JPS59205706A - Varistor and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a low-voltage varistor containing zinc oxide as a main component and a method for manufacturing the same.

Traditionally, the main ingredient is zinc oxide. 8 i $103.

MgO,0r203. Fe2O2, Sby, Us, O
oO, MnO.

Group 1i with two voltage-sensitive oxides such as NiO and a conductive oxide! Zinc oxide varistors formed by molding and sintering are widely used because of their excellent nonlinearity. These zinc oxide-based varistors have a rising voltage of V l mA 7 m in the sintered body layer lx, and various rising voltages are manufactured, but this rising voltage is due to the fact that the main component is zinc oxide in the sintered body. It is determined by the size of the crystal grains. That is, in order to obtain a low rising voltage, it is necessary to grow large crystal grains, and in order to obtain a rise voltage that is 1c higher, it is necessary to suppress the growth of crystal grains and to construct the crystal grains from small crystal grains. BI20s, MlzO, 0rzU5. Fe2U3゜5
In a lead oxide-based varistor made by adding b203, OoO, MnO, Nio, etc., the crystal grain size is about 15 μm, and the rise voltage can be determined by about 80 to 300 V based on the composition. From the above composition, except for 5bzO:+, the crystal grain size is about 50 μm, and the rising voltage is 20 to 40 V.
It is also known that the degree of In recent years, there has been a particularly strong demand for lower voltages for zinc oxide based varistors, and it has become an important issue to obtain zinc oxide based varistors containing large aluminum crystal grains. As a means of obtaining such large crystal grains, for example, there is a technique proposed in Japanese Patent Publication No. 11203/1983. This is 99.9-99.5 mol% of lead oxide and BaO or S r 0 0.1-(), 5 mol%
After mixing, calcination and hydrothermal decomposition are performed to obtain crystal grains of about 70 μm, and the crystal grains are mixed with powder containing zinc oxide as the main component [0.1 to 60% by weight and mixed, and then sintered. It is what it is. However, in order to obtain crystal grains by hydrothermal decomposition, the zinc oxide must be BaO, S, rO
It has to be prepared, added with a binder, molded, calcined at a high temperature of 1300°C, pulverized, and then hydrothermolyzed, resulting in a large number of steps. Large crystal grains cannot be obtained unless the calcination temperature after molding is high; for example, in order to obtain crystal grains with a weight of 70μ,
'(!) It requires a high calcination temperature, and there are technical and cost problems such as temperature control and selection of materials for the sintering furnace. If the calcination temperature to obtain these crystal grains is high, the growth of the crystal grains themselves will progress, resulting in a decrease in activity. Since the sintering temperature when obtaining the sintered body and the above-mentioned calcination temperature are close to each other, the growth of crystal grains is close to the limit, and therefore, the crystal grains grow almost all in the sintering process when obtaining the sintered body. The disadvantage is that even after welding, only 1.7" L of crystal grains, which is the same size as the crystal grains obtained by hydrothermal decomposition, is obtained.

The present invention has been made in view of the above points, and consists of particles obtained by granulating zinc oxide and lead titanate, and containing zinc oxide as an IE component and at least bismuth oxide added thereto. Addition 117. By combining and sintering the particles, the particles are dispersed and located inside the sintered body, and the FM of the crystal grains with this 7"L as the nucleus is aimed at. The entire purpose of this invention is to reduce the rtt pressure of the varistor by arranging crystal grains.The details of the present invention will be explained below with reference to examples.

Example: 90% titanium lead powder and 90% titanium lead powder,
003% k %, 0.01 mole, %, 0.
03 mol%.

