JPS5850726A - Composite function element - 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 is characterized in that a sintered body obtained by incorporating a small amount of silicon oxide (S 102 ) into strontium titanate-based conductive porcelain has voltage nonlinearity and has an extremely large dielectric strength. The present invention relates to a multi-function element Sourin I Kushikikai Kyofusuma which has a high efficiency.

Conventionally, Si has been used as a ceramic material with voltage nonlinear resistance.
The burr properties of C varistors and zinc oxide as a main component are approximately expressed as I = (V/C). Here, C is a constant specific to the varistor, and α is a voltage nonlinear index. be.

The SiC varistor utilizes a contact barrier between SiC particles, and α is about 2 to 7. In addition, zinc oxide varistors contain Bi2O3゜0009M in zinc oxide (ZnO).
This is an element obtained by adding a small amount of nO2, 5b2o3, etc. and firing it, and its voltage nonlinearity index α is as high as 60. Since such elements have excellent performance in absorbing high voltages, they are used for voltage stabilization of electronic devices and protection from abnormal high voltages (surges).

However, such conventional varistors have a small dielectric constant and a large dielectric loss angle (tan δ) of 6 to 10 inches, so they are mainly used only for varistor applications.

On the other hand, conventionally, elements obtained by insulating semiconductor porcelain grain boundaries by re-oxidizing or valence compensation, such as grain boundary layer type semiconductor porcelain condensing elements, which have a large dielectric constant (to be more precise, apparent dielectric force), The apparent dielectric constant of this element reaches 50,000 to 60,000. Also, if the composition and conditions are selected appropriately, the tan δ can be around 1 inch, and it can be used as a small capacitor. However, when a current of 1 mA or more passes through the element, it is destroyed and loses its function as a capacitor.

The device of the present invention is an epoch-making multifunctional device that simultaneously has the functions of the two devices described above. That is, it is an element having a complex function of passing high voltage current as a varistor at high voltage and passing abnormal frequency band current as a capacitor at low voltage.

Nowadays, electrical and electronic equipment has come to require extremely sophisticated control, and not only industrial equipment but also consumer equipment has come to require extremely high precision due to the application of microcomputers. Since the logic circuits that make up computers, etc. operate using pulse signals, they have the disadvantage of being easily affected by noise.For this reason, electronic computers, banking machines, traffic control equipment, etc. may malfunction or malfunction due to noise or surges.
When damage occurs, it becomes a social problem. Noise filters have conventionally been used as a measure against such problems.

Noise is an interfering voltage other than the intended signal voltage when operating electronic equipment, and can be divided into those generated artificially and those generated by natural phenomena. Such noise was removed using a circuit that combined a coil and a capacitor. However, the fundamental frequency of artificially generated noise, especially from circuit breakers on power transmission lines, and natural noise, especially from lightning surges, is low, around 5 to 20kHz, and conventional coils and capacitors cannot be used. It was not possible to remove these noises by just combining them. In view of these problems, noise filters that use a voltage nonlinear resistor (varistor) between lines or between lines and ground have recently been frequently used. Since such a noise filter can remove a very wide range of noise, it is effective in preventing malfunctions of microcomputer-controlled equipment. However, such a noise filter has disadvantages in that it requires a large number of parts inside the filter, increases cost, and goes against the trend toward miniaturization.

The device of the present invention has made it possible to solve these problems. That is, since the element of the present invention has a combined function of a varistor and a capacitor, a single element can serve the purpose in a circuit in which conventional elements are connected in parallel.

The device of the present invention is obtained by incorporating a very small amount of silicon oxide (Si'O) into strontium titanate-based semiconductor porcelain.
Figure 1 shows a cross-sectional view of the multifunctional device of the present invention, in which 1 is a sintered body of strontium titanate semiconducting porcelain, 2 and 3
is an electrode.

6 l-“ <Example> 50.22 to 47.95 moles of strontium carbonate.

49.7 to 48.71 mol of titanium oxide, 0.01 to 1.0 mol of silicon oxide, and 0.0 mol of at least one of niobium oxide, tantalum oxide, and neodymium oxide.
After thoroughly mixing the composition containing 6-O,S mulch, it was calcined for 1-6 hours in the range of 1100-125C1, pulverized, an organic binder was added, granulated, and molded.

This molded body was fired in a reducing atmosphere at a temperature of 13oO to 1450°C for 1 to 5 hours to achieve a specific resistance of 0.2 to 0.5Ω.
A sintered body having an average particle size of 20 to 60 μm was prepared.

