JPH0787896B2 - Solid electrolyte membrane deposition equipment - Google Patents

Description

The present invention relates to a solid electrolyte membrane deposition apparatus, and in particular to a conventional EVD.
The present invention relates to a solid electrolyte membrane deposition apparatus capable of depositing a solid electrolyte membrane at high speed in a method-based apparatus.

[Prior Art] FIG. 3 shows, for example, Westinghouse.
se Electric Corporation) EVD method ESS S invented by AO Isenberg
ymp.Electrode Materials Processes Energy Conver.Sc
orage 77-6 (1977) P.572).

In the figure, reference numeral (1) is a quartz glass reaction tube, (2)
Is a graphite reaction tube, (3) is a halogen material (4)
Graphite tube containing, (5) fibrous graphite plug, (6) perforated graphite plug, (7)
And (8) are graphite rods and springs that push the granule bed through the plugs. Further, (9) is a porous substrate tube having an opening ratio of 30% and is supported by a dense support tube (12) by ceramic cement (13). (10) is an alumina tube for introducing water vapor into the porous substrate tube (9).

Next, the operation of this conventional device will be described.

First, the reaction gas Cl ₂ and the carrier gas Ar were introduced into the graphite tube (3), and the reaction MeO ₂ + 2C _(s) + Cl _{2 (g)} → MeCl _{2 (g)} + 2CO _{(g) was used} to produce zirconium (Zr) and yttrium. Chloride vapor of (Y) is generated and supplied to the reaction tube (2). At the same time, when water vapor is supplied to the inside of the porous substrate tube (9) through the alumina tube (10), a solid electrolyte membrane grows by a two-step reaction as shown in FIG. However, in FIG. 4, reference numeral I indicates the state after the reaction in the first stage, and II indicates the second state.
The state after reaction of the stage is shown.

To describe this reaction, first, the water vapor inside the porous substrate tube (9) passed through the pores of the porous substrate tube (9), and at the surface of the porous substrate tube (9), Zr in chloride vapor was introduced. And reaction with Y chloride (first stage CVD reaction) A solid film is formed by MeCl ₂ + H ₂ O → MeO + 2HCl to close the pores.

Next, because the electronic conductivity appears in the solid film due to the difference in oxygen partial pressure, as shown in the reaction H ₂ O + 2e ⁻ → H ₂ + O ⁼ HeCl ₂ + O ⁼ → MeO + Cl ₂ + 2e ⁻ in the _second step, The H ₂ O is reduced by the electrons appearing on the surface of the generated solid film on the water vapor side, and oxygen ions (O ²⁻ ) generated thereby are diffused to the surface of the grown film to continue the reaction.

As an example of the deposition rate at this time, the pressure is 5 Torr or less and the deposition temperature is yttria-stabilized zirconia (Yttrium-stabilized zirconia).
Stabilized Zirconia) Deposition rate of 0.5 to 2 at 1200 ℃
It is about μm / min.

[Problems to be Solved by the Invention] The solid electrolyte membrane obtained by the EVD method, which is a conventional solid electrolyte membrane deposition technique, has an advantage that it is denser than solid electrolyte membranes obtained by other methods. The electron transfer rate of is controlling the deposition rate, and the deposition rate is 0.5
There is a problem that it is about 2 μm / min and it is slow to be industrialized, and there is a problem to solve this problem.

The present invention has been made to solve the above problems, by increasing the moving speed of electrons in the reaction region,
An object is to obtain a solid electrolyte membrane deposition apparatus capable of high-speed deposition.

[Means for Solving the Problem] A solid electrolyte membrane deposition apparatus according to the present invention is provided with a 2 mm external reaction tube (1) of a conventional solid electrolyte membrane deposition apparatus using the EVD method.
A plasma is generated in the reaction chamber on the metal compound gas side by providing a book electrode ring, and the probe electrode is introduced into the plasma,
At the same time, a porous electrode is provided on the metal compound gas side surface to form an external electron current circuit surrounding the growing solid electrolyte membrane.

[Operation] Since the device of the present invention is configured as described above, an external circuit of electrons is formed by the plasma, the probe electrode, and the porous electrode, and the moving speed of the electrons increases, so that oxygen Ion (O ^2- ) diffusion and charge-up due to reaction are easily eliminated, and the deposition rate increases.

[Embodiment] The present invention will be described below with reference to the drawings showing an embodiment thereof.

FIG. 1 is a diagram showing an embodiment of the present invention, in which reference numerals (1) to (13) are the same as or equivalent to those shown in the conventional apparatus by the same reference numerals.