0.1 mole%, C), 3 mole%, 1.0 mole%, 3. 7 types of zinc oxide + mixed with O mo#chi
A mixed powder of titanium and lead is obtained, and a binder and water are added and mixed. When this is placed in a spray dryer and granulated, spherical particles in which the water added to the mixed powder has evaporated can be obtained. These spherical particles have a particle size of approximately 3 to 200 μm.
The particles with a size of 60 to 1204 m are the most common (particles with a size of about 20 μm are very rare. The 7 types of particles from the zinc oxide + titanium carrier were sorted by fraud, and the oxidized particles with an average particle size of 100 μm were found. Particles of zincate titanium lead were obtained and mixed with 94.5 mol% zinc oxide + 3 mol% Mg.
10Hrhos 0.5 mol% +Oo01.0 mol qb +MnOO,% to 5 mo +-Ni00.5 mol% to e, 0.1 folds each for 6 main compositions, 0
．． Triple beak.

Zinc oxide Figure 1 shows the relationship between the point of addition of lead titanate and Figure 2 shows the nonlinear coefficient α. In both curves, when the amount of zinc oxide + lead titanate particles added to the main composition is 0.1% by weight,
Similarly curve + 8 + 0.3 electric current, curve La 10 - weight%, curve) #i30 iron II%, white belt (yuzu F'i60
This is a case of weight %.

Furthermore, Fig. 3 is a curve diagram showing the relationship between the zero loading and the rising voltage of this particle with respect to the main composition, using zinc oxide titanium axillary particles with an average particle size of 100 μm, and Fig. 4 is a curve diagram of this particle. These are curve diagrams showing the relationship between the amount of addition and the non-linear coefficient.
The amount added is 0.003 mol.
01 molar ratio, curve 0 is 0.1 molar ratio, curve tD is 1.0
This shows the case where the curve tJ+ is 3.0 moles. In addition, @5 Figure V'cVi 0.1 mol% of lead titanate was added to the zinc oxide. N (-Titanium is lead) The figure below shows the curve showing the relationship between the particle size and the rising voltage.
r'p,' Figure 6 is a curve diagram showing the relationship between the particle size and the nonlinear coefficient. The amount of 0.01 molar or more is good except for curve diagrams, but
The nonlinear coefficients in Figure 2 are curves (lead titanate except for υ).
The results show that the addition amount is good up to 1.0 mol, and when it exceeds this, it drops rapidly. From the results shown in Figures 1 and 2, lead titanate (D t tj: o, ol ~ 1.0 molar ratio is good when added to zinc oxide), and this oxide [lead lead titanate]
When adding particles to the main composition, a weight ratio of 0.3 to 30 is good. Also, in Figures 3 and 4, the influence of the amount of lead titanate in the sacrificial lead oxide + titanium plate particles on the characteristics is shown by the curve (8 is the rising edge of Figure 3).
In addition, the curve in Figure 4 (Jl) shows that the nonlinear coefficient is inferior.In Figure 3, the amount of zinc oxide and titanium wave particles added to the main composition is 0. ．It shows a remarkable effect from 3-fold It-chi, and Fig. 4 shows that it is good up to 30-It, but deteriorates rapidly beyond this.Therefore, compared to the main composition, zinc liquefied + titanium-lead particles are good. Therefore, the amount of lead titanate added to zinc oxide is set in the range of 0.01 to 1.0 mol. Therefore, this range is exactly the same as in Figures 1 and 2. It shows.

Furthermore, the relationship between the particle diameter of zinc oxide lead detatitanate, the rise voltage, and the non-+N and lfN coefficients is shown in Figures 11 and 6. The sample was added to zinc oxide.7. Lead Quantity: 0.1 mol For the main composition which is the same as the example, zinc oxide and titanium mol.
It is recommended to use particles that have been added and mixed in an OK amount. In FIGS. 5 and 6, the same amounts of zinc oxide and lead titanate powder as in the example were directly added to the conventional raw silk FjW, and these were mixed and heated at a temperature of 1100 to 1400°C. This shows the case of simultaneous sintering, and the granulation process of lead oxide and titanium lead is omitted.

