mol% is substituted with metal zinc, and contains at least 0.001 to 1 mol% of vanadium converted to V ₂ O ₅ as an additive, and also has a tetravalent valence as other additives, such as nitrogen, titanium, zircon, At least one type of tin is converted into SiO ₂ , TiO ₂ , ZrO ₂ , and SnO ₂
A method for manufacturing a voltage nonlinear resistance element, characterized in that it contains 0.01 to 10 mol%.