JPH0222476A - Production of zirconia film - Google Patents

Abstract

PURPOSE:To form a ZrO2 film having superior corrosion, heat and wear resistances and insulating property by subjecting a mixture of tetrabutoxy zirconium or zirconium octylate with an acetyl compd. to hydrolysis and dehydration condensation, coating the surface of a stainless steel sheet, etc., with the resulting sol and drying the sol. CONSTITUTION:Tetrabutoxy zirconium or zirconium octylate is dissolved in an org. solvent such as butanol or isobutyl alcohol at 1mol/l concn. An acetyl compd. represented by a general formula CH3CO-(CH2)n-COCH3 (where n is 1-6), e.g., acetylacetone or diacetylethane is added to the resulting soln. at 2-0.5mol/l concn. Water is further added at 2-7mol/l concn. and hydrolysis and dehydration condensation are carried out to prepare sol. The surface of a stainless steel sheet, etc., is coated with the sol and heated at >=200 deg.C to form a ZrO2 film having superior characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing a zirconia membrane using tetrabutoxyzirconium or zirconium octylate.

(Prior technology) Norconi 7 (zirconium oxide) has excellent corrosion resistance, heat resistance, abrasion resistance, insulation, etc., so it is possible to improve the properties by forming a zirconia film on a conventional material that has poor properties. method is being carried out.

As a wet method for forming this zirconia film, there is a method in which an organic solvent solution of alkoxynorconium such as tetrabutoxyzirconium is applied to a substrate, and hydrolysis and dehydration condensation are carried out (Japanese Patent Publication No. 59-48865), and a method in which an organic solvent solution of norconium octylate is applied. Method of coating and thermal decomposition (4!
-41770) etc. have been developed.

(Problems to be Solved by the Invention) However, in the former method, the hydrolysis and dehydration condensation reaction rates of alkoxyzirconium are relatively fast;
Since the reaction progresses due to moisture in the air, the concentration should be kept at about 0.
If an attempt is made to form a thick film with a single application by increasing the concentration to 0.05 mol/e or more, the zirconia film will be hydrolyzed by moisture in the air and become cloudy, making it impossible to obtain a transparent zirconia film.

As a method to increase the amount applied per application at low concentration,
One possible method is to increase the viscosity and concentration by hydrolyzing and solizing by adding water, but when hydrolyzed,
Because the hydrolysis rate is fast, it becomes cloudy and precipitates, making it impossible to obtain a transparent zirconia film.

Therefore, in order to form a transparent thick film, the concentration is 0.05.
1) 200 per application using a solution with mol/C or less
．． The method of forming a fulconia film with a thickness of less than 100 nm was repeated.

On the other hand, in the case of the latter method, the hydrolysis rate of zirconium octylate in air is slower than that of alkoxynorconium, and it does not become cloudy even when applied at a high concentration (approximately 259/e or higher). .

However, if the solution is left in the air for 2-3 days, gelation will occur. Therefore, there is no problem if the prepared solution is used in its entirety each time, but if a residual solution occurs, it cannot be reused unless it is used within a short period of time. Further, when norconium octylate undergoes hydrolysis and dehydration condensation by heating, the volume shrinks, which causes cracks in the zirconia film, resulting in poor appearance.

The present invention provides a method for manufacturing a zirconia film that solves the above problems.

(Means for Solving the Problems) The present invention provides an organic solvent solution of tetrabutoxyzirconium or zirconium octylate with the general formula CH*C0-(
After adding 0.5 mol or more of an acetyl compound represented by CH2)n-C0CH5 (n is 1 to 6) per 1 mol of tetrabutoxyzirconium or norphnium octylate, 2 to 7 mol of water is added to perform hydrolysis and dehydration condensation. A zirconia film was produced by applying the sol solution to a substrate and then heating it to 200° C. or higher.

In the present invention, the general formula CH3CO-(CH2)n-C0CH
The reason why the acetyl compound represented by 5 (n is 1 to 6) is added is to reduce the hydrolysis rate of tetrabutoxyzirconium or zirconium octylate, and to prevent the solution from becoming cloudy, precipitated, or delified. In other words, the carbonyl group of the acetyl compound coordinates with the norconium atom of tetrabutoxyzirconium* or zirconium octylate, so the LO molecule undergoes a nucleophilic reaction with norconium, and the 1120 molecules approach due to steric hindrance. Therefore, the hydrolysis rate is suppressed, and cloudiness, precipitation, and delification are prevented.

