JPH10147881A - Atmospheric pressure discharge method and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge method in which any expensive incidental equipment is not required for discharge and the need of fabricating complicated electrodes is eliminated and by which atmospheric pressure discharge can be performed with a small electric power and also to provide the device for the discharge method. SOLUTION: This discharge method comprises applying a voltage to between a cathode and an electrode placed on an insulator, under the atmospheric pressure by using the device for the method. At this time, the device has a structure such that an anode 2 and a cathode 3 are placed on one side of an ion conductor 1 and on the other side of the ion conductor 1 respectively and further, an insulator 4 is placed on the anode 2 and an electrode 5 is placed on the insulator 4 and also, ion passage holes 5' are formed through the insulator 4 and the electrode 5 to enable movement of ions of the anode 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an atmospheric pressure discharging method and an apparatus used therefor.

[0002]

2. Description of the Related Art Various methods and apparatuses have been developed for the purpose of glow discharge under atmospheric pressure or higher. For example, in Japanese Patent Application Laid-Open No. 5-275191, an electrode of a conductor is arranged concentrically in a cylindrical shape, and a cylindrical insulator having a high dielectric constant is concentrically arranged in a gap between the electrodes so as to be in contact with the outer electrode. By inserting a gas mainly composed of a rare gas into the gap between the insulators in a state of being sent at an atmospheric pressure, and applying an AC electric field between the electrodes to ionize the gas mainly composed of the rare gas. An atmospheric pressure discharge method for generating plasma is disclosed.

In Japanese Patent Application Laid-Open No. 4-168281, a film-forming material is arranged in a discharge space formed between a high-voltage electrode and a ground electrode or in a ground electrode side, and a high voltage is applied between the electrodes. Atmospheric pressure glow for forming a film by introducing a monomer gas or a reactive gas consisting of a plasma gas and an inert gas according to the type of film into discharge gaps where glow discharge or silent discharge occurs near atmospheric pressure An atmospheric pressure glow plasma device is disclosed in which at least one of a high-voltage electrode and a ground electrode is formed of a conductive mesh electrode in a plasma discharge device, and a reaction gas is supplied to a discharge space from outside the mesh electrode. I have.

[0004] However, each of these discharge methods and devices requires a device for supplying a high frequency and high voltage, and furthermore, whether each of the dielectric and the electrode has a complicated structure, and whether or not the discharge is performed under atmospheric pressure. In order to stabilize the glow discharge in the discharge electrode, complicated measures have been taken on the discharge electrode. Therefore, there is a problem in terms of cost, complexity and size of the apparatus, and a large amount of power is required.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned expensive auxiliary equipment for electric discharge, to manufacture complicated electrodes, and to reduce atmospheric pressure discharge with small electric power. It is an object of the present invention to provide a method and apparatus for generating an atmospheric pressure discharge.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by using an ion conductor equipped with a pair of electrodes, expensive auxiliary equipment and expensive The inventors have discovered that stable discharge can be generated under atmospheric pressure without using a rare gas and without using a complicated electrode, and further research has led to the completion of the present invention. That is, the gist of the present invention is that (1) an anode electrode is provided on one side of an ion conductor and a cathode electrode is provided on the other side of the ion conductor;
Further, an apparatus having a structure in which an insulator is provided on the anode electrode, an electrode is provided on the insulator, and an ion flow hole is provided through the insulator and the electrode to allow movement of ions of the anode electrode. A discharge method characterized in that a voltage is applied between the cathode electrode and the electrode on the insulator under atmospheric pressure by using: (2) an ion conductor; and a discharge method provided on one of the ion conductors Having an anode electrode and a cathode electrode provided on the other side of the ion conductor,
Further, an insulator is provided on the anode electrode, and an electrode is provided on the insulator, and an ion flow hole penetrating the insulator and the electrode is provided, and between the cathode electrode and the electrode on the insulator. An atmospheric pressure discharge generator having voltage applying means for applying a voltage, (3) the ion conductor is zirconium oxide, cerium oxide, calcium oxide, manganese oxide, yttrium oxide, titanium oxide,
The atmospheric pressure discharge generator according to the above (2), which is a metal oxide selected from the group consisting of and barium oxide, or a solid solution of yttrium oxide in zirconium oxide.
(4) The atmospheric pressure discharge generator according to the above (2) or (3), wherein the ion conductor has a thickness of 1 to 5000 μm, and (5) a means for controlling the temperature of the ion conductor. The atmospheric pressure discharge generator according to any one of (2) to (4), wherein (6) the insulator on the anode electrode is alumina oxide, quartz glass, mullite, steatite, forsterite, or beryllia. 2)
(5) The atmospheric pressure discharge generator according to any of (1) to (5), wherein the thickness of the insulator on the anode electrode is 1 to 50 μm.
The atmospheric pressure discharge generator according to any one of the above (2) to (6).

