JP2887308B2 - Manufacturing method of stabilized zirconia thin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a stabilized zirconia thin film. Here, this stabilized zirconia thin film exhibits high oxygen ion conductivity at high temperatures, and is therefore used as an oxygen sensor.
Further, in view of chemical stability at high temperature, high oxygen ion conductivity, and high strength, solid oxide fuel cells (Solid Ox
(ideFuel Cell: SOFC).

[0002]

2. Description of the Related Art As a typical example up to now, a method using a sintered body made of powder has been adopted, but the internal resistance (resistivity × thickness) becomes extremely large due to its thickness. Therefore, thinning has become an important issue. Therefore,
At present, an electrochemical deposition method (Electrical Deposition) that combines an electrochemical reaction with a gas phase method.
(n, EVD), a dense film having a film thickness of about 20 μm has been prepared, but the film thickness is not yet sufficiently thin, and there is still a problem in terms of cost.

[0003]

An object of the present invention is to provide a method for producing a stabilized zirconia thin film having high oxygen ion conductivity at high temperatures.

[0004]

In order to achieve the above-mentioned object, in the method for producing a stabilized zirconia thin film according to the present invention, M () is a hydroxide of a mixture of yttrium and zirconium using alcohol as a dispersion medium. A sol of OH) ₃ and M ′ (OH) ₄ (M = Y, M ′ = Zr) is prepared, and the obtained sol is gelled and simultaneously fired at 600 ° C. to 1300 ° C. It is assumed that.

[0005] Since the method for producing a stabilized zirconia thin film according to the present invention is constituted as described above, it is possible to control the chemical composition with high precision, which is called the sol-gel method, to have high homogeneity, and to have an arbitrary shape imparting property. By using a method that has the features of lowering the process temperature and simplicity of operation, it is possible to use sols and salts that use inorganic salts such as yttrium and zirconium chlorides and nitrates and organic acid salts such as acetates as raw materials. From the gel method, as shown in FIG. 3, when the ionic conduction of the enzyme is 600 ° C., log σ _{600 ° C.} (S / cm) = −
3. An excellent stabilized zirconia thin film of 5 can be produced.

[0006] At least one of the group consisting of organic acid salts and inorganic acid salts can be used as the raw material compound.

Further, at least one of the group consisting of ethanol, 2-butanol and ethylene glycol can be used as the alcohol.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a raw material compound for producing a yttrium or zirconium hydroxide in alcohol, an organic acid salt or an inorganic acid salt of these metals is suitable.

As specific examples of the stabilized zirconia compound suitable as a raw material compound, zirconyl chloride, zirconia acetate, zirconia nitrate and the like are used. Preferred specific examples of the yttrium compound include yttrium chloride,
Yttrium acetate, yttrium nitrate or the like is used.

As the alcohol for dissolving these starting compounds and then forming a sol, an appropriate alcohol can be arbitrarily selected depending on the type of the starting compounds.
Examples of suitable in many cases are ethanol, 2
-Propanol, ethylene glycol, acetylacetone, 2- (2-ethoxyethoxy) ethanol and the like.

When zirconyl chloride and yttrium chloride are used as raw materials, two methods are employed. The first method is to convert these raw materials into water, ethylene glycol and 2
-Dissolved in a mixture of butanol to form a coating solution. In the second method, a coating solution (sol) is prepared by dissolving these raw materials in ethanol and refluxing at about 80 ° C.

When the prepared sol is left as it is for a long time, it gradually undergoes dehydration-condensation polymerization and gels in a container, so that it is developed into a film before gelation. For example, dip coating, spin coating, spraying,
A suitable substrate (for example, an ultrasonic spray method)
Alkali-free glass, Vyrex glass, quartz glass,
(Plate of alumina, platinum, etc.).

[0013] The sol coated on the substrate gels to form a soft film when left to stand or when the water is gradually evaporated. After drying this gel film, it is fired to produce stabilized zirconia crystals. The required firing temperature is
It varies slightly depending on the raw materials used, but is about 600-1300
゜ C.

Approximately two hours of calcination is required to produce sufficient stabilized zirconia crystals. The thickness of the obtained thin-film stabilized zirconia ceramics can be controlled to about 0.05 to 0.1 μm by one dip coating, depending on the adjusted concentration of the coating solution. The substrate is dipped, pulled up, dried, baked at 500 ° C., and this operation is repeated to obtain a film having an arbitrary thickness (see FIG. 2).