According to this, 7 is granulated with a spray dryer and zinc oxide +
When the average particle size of lead titanate particles is 10 μm, the nonlinear coefficient changes from the conventional one fz<, and the rising voltage V l m
It is clear that A 7m is lowered from the conventional 39V to 29V and a very low voltage varistor can be obtained, and the rise voltage shows a sharp drop as the average particle size becomes smaller. However, the nonlinear coefficient is 30 compared to the average particle size of 100.
When it exceeds μm, it decreases rapidly and becomes damp, and at 200 μm &''
i22 and this value is a usable value, but 30
At 0 μm, it further decreases to 1o, which is 16, which does not attack when used.

From the above, it can be determined that the appropriate particle size for granulating zinc oxide + lead titanate is 10 to 200 μm.

Based on this result, 0.01 to 1.0 mol of lead titanate was added to the lead powder V to granulate it, and the average particle size was 10.
~200μm oxide curve, lead 10 titanium door lead particle gold, and zinc oxide 10% 1gU+-Bri203+Co (JlMn
0.3 to 30 oil i for the main composition from O+NiU
By adding f% to form mixed particles and sintering them together, low weight particles with excellent characteristics such as rise voltage and nonlinear coefficient are produced.
A pressure varistor can be obtained.

Example 2 In the above example, the main composition was zinc oxide + MgO + Bi.
Although we have described the case where a material consisting of zOs+-0oU+MnO+Ni is used, in this Example 2,
A case will be described in which L VCS ba 03 and 0r2031 are added as the main composition. 5bzOt and 0rzQ
It has the property of inhibiting the grain growth of zinc oxide because it quickly diffuses into low-staining point metals such as sulfur oxide Itti, bismuth, which promotes the grain growth of lead, and their oxides. Therefore, varistors whose main component is zinc oxide such as 5b203 or CrgU3 (() cannot expect crystal grain growth of zinc oxide and the crystals become small, so they are used for relatively high-voltage applications and are not suitable for low-voltage applications. First, 0.003 mol% of lead titanate powder was added to the lead oxide powder,
0.01 mole - 0.03 mole% l001 mole ratio, 0.3
A molar ratio of 3.0 mol was added and mixed and granulated using a spray dryer to obtain '7 types of zinc oxide and titanium oxide particles. Spherical particles of lead acid were obtained. These particles contain 94 mol% of zinc oxide + M g 03 mol - 10 Bi
253 o, 5 mol qb+Oo01. or=le%+M
n.

0.5 mol + Ni00.5 mol + Sbs + 030-
For the main composition consisting of 3 molar ratio + 0r20s O-2 molar ratio, 0.1% by weight, 0.3 weight ratio, 10 double molar ratio,
30% by weight and 600% by weight were added and mixed, molded, and molded into 1100~l at a temperature of 400'C.
The rise voltage when sintered for ~8 hours is shown in Figure 7 in relation to the number of lead titanate added to zinc oxide, and the nonlinear coefficient is shown in Figure 8. Both are curves (Rei is oxidation 11 relative to the main composition, lead deca titanate, lead. When the amount of particles added is 0.1% by weight, the curve is 0.3 weight qb, the curve i + M is 10 weight h1, the curve ( N is a 300% by weight curve (in the case of Oke 60 weight percent). Figure 9 also shows the amount of addition of zinc oxide lead detatitanate particles with an average particle size of 100 μm and the rise voltage with respect to the main composition. Figure 1O shows a curve diagram showing the relationship between the amount of particles added and the nonlinear coefficient.

Note that inside the curve +I, the amount of lead titanate added to the salivary lead of lead + titanate particles is 0.
003 molar relationship, curve Q is 0.01 molar, curve ij is 0.1 molar, curve (81 μm, 0 molar relationship, curve tIM-j3.o molar is shown). Figure 311 shows the oxidizable lead + titanium spheroid when oxidizing lead decatitanium lead particles with 0.1 mole of lead titanate added to hm-zinc are added to the main ffl composition.
FIG. 12 is a curve diagram showing the relationship between particle size and rising voltage, and FIG. 12 is a curve diagram showing the relationship between particle size and nonlinear coefficient. In addition, each sintering is 1100 ~
It was carried out for 1-8 hours at a temperature of 1400'C.

