JPH0676667B2 - Manufacturing method of vanadium lower oxide thin film - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for forming a thin film of vanadium lower oxide, and mainly relates to the production or surface of temperature sensitive element materials, thermoelectric element materials, switching materials and the like. Used for processing.

[Conventional technology]

Conventionally, ammonium metavanadate (NH ₄ VO ₃ ) or V ₂ O ₅ powder was mixed with NH ₃ gas at 1 to 20 times (vanadium raw material molar ratio) 4
It is known from JP-A-49-47294 that V ₂ O ₃ powder can be obtained by reduction at 50 to 700 ° C. for 1 to 6 hours, but this method cannot form a thin film.

A method of applying a V ₂ O ₅ hydrated gel to an insulating substrate and simply drying it is known from JP-B-57-29502. At this time, conductivity is imparted by the V ^{4 +} ions originally contained in the V ₂ O ₅ hydrated gel, and an antistatic effect is exhibited, but in general, most of the V ₂ O ₅ hydrated gel is conductive. Since it contains non- ^active V 5 ⁺ ions, in order to contain a large amount of V ^{4 +} ions, the temperature control during the production of V ₂ O ₅ hydrated gel must be extremely strictly high, When the temperature is elevated, the amount of V ₂ O ₅ hydrated gel recovered decreases, resulting in high cost. The formation of a film after coating and drying is not described in JP-B-57-29502, and as a result of an additional test, no film is formed until then, and it is necessary to add a film-forming agent separately.

Also, put V ₂ O ₅ and the metal as a reducing agent together in a vacuum vessel,
These subliming, a method of and to VO _2, V ₂ O ₃ produced by reducing retrieve those cooled and solidified are known Te cowpea in JP-A-50-72894 in the gaseous state, the sealing vacuum A container is required, which is troublesome, the productivity is low, and the cost is high.

[Problems to be solved]

This invention is because the method is simple and a vanadium lower oxide film is formed on the surface of a substrate by a reduction treatment at a low temperature.

[Problems to be solved]

This invention melts V ₂ O ₅ and melts it to 100 ℃ -150 ℃
The first step to obtain a V ₂ O ₅ hydrated gel by pouring what is kept at a high temperature into pure water and one kind of water containing 10 to 30% of acetone, and this V ₂ O ₅ water The second step is to dilute the Japanese gel and apply it to the substrate, and in a reducing gas stream at 150 ° C to 700 ° C for 30 minutes to 3 minutes.
Heat for hours to remove the applied V ₂ O ₅ hydrated gel on the substrate.
A method for producing a vanadium lower oxide thin film is characterized by comprising a third step of forming a vanadium lower oxide thin film lower than V ₂ O ₅ .

The method of the present invention will be described more specifically.

a) V ₂ O ₅ is not particularly limited put but for example, V ₂ O ₅ the crucible as a method of obtaining a preparation V ₂ O ₅ hydrated gel of hydrated gel, then melting the same, than the melting temperature
After maintaining a high temperature of 100 to 150 ° C for a uniform molten state, quickly add 10 to 30% of acetone to pure water or water.
V ₂ O ₅ hydrated gel is obtained by pouring into a liquid containing about ₅ %, and this is diluted to a concentration of 10 g / l V ₂ O ₅ prior to use.

b) The substrate to be coated is magnetic product material, glass such as photographic product material, ceramics, synthetic resin plate, etc.
Use a temperature of 70 ° C or higher.

c) As a coating method, brush or roller coating, spraying, electrostatic coating, dipping and the like are included in the coating method of the present invention.

d) The heater used in the method of drying and heating is not particularly limited as long as it can be shielded from the outside air, and a heater capable of adjusting to a desired heating temperature is preferable, and an electric furnace is most convenient.

The heating temperature is not higher than the melting temperature of the substrate.

First, on the surface of the substrate described in the above item b),
The V ₂ O ₅ hydrated gel is applied by the application method described in the item c).

Thus, NH ₃ gas, H ₂ which is usually used as a reducing gas.
Gas, SO ₂ gas, or CO gas is passed through the heating furnace and
_The substrate coated with the ₂ O ₅ hydrated gel is placed in a heating furnace, the temperature in the heating furnace is adjusted to the melting or deformation temperature of the substrate or lower, and the mixture is heated for 30 minutes to 3 hours, and V _{2 on the} surface of the substrate is adjusted. The O ₅ hydrated gel layer is reduced to form a vanadium lower oxide film such as V ₂ O ₃ or V ₂ O ₄ on the substrate surface.

