JPS607706A - Method of producing 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] Industrial Field of Application The present invention relates to an MtL method for a multi-functional element having both a varistor function and a capacitor function. - The structure of the conventional example and its problems. There are SiC varistors and varistors whose main component is zinc oxide as ceramics with linear resistance characteristics.The current knee voltage V characteristic of such varistors is approximately expressed as v(I I=()) Here, C is a constant specific to the varistor, and is a voltage nonlinear index of α company.

The SiC varistor utilizes a contact barrier between SiC particles, and has a voltage nonlinearity index α of about 2 to 7. In addition, zinc oxide varistors are made by adding B 1 to zinc oxide (ZnO,).
203. This is an element obtained by adding a small amount of metal oxide such as C002Mno2, 5b203 and firing, and the voltage nonlinearity index α is as high as 50. Since such elements have excellent performance in absorbing high voltages, they are used for the purpose of stabilizing electronic equipment and protecting against abnormal high voltages (surges). However, such conventional varistors have a small dielectric constant and a dielectric loss angle (
Since the tan δ) is as large as 6 to 10%, it can only be used for varistors.

On the other hand, as capacitors, dielectric ceramics whose main components are barium titanate (Ba'riO3) and strontium titanate (SrTiO3), which have large dielectric constants, are widely used in electronic circuits as small, large-capacity capacitors. . However, if a current of 1 mA or more flows through the element, it will be destroyed and lose its function as a capacitor.

In recent years, electronic equipment has come to require extremely sophisticated control, and not only industrial equipment but also microcomputer applications and consumer equipment have come to require extremely high precision. Furthermore, since logic circuits constituting microcomputers and the like operate a lot based on pulse signals, they inevitably have the disadvantage of being susceptible to noise. For this reason, electronic computers.

Banking machines, traffic control equipment, etc., can become a social problem if they malfunction or are destroyed due to noise or surges. Noise filters have conventionally been used as a countermeasure to such problems. Noise refers to interference voltage other than the intended signal voltage when operating electronic equipment, and is 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, artificially generated noise, especially those caused by the opening and closing of circuit breakers on power transmission lines, and noise caused by natural phenomena, especially those caused by lightning, have low fundamental frequencies.
~20 KHz, and it was not possible to eliminate these noises using only the conventional combination of a coil and a capacitor. 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. Such a noise filter can remove a very wide range of noise, and is therefore effective in preventing malfunctions of microcomputer-controlled equipment.

However, such a noise filter has a large number of parts inside the set, and is expensive.
It had the disadvantage of going against the technological trend of miniaturization.

OBJECTS OF THE INVENTION In view of the above-mentioned drawbacks, an object of the present invention is to provide a method for manufacturing a multi-functional element that can inexpensively produce a multi-functional element having both a varistor function and a capacitor function.

Structure of the Invention In order to achieve this object, the method for manufacturing a multi-functional device according to the present invention is to apply finely pulverized powder of a sintered body of dielectric ceramic that can be used as a ceramic capacitor to a smudged nonlinear material using a plasma spraying method. It is sprayed onto the surface of a resistor through an electrode to form a dielectric with a capacitor function, and the element obtained by this method has the combined function of a varistor and capacitor, so it is different from conventional varistors and capacitors. A single element can serve the purpose in a circuit that connects these elements in parallel.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a multifunctional device obtained by the method of the present invention, and FIG. 2 is an equivalent circuit thereof.

In the figure, 1 is a voltage nonlinear resistor, 2a and 2b are electrodes, 3 is a dielectric, and 4 is an electrode connected to the electrode 2b. Further, 6 is a varistor, and 6 is a capacitor.

First, S r O, Sn was added to the B a T 10s powder.
0.01-1.0 mol of each of O2r, Zr, and O2 were added and mixed thoroughly. This was molded to a diameter of 25 m and a thickness of 6 mm, and fired at a temperature of 1200 to 1300°C for 1 to 3 hours. Next, the sintered body was pulverized to produce fine dielectric powder. The average particle size is approximately 20 μm. Next, a voltage non-linear resistor 1 mainly composed of zinc oxide with electrodes 2a and 2b formed on both planes is prepared, and fine powder of the above dielectric is sprayed on one plane side by plasma spraying. 3
was formed. After that, an electrode 4 is attached to one side of the dielectric 3.
b to obtain a multifunctional device. In addition, in the plasma spraying method, the oxide is melted at high temperature using an electric arc, and at the same time it is blown away using high-pressure inert gas.
This is a method in which a film is formed by attaching it to an object. The spraying conditions in this example were 6o~80KW and the spraying distance was 10
cm, Ar was used as an inert gas.

The shape of the multifunctional device obtained in this way is 1Q oboroψ,
The thickness of the dielectric material was 100 μm to 1 inch. In addition, the performance is as follows: capacitance: 3 to 10 nF, tan δ: 2%, varistor voltage: 1 oov, α: 40. The surge resistance was 1000A. Here, the capacitance is variable by changing the plasma spraying time.

Further, the thermal spraying time in the example is 30 seconds to 2 minutes.

Although the material and forming method for the electrodes are not limited, a baking method is preferable in order to remove internal distortion of the dielectric caused by plasma spraying.

Further, although a zinc oxide varistor was used as the voltage nonlinear resistor, any sintered body having voltage nonlinear characteristics is effective in view of the effects of the present invention.

Further, although B a TiOa ceramics were used as the dielectric material, any ceramic fundenza material that can be formed into a dielectric material by plasma spraying is effective in view of the effects of the present invention.

Effects of the Invention As described in detail above, the method for manufacturing a multi-functional device according to the present invention can easily perform both functions of a capacitor and a varistor by forming a dielectric material on the surface of a voltage non-linear resistor by plasma spraying. It is possible to provide an element having the following characteristics, and its practical value is great as a noise countermeasure component for electronic equipment.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a multifunctional device obtained by the method of the present invention, and FIG. 2 is a diagram showing its equivalent circuit. 1... Voltage nonlinear resistor, 2a, 2b...
...electrode, 3...dielectric, 4...electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (1)

[Claims] Manufacture of a multifunctional device characterized by finely pulverizing a sintered body of dielectric ceramic and spraying the powder onto the surface of a voltage nonlinear resistor via an electrode using a plasma spraying method to form a dielectric. Method.