As is clear from these results, the rise voltage and nonlinear coefficient shown in FIGS.
Second drawing! 7.It is not noticeable that the curve ■Excluding workpiece 10, the amount of lead titanate added to zinc oxide is 0.01 to 1.
A range of 0 mol is good.

Therefore, from the results shown in @Figure 7 and Figure 8, the amount of lead titanate added to the lead titanate 011HO, O2N is 2.0 mol, and the amount of zinc oxide decatitanium titanate particles added to the main composition is 0.3 A range of 3 to 3 degrees is good.

It can also be confirmed from FIG. 9 and @1o that this range shows good results in terms of characteristics. As in Example 1, the relationship between the size of the zinc oxide lead detatitanate particles, the rising voltage, and the nonlinear coefficient is shown in FIG. 311 and FIG. 12. The sample has a titanium version added to zinc oxide with a volume of 0.1
Zinc oxide + lead titanate for main composition based on molar ratio
A material to which 1O*W#,% of particles were added was used. In the figure, "conventional" indicates the case where zinc oxide and lead titanate powder of the same strength as in the embodiment are directly added and mixed to the main composition and sintered. As a result, both the rise 'rI/L pressure and the nonlinear coefficient have large absolute values, but they show the same tendency of characteristics as in Example 1, indicating that the average particle diameter of the 1E lead oxide + titanium dolphate particles is 10 to 200 μm. Q can be used.

In this Example 2, the zinc oxide powder is 0. O1~1.0
Mol's titanium B ship was added and granulated to obtain salivary lead oxide + titanium enemy ship particles with an average particle size of 10 to 20,071 m.
This is zinc oxide + MgO + Bit (J3 + CoO + MnO + NiO + 8bzOs
+0.3 to 30 weight tons for the main composition consisting of Cr5lO3
% addition and mixing and sintering them together, a varistor with excellent rise voltage and nonlinear coefficient characteristics can be obtained. Therefore, even if zinc oxide + ChigaaFF particles are added to the main composition containing sbgos and 0rxOsf, which inhibit crystal grain growth of zinc oxide, crystal grains F
i growth, which has the effect of lowering the voltage.

As mentioned above, if the present invention is applied, zinc oxide +
After granulating lead titanate powder, it is added to the main composition of zinc oxide, mixed, molded, and sintered to obtain a varistor.This varistor has a large crystal grain size, so it reduces the nonlinear coefficient. It has the characteristic of reducing the rise voltage without any problems, and is suitable for low voltage applications. In addition, in "Working Example 2", the mixing ratio of lead titanate powder to zinc oxide powder (101 to 1.0 molar ratio, zinc oxide titanium oxide particles added to the main composition) was 0. .3～
Although it has been stated that a range of 30% by weight is good, the amount of titanium iron contained in the sintered varistor is 1tPbTios.
O type K conversion 34 L Teo, oooo3~0.3% ruti. In the examples, main compositions include zinc oxide, bis-qs oxide Vc, Mgo, Coo, MnO, and NiU.

Although the case where 5b20s and Orgys are added has been described, other metal oxides such as 5i02. OuO
.

A 120 a + Ha O+ Ca Or Sr
O+Pb'-), sn02.

Ag2O, TiO2, Zr0z, LazO3, PreU
ll.

FegOa, 8203, etc. may be added, and the material is not limited to this, as long as it forms an oxide GC,7 in air at high temperature. However, the present invention is made of a sintered body consisting of zinc oxide and bismuth oxide as the main components and oxidized "(1 round lead + titanium plate ship particles), which can achieve the effect of lowering the voltage of the varistor. By the way, the MgO,
Although gold PA oxide such as OoO has the effect of improving the characteristics as a varistor, it is not an essential requirement from the viewpoint of lowering the voltage which is the gist of the present invention.