Reference numeral (14) is two on the outer circumference of the quartz glass reaction tube (1),
Electrode ring, for example Pt electrode ring, provided so as to include the porous substrate tube (9) inside both of them, (15) is a 13.56MHz radio frequency (RF) power source connected to this Pt electrode ring (14) (16) is a probe electrode inserted in the plasma, and (17) is a porous electrode provided on the outer surface of the porous substrate tube (9). An external electronic current circuit is formed by the quality electrode (17). Also,
(18) Call and (19) are an ammeter and a variable resistor provided in this circuit. The quartz glass reaction tube (1) and the Pt electrode ring (14) are all located in a furnace capable of overheating to about 1100 ° C.

In the solid electrolyte deposition apparatus of the present invention configured as described above, two units of the 13.56 MHz high frequency power source (15) are used.
High frequency power is input to the Pt electrode ring (14) to generate plasma.

When chloride vapor and water vapor are supplied to the outer side and the inner side of the porous substrate tube (9) respectively, up to the first-stage CVD method, the instep is embedded in substantially the same procedure as in the conventional EVD method.

In the second-step reaction, the oxygen supplied on the inner surface of the electrolyte membrane is adsorbed and decomposed to generate oxygen ions.

The oxygen ions move to the outer surface of the electrolyte membrane by diffusion in the solid electrolyte, and further release electrons on the surface to form a metal oxide film by the reaction MeCl ₂ + O ⁼ → MeO + Cl ₂ + 2e ⁻ .

The emitted electrons easily move to the inside of the electrolyte membrane through the external electron current circuit formed by the plasma electrode without being charged up, so that the vapor metal oxide solid electrolyte membrane formation reaction proceeds rapidly. . On this occasion,
The film growth rate can be controlled by measuring the amount of current flowing through the external electronic current circuit with an ammeter and adjusting the amount of current using a load resistance.

In addition, in the above embodiment, in order to generate plasma,
A single electrode ring (14) is used, but it can be replaced by an electrode that is cut vertically into a cylinder, and the two electrodes can be installed above and below the reaction tube near the reaction chamber. Can be generated.

Further, in the above-mentioned embodiment, the base body for growing the solid electrolyte membrane was formed into a cylindrical tube, but the present invention is not limited to this, and it may be a flat plate, in which case the same effect as that of the above-mentioned embodiment can be expected. Needless to say.

In the above description, the invention of the solid electrolyte membrane deposition apparatus has been described with respect to the solid electrolyte membrane deposition technology, but it can also be used as the oxygen sensor manufacturing technology.

If an ammeter and a variable resistor are provided in the external electronic current circuit as in this embodiment, the film growth rate is measured by measuring or controlling the current flowing in the circuit, or Has the effect of being controllable.

[Advantages of the Invention] The present invention is configured as described above, generates plasma in the reaction space on the metal workpiece gas side, and provides a probe electrode on the generation part, and at the same time, on the metal compound gas side surface. Since the external electrode current circuit surrounding the solid electrolyte membrane is formed by providing the porous electrode, the film growth rate can be increased, and even if the temperature of the reactant is lowered as compared with the conventional method, the same level of film can be obtained. A growth rate is possible, and further, even if the oxygen partial pressure of the reaction chamber on the outer surface of the porous substrate is not so low, the effect of well suppressing the leakage of oxygen can be exerted.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of the present invention, FIG. 2 is a detailed view of the porous substrate tube (9) and porous electrode (17) of FIG. 1, and FIG. 3 is a conventional EVD method. FIG. 4 is a longitudinal sectional view showing a reaction apparatus used in FIG. 4, and FIG. 4 is an explanatory view showing the principle of the EVD method of FIG. In the figure, (1) is a quartz glass reaction tube, (3) is a graphite tube, (4) is a halogen material, (9) is a porous substrate (porous substrate tube), and (14) is an electrode ring (Pt electrode). Ring), (15) high frequency power supply, (16) probe electrode, (1
7) is a porous electrode, (18) is an ammeter in an external electronic current circuit, and (19) is a variable resistor in the circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A metal compound gas such as zirconium or yttrium is supplied to one space partitioned by a porous substrate, and oxygen is supplied to the other space, so that a solid is produced by a difference in oxygen partial pressure between both surfaces of the porous substrate. Oxygen ion (O ²⁻ ) is diffused in the electrolyte membrane to grow a metal oxide solid electrolyte membrane on the metal compound gas side surface of the porous substrate, which is based on the electrochemical deposition method (EVD method). In, a solid electrolyte membrane is grown by generating plasma in the reaction space on the metal compound gas side and providing a probe electrode on the generation part and simultaneously providing a porous electrode on the surface of the metal compound gas side porous substrate. A solid electrolyte membrane deposition device, characterized in that an external electronic current circuit surrounding the device is formed.