〔effect〕

First, in V ₂ O ₅ hydrogels produced in the first step of the method is amorphous, and becomes a number 100Å ultrafine particles, the V ₂ O
_Since the method of applying pentahydrate gel to the substrate is adopted, it is easy to apply. Especially, since it is in the form of gel, not only glass and ceramic surfaces but also various plastic surfaces can be easily applied. In addition, V ₂ O ₅ is amorphous and has a high activity because it is ultra-fine particles of several hundred liters. The reducing gas to be contacted with it is small, the reduction temperature is relatively low, and the reduction time is short. The degree of freedom in selection is extremely high, and the vanadium lower oxide produced forms a film on the surface of the substrate.

Moreover, since the reduction reaction can be carried out at normal pressure (reacting even under increased pressure or reduced pressure), a large amount of continuous reaction is also possible.

In particular, since it does not depend on V ^{4 +} ions in V ₂ O ₅ hydrated gel at all, there is no particular limitation on the method for producing V ₂ O ₅ hydrated gel,
Since it is possible to select a method with a high yield of V ₂ O ₅ hydrated gel, the cost is low and it is extremely useful.

Experimental Example 1 50 g of V ₂ O ₅ was placed in a porcelain crucible and kept in an electric furnace for 30 minutes at 800 ° C.
(V ₂ mp 690 ° C. in O ₅₎ to keep then poured quickly the molten metal in pure water of 1, to give a V ₂ O ₅ hydrogels, which V ₂
O ₅ concentration diluted to 1%, porcelain plate (50 x 50 mm) as a substrate
The above solution was applied to this surface in an area of 20 × 20 mm so as to have a thickness of 100 μm, and after natural drying, H ₂ was placed in an electric furnace.
After supplying gas at 10 ml / min for 1 hour, after reacting at 570 ° C., the temperature was lowered to room temperature, and the film formed on the substrate surface was mostly a V ₂ O ₃ thin film by X-ray diffraction. I confirmed.

Experimental Example 2 The same substrate as in Experimental Example 1 was coated with V ₂ O ₅ hydrated gel in the same manner, and reacted for 1 hour at 380 ° C. while supplying NH ₃ gas at 10 ml / min to the same electric furnace as described above. However, a VO ₂ thin film was formed on the surface of the substrate.

Experimental Example 3 The same thing as Experimental Examples 1 and ₂ was used with SO ₂ gas as the reducing gas.
After reacting at 240 ° C for 2 hours in a stream of ml / min, V ₆ O ₁₃
A thin film mixed with V ₃ O ₇ was obtained.

Experimental Example 4 (Comparative Experiment) The same thing as Experimental Examples 1 to 3 was reacted at 300 ° C. for 30 minutes in air without using reducing gas, and V ₂ O ₅
Thin film was formed.

Experimental Example 5 (Comparative Experiment) When the same thing as each of the above experimental examples was simply dried in air, no film was formed on the surface, and amorphous V ₂ O ₅ was attached and formed.

Further, using NH ₃ , H ₂ , and SO ₂ as the reducing gas, the relationship between the reducing temperature and the oxides formed on the surface of the substrate is as shown in the following table.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Uchioki 3-27-13 Chikko Shinmachi, Sakai City, Osaka Prefecture Inside the Sakai Seaside Plant, Shinko Chemical Industry Co., Ltd. (56) Reference JP-A-51-147281 (JP, A) JP-A-49-47294 (JP, A)

Claims (2)

[Claims] 1. V ₂ O ₅ is melted, and the melting temperature is 100 ° C. to 150 ° C.
What is kept at ℃ higher temperature is pure water, acetone 10 to 30%
First V ₂ O ₅ is poured into the liquid of one of a degree-containing water
The first step of obtaining a hydrated gel, the second step of diluting the V ₂ O ₅ hydrated gel and applying it to the substrate, and 30 minutes to 3 minutes in a reducing gas stream at 150 ° C to 700 ° C.
Heat for hours to remove the applied V ₂ O ₅ hydrated gel on the substrate.
A method for producing a vanadium lower oxide thin film, comprising a third step of forming a vanadium lower oxide thin film lower than V ₂ O ₅ . 2. NH ₃ gas, CO gas, H ₂ as the reducing gas
The method for producing a vanadium lower oxide thin film according to claim 1, which comprises a method of using one of gas and SO ₂ gas or a mixed gas for maintaining two of these gases.