JPS61291977A - Production of thin film of lower vanadium oxide - Google Patents

Abstract

PURPOSE:To easily form a thin film of lower vanadium oxide at a low temp. by applying V2O5 hydrate gel to a substrate and heating or baking the substrate in a flow of a reducing gas at a specified temp. CONSTITUTION:V2O5 hydrate gel is diluted to about 10g/l concn., applied to a substrate such as a porcelain plate and dried by its own heat. The substrate is put in a heating furnace, where it is heated or baked at 70-700 deg.C, preferably 250-700 deg.C for about 30min-3hr while a reducing gas is fed. Gaseous NH3, CO, H2, SO2 or a gaseous mixture of two or more among them is used as the reducing gas. By this method, a thin film of lower vanadium oxide such as V2O3 or V2O4 can be formed on the surface of the substrate at such a relatively low temp. with a small amount of the reducing gas. The reducing reaction can be carried out under ordinary pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application] The present invention is used for forming thin films of vanadium lower oxides and for surface treatment.

[Conventional examples and problems]

Conventionally, it has been disclosed in JP-A-49-1 that V2O3 powder can be obtained from K by reducing ammonium metavanadate (NH4VO3) or VzOs powder with NH3 gas at 1 to 20 times (vanadium raw material molar ratio) at 450 to 700°C for 1 to 6 hours.
Although this method is known from No. 47294, a thin film cannot be formed.

Furthermore, a method of coating a VzOs hydrated gel on an insulating substrate and simply drying it is known from Japanese Patent Publication No. 57-29502. At this time, conductivity is imparted by the V4+ ions originally contained in the VzOs hydrated gel, and the temperature must be extremely strictly controlled at a high temperature during the production of the gel. The quantity will decrease and the cost will increase. Further, regarding the formation of a film after coating and drying, there is no description in this Japanese Patent Publication No. 57-29502, and as a result of additional tests, it was found that no film was formed as it was (although a separate film-forming agent must be added).

In addition, there is a method of putting V2O5 and a metal as a reducing agent together in a vacuum container, sublimating them, reducing them in a gaseous state, and taking out the generated VO2, V2O3, etc., which are cooled and solidified, as described in JP-A-50-7289 [ Problems to be Solved] The present invention is simple and uses a low-temperature reduction treatment to form a vanadium lower oxide film on the surface of the substrate.

[Means for solving problems]

In this invention, a VzOs hydrated gel is applied to a substrate, and heated or baked for about 30 minutes to 3 hours in a reducing gas flow of 70 to 700"C, preferably 250 to 700t", to remove the applied VzOs gel on the substrate. V2O5 hydrated gel V,OS
The problem was solved by creating a method for manufacturing a vanadium lower oxide thin film, which is characterized by forming a lower vanadium oxide thin film.

More specifically about the method of this invention! 52 will be revealed.

a) Production method of hydrated gel to V There is no % limit to the method of obtaining hydrated gel, but for example, V2O5 is placed in a crucible, melted, and maintained at a temperature slightly higher than the melting temperature by 100 to 150 t. After making it into a uniform molten state, it is quickly poured into pure water or a liquid containing about 10 to 30% of hydraulic acentone.
O5 hydrated gel was obtained and VzOs was added prior to use.
Dilute to a concentration of 10 f'/l.

b) The substrate to be coated is a glass, ceramic, synthetic resin plate, etc., such as a magnetic product material or a photographic product material, and has a melting point of 70''C or higher.

C) Coating methods include brush or roller coating, spraying, electrostatic coating, dipping, etc., which are included in the coating methods of this invention.

d) The heater used in the drying and heating method is not particularly limited as long as it can be isolated from the outside air, and it is best to use one that can adjust the heating temperature to the desired temperature, and an electric furnace is most convenient.

The heating temperature is below the melting temperature of the base.

First, the V2O1S hydrated gel described in item a) is applied to the surface of the substrate described in item b) by the coating method shown in item C).