This hydrolysis suppressed ear product is general 2CH, C0-(CL
) n-〇, among the acetyl compounds represented by OCH co,
This is also observed when n is 7 or more, but when n is 7 or more, it becomes solid at room temperature and becomes difficult to dissolve, making it difficult to prepare a solution.

This acetyl compound prevents clouding and precipitation, and among alkoxynorconiums, such as tetra-n-butoxyzirconium and tetraisobutoxyzirconium,
It is effective only in the case of tetrabutquin norconium.

Zirconium tetramethoxide, tetraethoxide,
Tetra-n-propoxide or tetrane propoxide is hydrolyzed by an alkoxy group, resulting in white turbidity and precipitation.

If the acetyl compound is added in an amount of 0.5 mole or more per mole of tetrabutoxyzirconium or zirconium octylate, the rate of hydrolysis can be slowed down.

Hydrolysis after adding an acetyl compound is carried out by adding 2 to 7 moles of water to 1 mole of the norconium compound; however, if it is less than 2 moles, hydrolysis will be insufficient, and if it exceeds 7 moles, water will be added. This is because the remaining water causes pinholes and the like, which impairs the appearance.

Tetrabutoxyzirconium and zirconium octylate will form a zirconia film if heated above 200°C, but even if zirconium 7cetylacetonate is added to them, a 7cetyl compound will form a zirconia film if heated above 200°C. Therefore, the heating temperature may be 200°C or higher.

According to the invention, other metals (e.g. Ti5CoSNo,^
When producing a zirconia film containing a metal (e.g., Cu), it is possible to slow down the hydrolysis of the metal by adding tetrabutoxide or metal octylate as the metal raw material.

(Example) Example 1 To a 2009/e butylene solution of tetra-n-butoxynorconium, 7cetylacetone was added in an amount equivalent to 1 mole per mole of tetra-n-butoxynorconium and stirred. After that, tetra-n-butoxynorconium 1
Water in an amount equivalent to 4 moles per mole was added to carry out hydrolysis and dehydration condensation.

Next, a stainless steel plate (SUS304) that had been ultrasonically degreased at 77 tons was immersed in this solution, and the solution was applied to the stainless steel plate by pulling it up at a constant speed of 0.1 in/in. The film was placed in an electric furnace for 7 minutes to form a zirconia film.

The thickness of the obtained zirconia film was O9Zμ, and it was transparent without cloudiness or cracks.

On the other hand, a solution of 5119I was prepared in the same manner as described above without adding 7cetylacetone to tetralobtoxyzirconium
However, the solution instantly became cloudy and precipitated during hydrolysis.

Example 2 After adding diacetyl ethane to a 1509/e isopropyl alcohol solution of zirconium octylate in an amount equivalent to 6 moles per mole of norconium octylate,
Water was added in an amount equivalent to 5 moles per mole of norconium octylate to carry out hydrolysis and dehydration condensation. This solution was left in the air (relative humidity 60%, temperature 25° C.) for one week, but no change was observed.

Next, this standing solution was applied to a stainless steel plate by a spray method and heated at 400° C. for 10 minutes to form a zirconia film with a film thickness of 0.15 μm.

(Effects) As described above, when an acetyl compound is added to butoxyzirconium and subjected to hydrolysis and dehydration condensation, a transparent thick zirconia film can be produced without producing cloudiness or precipitation. Furthermore, when an acetyl compound is added to zirconium octylate, the storage stability of the solution is improved, and cracks due to dehydration condensation do not occur in the zirconia film.

Claims (1)

[Scope of Claims] An acetyl compound represented by the general formula CH_3CO-(CH_2)_n-COCH_3 (n is 1 to 6) is added to a solution of tetrabutoxyzirconium or zirconium octylate in an organic solvent by 1 mol of tetrabutoxyzirconium or zirconium octylate. After adding 0.5 mol or more, 2 to 7 mol of water was added to perform hydrolysis and dehydration condensation, and the sol solution was applied to the substrate, and then 20
A method for producing a zirconia film, which comprises heating to 0°C or higher.