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The device of the present invention has an ion conductor, an anode electrode provided on one side of the ion conductor, and a cathode electrode provided on the other side of the ion conductor. An insulator is provided on the anode electrode, an electrode is provided on the insulator, and an ion flow hole penetrates the insulator and the electrode; and the cathode electrode and the electrode on the insulator are provided. An atmospheric pressure discharge generator having voltage applying means for applying a voltage to an ion conductor, wherein an insulator having perforations is provided on an anode electrode provided on an ion conductor, and an electrode is provided on the insulator. It features that.

[0008] The ion conductor used is not particularly limited as long as it has the property of conducting various ions.
Preferably, it is a metal oxide or a metal oxide obtained by dissolving different types of metal oxides, and has a fluorite type structure or a perovskite structure. For example, cerium oxide, thorium oxide, zirconium oxide, hafnium oxide, bismuth oxide, strontium oxide, cobalt oxide, manganese oxide, and titanium oxide, and these metal oxides include magnesium oxide, calcium oxide, scandium oxide, yttrium oxide, and lanthanum oxide. , Niobium oxide, tungsten oxide, neodymium oxide, samarium oxide, cadmium oxide, cobalt oxide, cerium oxide, barium oxide, erbium oxide, and ytterbium oxide. Among them, zirconium oxide, cerium oxide, calcium oxide, manganese oxide, yttrium oxide, titanium oxide, and barium oxide are preferably used, and more preferably, zirconium oxide in which yttrium oxide is dissolved is used.

The shape of the ion conductor is not particularly limited, but may be any shape having a substantially constant thickness such as a plate or a tube. The thickness of the ion conductor is usually 1 to 5000 μm, preferably 50 to 2 μm.
000 μm. Thicknesses smaller than 1 μm are difficult to fabricate, there are many holes through which molecular oxygen is permeable, and they tend to break due to rapid temperature changes and have problems in strength. On the other hand, if the thickness is more than 5000 μm, good oxygen ion permeability cannot be seen. Examples of a method for manufacturing the ion conductor include a firing method, a plasma spraying method, a sol-gel method, a vacuum evaporation method, and sputtering, but are not limited thereto.

The apparatus of the present invention has a structure in which an anode electrode is provided on one side of an ion conductor and a cathode electrode is provided on the other side, and an insulator is provided on the anode electrode. For example, alumina oxide, quartz glass, mullite, steatite, forsterite, beryllia and the like are used. Although a thinner insulator is more advantageous in terms of discharge voltage as it is thinner, it is preferably 1 to 50 μm, more preferably 1 to 5 μm in view of film forming conditions.

The device of the present invention has a structure in which an electrode is further provided on an insulator. As the electrode material, a material having sufficient conductivity and a smaller thickness are more advantageous. It should be noted that the electric conductivity condition and the electrode preparation condition are 0.1 to 50 μm.
m is preferred, and more preferably 0.1 to 5 μm.

Specifically, the above-mentioned electrode material is a material having sufficient conductivity as an electrode material, for example, metals such as gold, platinum, silver, copper, iron, aluminum, nickel, zinc, and lead. And alloys composed of two or more metals or carbon. As the form of the electrode, a method in which an electrode material is formed into a paste and applied to a solid surface, or a method obtained by coating the solid surface by a sputtering method or a vacuum deposition method is used.

The device of the present invention is characterized in that it has an ion flow hole penetrating the insulator and the electrode as described above, and allows the movement of ions of the anode electrode through the ion flow hole. The size of the ion flow pore is preferably 0.01 to 100 μm, more preferably 0.1 to 100 μm.
10 μm. If it is less than 0.01 μm, the ions tend to collide with the hole wall surface and be deactivated. If it is more than 100 μm, the distance between the anode electrode and the electrode on the insulator and the hole diameter ratio become large, and it becomes difficult to maintain stable discharge. The device of the present invention further includes voltage applying means for applying a voltage between the cathode electrode and the electrode on the insulator. The voltage may be either AC or DC. In the device of the present invention, the anode electrode side and the cathode electrode side may be open to the atmosphere. However, in order to construct a structure for isolating a discharge generation field, the cathode electrode side and the anode electrode side are independently provided, and the anode side is rarely provided. Flowing a gas or the like has no problem in performing atmospheric pressure discharge. The structure that isolates the discharge generation field in this way
This is useful because a closed space is required when a discharge field is used for the reaction. With the above configuration, a stable discharge can be generated under the atmospheric pressure. Therefore, it is not necessary to use a conventional discharge tube, an expensive rare gas, an expensive power supply, and complicated electrodes.