[Brief explanation of drawings]

The drawings are all curve diagrams showing the characteristics of the present invention, reference examples, and conventional examples. Figure 1 shows the relationship between the amount of titanium added to zinc oxide and the rise voltage, and the g2 diagram also shows the relationship between lead titanate and lead titanate.
The relationship between the amount of addition and the nonlinear coefficient, Figure 3 shows the raw silk 5!
Figure 4 shows the relationship between the amount of zinc oxide + lead titanate particles added and the rise voltage, and Figure 5 shows the relationship between the amount of zinc oxide + titanium (2) lead particles added and the non-It line coefficient. Figure 6 shows the relationship between the average grain size of the titanium version particles and the rising voltage, and Figure 6 shows the relationship between the average grain size of the sacrificial lead oxide + titanium iron lead particles and the nonlinear coefficient, and Figures 7 to 12 show the relationship between the average grain size and the nonlinear coefficient. Fig. 7 is a curve diagram showing the characteristics according to an example of
Figure 8 shows the relationship between the addition amount of titanium enemy ship and the nonlinear coefficient, and Figure 9 shows the relationship between the addition amount and rise voltage of the zinc oxide and titanium enemy ship with respect to the main composition. Figure 10 shows the relationship between the amount of lead oxide + titanium diluted lead particles added and the non-111 linear coefficient, and Figure 11 shows the relationship between the average particle size of curved lead oxide and titanium particles and the vertical II: FIG. 12 is a curve diagram showing the entire relationship between the average particle diameter and the nonlinear coefficient of the lead oxide + titanium particles. Patent applicant Marukon Electronics Co., Ltd. Figure 1 t Pbr+oa Zvni= (e+c4) [)
b-cho103 wo extra-θ0 (shi1shi%)
pbT+c) 3 Tracing amount ((decoy)) Fig. 5 KTl, 0 ” PbTiO3f uniformity level B sacrifice (μ) 7
T10 10PbTl03"f"1γki'+2-'iE
(%-) Fig. 7 00, Otton 3θDIDθ35ρノ0-'3LD3.0
pbTi03'ηSa9 mouth % (q3)shiu6
) PbTi 03'; p vD amount ('E
IL2-) Figure 9 0 0. I θ3 r, 0 3. o
ID 30bO
4n mouth amount - (φ逼-7-) Fig. 10 Ago + PbT10s Knot C! %ツ、）Figure 11

Claims (1)

[Scope of Claims] A sintered varistor formed by molding and sintering a sintered body in which lead is mainly composed of oxidized lead gold and several metal oxides including at least bismuth oxide and titanium WF. The amount of lead acid added is PbTi0
Convert to the form of 0.00003 ~. , a barista characterized by being 3 molti. A process of mixing 1E 121 oxide lead powder and titanium enemy ship powder and then granulating it to obtain oxidizing capacity lead + titanium silica particles, a process of sorting the particles to an average particle size, and a process of sorting the particles in this process. A step of adding and mixing the main composition containing at least zinc oxide and bismuth oxide to obtain mixed particles, and a step of shaping and sintering the mixed particles after the step 1.
A method for manufacturing a barista characterized by. (31. A method for manufacturing a varistor according to claim (2), characterized in that the graining is carried out using a spray dryer. (4) The amount of lead titanate added to zinc oxide is 0. A method for manufacturing a varistor according to claim 21 or claim 131, characterized in that the average particle size of the particles is 10 to 200 μm. Claims @ (method for manufacturing a varistor according to any one of Items 21 to 41. The method for manufacturing a varistor according to any one of claims 121 to 51, characterized in that the amount added is 0.3 to 30 weight ts.