The shape of this sintered body is 7.5φ×0.7t (size).

Thereafter, heat treatment was performed in air at a temperature of 100° C. to 130° C. for 6 hours to obtain a sintered body 1 shown in FIG. moreover,
Electrodes 2 and 3 were formed on both halves of this sintered body 1. The electrode diameter was 6.0φ (m).

The characteristics of the device thus obtained are shown in the table below.

In the table below, NTi/NSr is the composition amount of titanium oxide and strontium arsenate converted into the atomic ratio of titanium and strontium. ε is the dielectric constant at 1 kHz and is the tan δ number. Surge withstand capacity is a value that indicates how much large current such as lightning surge can be absorbed by the element, and the greater the surge withstand capacity, the better the varistor is. The test is based on a current waveform of 8 x 20 pulses.
μSeC, and the current peak value at which the varistor voltage 1 mA deteriorates by 0.10% with respect to the initial value was defined as the surge withstand capacity.

The number of pulse applications is two.

(Left below) 10.- As is clear from the table above, when the NTi/'' and Sr ratios are 0.
It has the function of a varistor and a capacitor in the range of 90 to 1.26, but especially 0.97 to 1.036 (D range,
) Good surroundings. Further, when the amount of silicon oxide added is in the range of 0.01 to 1.0 molty, the sintered body has polycrystalline grains with uniform grain growth, so the surge resistance is large. If the amount of silicon oxide added is less than 0.01 mole, α is 6
The surge resistance was also 56A. In addition, if the amount of silicon oxide added exceeds 1.0 molt, the sintered body will have polycrystalline grains with grain growth, which will cause the sintered body to easily bend, cause large variations in properties, and cause surges. The withstand capacity is still small at 46A.

Niobium oxide, tantalum oxide, and neodymium oxide are compatible with each other, and during firing, in the range of 0.05 to 0.5 molti, they form a solid solution in the pre-wall of microcrystals mainly composed of strontium titanate, and the atoms By controlling the resistance, the resistance of the sintered body was able to be in the range of 0.2 to O.SΩ·m. Even if the amount exceeds this range, the specific resistance becomes large even without IP, and the surge resistance cannot be increased. Sample No. in the above table.

3,7 to 10, and 13 to 16 are included in the cylinder of the present invention, and the others are comparative examples.

Next, we made a circuit as shown in Fig. 2 using such an element, and examined the output situation with respect to the noise human power a shown in Fig. 6. The results were as shown in the output modulus curve in Fig. 5. I was able to suppress the noise. Incidentally, the small power situation of the conventional filter circuit shown in FIG. 3 is like the output modulus curve C in FIG. 6, and noise is not sufficiently removed. Further, although the conventional filter circuit including the varistor shown in FIG. 4 can obtain the same effect as the circuit shown in FIG. 2 using the Umako of the present invention,
There are many parts including varistors. In FIGS. 2 to 4, 4 is a child of the present invention, 5 is a coil, 6 is a capacitor, and 7 is a varistor.

As described above, the device of the present invention has an unprecedented complex function and can play the two roles of burr-proofing and capacitor at the same time.For example, it can simplify the conventional noise filter circuit, make it smaller, and It contributes to high performance, performance, and cost reduction, and it has great utility as it can be applied to prevent malfunction and destruction of microcomputer-controlled equipment in the future, and its industrial value is enormous. is 0

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a multifunctional device of the present invention, FIG. 2 is a circuit diagram of a noise filter circuit using a small number of elements of the present invention, FIGS. 3 and 4 are circuit diagrams of a conventional noise filter circuit, and FIG. 5
The figure is a diagram showing the situations of input noise and output noise corresponding to the circuits shown in FIGS. 2 to 4. 1... Sintered body of strontium tetanate semiconducting porcelain, 2.3... Electrode. Name of agent: Patent attorney Toshio Nakao and one other person II
I figure? Figure 2, 6 Figure 5 Kite) Skin iron (M)/f)

Claims (1)

[Claims] The ratio of the number of atoms of titanium and strontium is 0.97 to 1.
036, contains silicon oxide in the range of 0.01 to 1.0 mol-〇, and contains at least one element among niobium, tantalum, and neodymium as a valence control element, and the content is in the range of oxidized On the surface of a sintered body of strontium titanate-based semiconductor porcelain, the amount is in the range of 0.05 to 0.5 mol. A multifunctional device formed by forming more than a pair of electrodes.