A method for performing atmospheric pressure discharge using the apparatus of the present invention will be described below. The cathode electrode side of the ion conductor of the device of the present invention maintains the state where oxygen is present, and the anode electrode side allows passage of a flowing gas such as air or a rare gas when moving the discharge gas. . The flowing gas is preferably circulated from the viewpoint of renewing the surface of ions, molecules and the like adsorbed on the anode electrode. The ion conductor is set at an arbitrary temperature by a heater and a temperature controller. The temperature used is preferably 100 to 600 ° C, and 200 to 400 ° C.
Is more preferably set to. If the temperature is lower than 100 ° C., ionic conduction is not sufficient and it is difficult to maintain discharge,
If the temperature exceeds 600 ° C., the discharge is likely to be transferred to an arc. Further, a voltage is applied between the cathode electrode and the electrode on the insulator under atmospheric pressure. The discharge starting voltage at this time depends on the kind of flowing gas on the anode electrode side, but in order to maintain a good discharge state, a voltage of 100 V / cm or more, preferably 500 V / cm or more may be applied. The voltage can be both AC and DC.

[0015] The discharge mechanism in the discharge method of the present invention is based on the ease with which electrons are emitted from the ionic conductor.
The relationship between the ease of emission of the electrons and the discharge conditions is shown below.

The ion conductor has the property that oxygen ions move through oxygen lattice defects in the conductor crystal structure. Oxygen molecules are dissociated into oxygen atoms on the cathode electrode of the ion conductor, and electrons are given to O ^-2 . Oxygen ions enter into lattice defects of the ion conductor and move through the ion conductor. On the anode electrode side of the ion conductor, the oxygen ions that have moved are adsorbed on the electrode. Then, since the electrode on the insulator is a positive electrode, electrons of oxygen ions on the anode electrode filled with negative charges are attracted to the positive electrode to cause electron departure. Furthermore, the electrons accelerated between the electrodes ionize oxygen molecules or rare gas existing in the space between the electrodes, and emit more electrons. This phenomenon is generally called a continuous discharge phenomenon.

Generally, as a condition for generating a discharge, Townsend's spark condition, which is a condition for spark discharge when J is infinite (J → ∞), when the total current density is J, is known. If this is expressed by a formula,

[0018]

(Equation 1)

## EQU1 ## That is, the condition that J becomes infinite is that the denominator of eq-1 becomes zero, that is,

[0020]

(Equation 2)

Satisfying this condition is necessary for J to be infinite. Here, α represents the impact ionization coefficient, that is, the average number of times that one electron ionizes gas molecules by collision while the electron moves in the direction of the electric field, and γ is the secondary electron emission coefficient, that is, one ion or electron. Represents the number of secondary electrons emitted by colliding with the cathode, and L represents the distance of the discharge space.

By using an electrode (anode electrode) provided on the ion conductor, ions or electrons existing in the air or rare gas accelerated between the electrode and the insulator are attached to the surface of the ion conductor. Since a large amount of electrons are emitted by colliding with the oxygen ions adsorbed on the anode electrode, γ in the above equation increases. Accordingly, since α is almost close to 0 and the above condition is easily satisfied, the discharge is started under the atmospheric pressure, and a stable discharge is obtained in a steady state.

Therefore, by using an ion conductor, the γ value in the above equation becomes large, and discharge at atmospheric pressure is enabled.

[0024]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.

Embodiment 1 FIG. 1 shows a schematic configuration diagram of the atmospheric pressure discharge generator of the present invention used in Embodiment 1. 1 is an ion conductor made of Nikkato 8 mol% YSZ disk (50 mm diameter,
1 mm thick). Reference numerals 2 and 3 denote an anode electrode and a cathode electrode, respectively. Gold electrodes (thickness: about 2 μm) formed by physical vapor deposition were formed on both sides of the YSZ disk. Reference numeral 4 denotes an insulator formed by a CVD method, which is a thin film of alumina oxide (thickness: 2 μm). Reference numeral 5 denotes a platinum electrode having a thickness of 2 μm which is physically deposited on a thin film of alumina oxide. An ion flow hole 5 'was formed in the anode electrode structure thus prepared using an electron beam. The diameter of the hole drilled by the electron beam was 1 micron. The above-mentioned structure thus prepared is subjected to heating and temperature control 8 by 30
It was kept at 0 ° C. Subsequently, 0.2, 0.5, 1, between the cathode electrode 3 on the ion conductor and the electrode 5 on the insulator.
2, 5 V was applied discontinuously. The current generated at that time was measured by the ammeter 7. FIG. 2 shows the obtained results. When an applied voltage of 2 V was applied, a current of about 1 mA was generated, and plasma was generated near the anode electrode. As shown in this example, the discharge starting voltage is higher in the presence of air than in the presence of a rare gas (Example 2).