According to the above manufacturing method, the chemical composition is xY ₂ O
In _{3 · (100-x) ZrO} 2, the value of x 2 to 2
It is possible to prepare an arbitrary thin film in which the thickness is changed to 0 mol%.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment will be described with reference to FIG. 1.4374 g of zirconium chloride / octahydrate and 0.2332 g of yttrium chloride / hexahydrate are weighed, and 1 ml of water,
It is dissolved in a mixed solvent of 3 ml of ethylene glycol and 2 ml of 2-butanol, and the mixture is stirred at room temperature for about 1 hr or more to prepare a coating solution (sol). The substrate (for example, alumina: Al ₂ O ₃ plate) is dipped in this solution, and 1c
Raise at m / min. After drying, the temperature is raised to 500 ° C. at a rate of about 5 ° C./min in an electric furnace, and about 1 hour
After the temperature is maintained, the temperature is rapidly raised to a predetermined temperature of 600 ° C. to 1300 ° C. and calcined for about 2 hours to obtain a stabilized zirconia thin film.

[0017]

Next, a second embodiment will be described. Weigh and weigh 1.2578 g of zirconium chloride octahydrate and 0.2041 g of yttrium chloride hexahydrate and 10 ml of ethanol
The mixture was dissolved under reflux and refluxed at about 80 ° C for 10 hours. After cooling, a coating solution was obtained. The substrate (eg, alumina: Al ₂ O ₃ plate) is dipped in this solution, pulled up at a pulling rate of 1 cm / min, dried, and heated at a rate of about 5
The temperature is raised to about 500 ° C. at about さ せ C / min and kept for about 1 hour, then rapidly raised to a predetermined temperature of 600 ° C. to 1300 ° C. and baked for about 2 hours to obtain a stabilized zirconia thin film. In each of Examples 1 and 2, a thin film having an arbitrary thickness can be obtained by repeatedly dipping the thin film kept at 500 ° C. for 1 hour. Further, in both Examples 1 and 2, the coating solution was dried to a predetermined temperature of 600 to
It is also possible to obtain powdered stabilized zirconia by baking at 1300 ° C. for 2 hours each.

[0018]

Since the method for producing a stabilized zirconia thin film according to the present invention is constituted as described above, the sol-gel method is used to control the chemical composition with high precision, to achieve high homogeneity, and to provide an arbitrary shape imparting property. By using a method that has the characteristics of lowering the process temperature and simplicity of operation, inorganic salts such as yttrium and zirconium chlorides and nitrates and organic acid salts such as acetates are used as raw materials. From the sol-gel method, as shown in FIG.
In ゜ C, log σ _{600 ° c} (S / cm) = −
An excellent stabilized zirconia thin film of 3.5 can be produced.

Therefore, by using this method for producing a stabilized zirconia thin film, the stabilized zirconia thin film can be formed by a simple operation, and its composition and shape can be easily changed. As a result, it is suitable for mass production of a stabilized zirconia thin film, and it is possible to inexpensively provide excellent stabilized zirconia exhibiting extremely high oxygen ion conduction at high temperatures.

[Brief description of the drawings]

FIG. 1 is a view showing operation steps when a thin film is formed using yttrium chloride and zirconyl chloride as raw materials.

FIG. 2 is a graph showing the relationship between the thickness of a thin film formed on an Al ₂ O ₃ substrate by dip coating from a coating solution prepared by the operation method of FIG. 1 and the number of times of dipping.

FIG. 3 shows the dependence of the conductivity log σ (S / cm) of Y ₂ O ₃ on the stabilized zirconia cap film prepared by heat treatment at 1300 ° C. for 2 hours at a temperature of 600 ° C. in air. It is a graph.

Claims (3)

(57) [Claims] 1. Hydrolysis of a raw material compound dissolved in alcohol to form a hydroxide of a mixture of yttrium and zirconium using alcohol as a dispersion medium.
(OH) ₃ and M ′ (OH) ₄ (M = Y, M ′ = Z
The stabilized zirconia excellent in chemical stability and strength at high temperature, characterized in that the sol of r) is prepared, and the obtained sol is gelled and fired at 600 ° C. to 1300 ° C. Manufacturing method of thin film. 2. The method for producing a stabilized zirconia thin film according to claim 1, wherein at least one of a group consisting of an organic acid salt and an inorganic acid salt is used as the raw material compound. 3. The method according to claim 1, wherein the alcohol is ethanol,
The method for producing a stabilized zirconia thin film according to claim 1, wherein at least one of a group consisting of butanol and ethylene glycol is used.