The substrate coated with the V2O11 hydrated gel is placed in a heating furnace, the temperature in the heating furnace is adjusted to below the melting or deformation temperature of the substrate, and heated for 30 minutes to 3 hours to eliminate V in the surface of the substrate.
The 2O11 hydrated gel layer is reduced to form a vanadium lower oxide film such as V2O3 or V2O4 on the surface of the substrate.

〔effect〕

First of all, this method uses a method of applying V2O and hydrated gel to the substrate, so it is easy to apply, and since it is in a glue form, it can be applied not only to glass and ceramic surfaces, but also to various plastic surfaces. Can be applied to. Also V2O
Since 5 is an amorphous ultrafine particle with a size of several tens of OA, it has a high activity, and only a small amount of reducing gas is brought into contact with it, and the reduction temperature is relatively low and the reduction time is short. The vanadium produced is extremely high, and the lower oxide forms a film on the surface of the substrate.

Moreover, since the reduction reaction can be carried out at normal pressure (of course, the reaction can also be carried out under increased pressure or reduced pressure), continuous reaction in large quantities is also possible.

In particular, since it does not depend at all on K v2o and 4-F ions in the hydrated gel, there are no particular limitations on the manufacturing method for producing VzOs hydrated gel, and any method that provides a good yield of V2O5 hydrated gel can be selected. Therefore, the cost is low and it is extremely useful.

Experimental example 1 V2O550f was placed in a porcelain crucible and heated for 30 minutes in an electric furnace.
The melting point of V2O5 is kept at K for 800""c (690°C) for a minute. Then, the molten metal is quickly poured into lIt pure water.
Obtain a V2O5 hydrated gel, dilute it to a V2O5 concentration of 1%, use a porcelain plate (50x50R1) as a substrate, apply the above solution to the surface to a thickness of 100 μm over an area of 20x201EI, and let it air dry. After that, H is placed in the electric furnace.
570 for 1 hour while supplying 2 gas at 10xl/m
After the reaction at C, the temperature was lowered to room temperature, and the film formed on the surface of the substrate was confirmed by X-ray diffraction to be a thin film made mostly of V2O3.

Experimental Example 2 The same substrate as in Experimental Example 1 was coated with KV2O5 hydrated gel, and NHa gas was heated to 10 m in the same electric furnace as above.
When the reaction was carried out at 380° C. for 1 hour while being supplied at 1/2, a thin film of KVO2 was formed on the surface of the substrate.

Experimental Example 3 When the same product as in Experimental Example 1.2 was reacted for 2 hours at 240''C in an air flow of 5 xi/m using SO2 gas as the reducing gas, a thin film containing a mixture of V6O13 and V3O7 was obtained.

Experimental Example 4 (Comparative Experiment) When the same material as in Experimental Examples 1 to 3 was reacted in air at 300 t'' for 30 minutes without using reducing gas, a thin film of V2O5 was formed.

When dried, no film is formed on the surface and it is amorphous.
205 was formed to resist adhesion.

Further, using NH, H2, and SO2 as reducing gases, the approximate relationship between the reduction temperature and the oxides produced on the substrate surface is shown in the following table.

that's all Procedural amendment (voluntary) August 1985 - 1st

Claims (1)

[Claims] 1) Apply V_2O_5 hydrated gel to a substrate,
The V_2O_5 hydrated gel coated on the substrate is heated or baked in a reducing gas stream at 00°C, preferably 250 to 700°C, for about 30 minutes to 3 hours to convert the V_2O_5 hydrated gel coated on the substrate to V_2O_
A method for manufacturing a vanadium lower oxide thin film, which is a vanadium lower oxide thin film having a lower grade than 5. 2) As the reducing gas, NH_3 gas, N_2 gas, H
2. A method for producing a vanadium lower oxide thin film according to claim 1, which comprises using one or more mixed gases of _2 gas and SO_2.