Embodiment 2 FIG. 3 shows a schematic configuration diagram of the atmospheric pressure discharge generator of the present invention used in Embodiment 2. 1 is an ion conductor made of Nikkato 8 mol% YSZ disk (50 mm diameter,
1 mm thick). Reference numerals 2 and 3 denote an anode electrode and a cathode electrode, respectively. Gold electrodes (thickness: about 2 μm) produced by physical vapor deposition were formed on both sides of the YSZ disk. Reference numeral 4 denotes an insulator formed by a CVD method, which is a thin film of alumina oxide (thickness: 2 μm). Reference numeral 5 denotes a platinum electrode having a thickness of 2 μm which is physically deposited on a thin film of alumina oxide. An ion flow hole 5 'was formed in the anode electrode structure thus prepared using an electron beam. The diameter of the hole drilled by the electron beam was 1 micron. The structure was maintained at 300 ° C. by a heater and a temperature controller 8 provided with the above structure. Also, the anode electrode structure side was covered with a glass reactor 10, and rare gas helium was allowed to flow using a He gas cylinder 9 by enabling the shield from outside air. Subsequently, 0.01, 0.0 between the cathode electrode 3 on the ion conductor and the electrode 5 on the insulator.
5, 0.1, 0.2 and 0.5 V were applied discontinuously.
The current generated at that time was measured by the ammeter 7. FIG. 4 shows the obtained results. By applying an applied voltage of 0.1 V or more, a current of about 5 mA flowed and plasma was generated near the anode electrode.

[0027]

According to the present invention, a stable discharge can be generated at atmospheric pressure without using expensive auxiliary equipment or expensive rare gas, and without using complicated electrodes.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an atmospheric pressure discharge generator of the present invention used in Example 1. FIG.

FIG. 2 is a diagram illustrating a relationship between an applied voltage and a current obtained in Example 1.

FIG. 3 is a schematic configuration diagram of an atmospheric pressure discharge generator according to the present invention used in Example 2.

FIG. 4 is a diagram illustrating a relationship between an applied voltage and a current obtained in Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ion conductor 2 Anode electrode 3 Cathode electrode 4 Insulator 5 Electrode 5 'Ion circulation hole 6 Power supply 7 Ammeter 8 Heater and temperature controller 9 He gas cylinder 10 Glass reactor

Claims (7)

[Claims] An anode electrode on one side of the ion conductor;
On the other side, a cathode electrode is provided, and further, an insulator is provided on the anode electrode and an electrode is provided on the insulator,
Using an apparatus having a structure in which an ion flow hole penetrating through the insulator and the electrode is provided to enable the movement of ions of the anode electrode, between the cathode electrode and the electrode on the insulator under atmospheric pressure. A discharging method characterized by applying a voltage. 2. An ion conductor, an anode electrode provided on one side of the ion conductor, and a cathode electrode provided on the other side of the ion conductor. Voltage applying means provided with an insulator, provided with an electrode on the insulator, provided with an ion flow hole penetrating the insulator and the electrode, and applying a voltage between the cathode electrode and an electrode on the insulator. An atmospheric pressure discharge generator, comprising: 3. The method according to claim 1, wherein the ionic conductor is a metal oxide selected from the group consisting of zirconium oxide, cerium oxide, calcium oxide, manganese oxide, yttrium oxide, titanium oxide, and barium oxide, or a solid solution of yttrium oxide in zirconium oxide. 3. The atmospheric pressure discharge generator according to claim 2, wherein: 4. The atmospheric pressure discharge generator according to claim 2, wherein the ionic conductor has a thickness of 1 to 5000 μm. 5. The atmospheric pressure discharge generator according to claim 2, further comprising means for controlling the temperature of the ion conductor. 6. The atmospheric pressure discharge generator according to claim 2, wherein the insulator on the anode electrode is alumina oxide, quartz glass, mullite, steatite, forsterite or beryllia. 7. The thickness of the insulator on the anode electrode is 1 to 5
The atmospheric pressure discharge generator according to any one of claims 2 to 6, wherein the diameter is 0 µm.