JPS6172700A - Molybdenum oxide whisker and its production - Google Patents

Abstract

PURPOSE:To produce a molybdenum oxide whisker, easily, by calcining metallic molybdenum powder in an oxygen-containing atmosphere at a specific temperature. CONSTITUTION:Powder of metallic molybdenum is put into a heat-resistant open vessel (e.g. alumina substrate, ceramic crucible, etc.), and calcined at >=400 deg.C in an oxygen-containing atmosphere (e.g. oxygen, air, etc.). The molybdenum oxide whisker can be obtained in a yield of about 10-15% in the form of rods or flakes. The remaining molybdenum oxide powder is reduced to metallic molybdenum by heating in hydrogen atmosphere at 950-1,100 deg.C, and used as a raw material for the production of molybdenum oxide whisker.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention relates to rod-shaped or flake-shaped molybdenum oxide whiskers and a method for producing the same.

"Prior Art and its Problems J Metal oxides can take the form of rods, lines, needles, flakes, etc. and are called whiskers. Metal oxides that form whiskers include Aluminum oxide (Al2O2), zinc oxide (ZnO),
Beryllium oxide (Bed), Magnesium #chloride (M
gO) etc. are known. These whiskers have a special shape and are extremely strong.
Currently used as a filler for plastics,
In addition, various other uses are being considered.

As described above, whiskers made of extrapolated metal oxides are known, but molybdenum oxide (M2O3) has not yet been known to form whiskers, and its properties have not been clarified.

``First aspect of the invention'' An object of the present invention is to provide molybdenum oxide lybdenum, scar, and a method for producing the same, which are expected to be applied to various uses as a new industrial material.

"Structure of the Invention" The molybdenum oxide whisker of the present invention is made of molybdenum oxide and has a rod-like or flake-like shape as a whole.

On the other hand, the method for producing molybdenum oxide whiskers of the present invention is a method in which metal molybdenum powder is fired at a temperature of 400° C. or higher in an oxygen-containing atmosphere.

In addition, the method for producing a further improved molybdenum oxide whisker of the present invention involves firing metal molybdenum powder at a temperature of 400°C or higher in an oxygen-containing atmosphere, collecting the generated molybdenum oxide whiskers, and then removing the remaining molybdenum oxide whiskers. In this method, the powder is thermally reduced to 850 to 1100°C in a hydrogen atmosphere to obtain metal molybdenum powder, and this metal molybdenum powder is used again as a raw material.

Next, the present invention will be explained more specifically.

Store the metal molybdenum powder in a heat-resistant open container (alumina substrate,
(magnetic crucible, quartz container, etc.) and fired in an oxygen-containing atmosphere. Here, the oxygen-containing atmosphere means oxygen or an atmosphere containing oxygen, and may be, for example, oxygen or air.

The firing temperature is preferably the temperature at which the position decreases when the metal molybdenum is oxidized, that is, the sublimation (or /A' emission) temperature of the oxide, and is preferably 400° C. or higher in terms of four bodies. If the firing temperature is less than 400°C, molybdenum oxide whiskers cannot be obtained efficiently. Furthermore, the higher the firing temperature, the larger the shape of the resulting molybdenum oxide whiskers tends to be. The oxidation rate of molybdenum metal, expressed as the rate at which the weight decreases when molybdenum metal is oxidized, is approximately - in 1 hour at 700°C.
10mg/crn', -31hg in 1 hour at 800℃
/crrf. By firing, the metal molybdenum is rapidly oxidized to form rod-shaped or flake-shaped molybdenum oxide whiskers. In this case, the yield of molybdenum oxide whiskers is about 10 to 50%.

The remainder becomes molybdenum oxide powder.

Therefore, in order to further increase the yield of molybdenum oxide whiskers, the molybdenum oxide powder that has not become whiskers is heated to 950 to 1100° C. in a hydrogen atmosphere and reduced to regenerate metal molybdenum. This metal molybdenum is fired again at a temperature of 400° C. or higher in an oxygen atmosphere to produce molybdenum oxide whiskers. By repeating this operation, molybdenum oxide whiskers can be produced in high yield.

"Embodiments of the invention" Example 1 Metallic molybdenum powder (purity 88.9%, particle size 0.5~
1g of Igm) was placed on an alumina substrate, and 400 g of Igm was placed in the air.
Firing was carried out by leaving it at ℃ for 60 minutes. As a result, about 100 mg of molybdenum oxide whiskers with a thickness of 54 m or less and a length of 0.5 cm or less were obtained.

Example 2 Metallic molybdenum powder (purity 88.9%, particle size 0.5~
Lgm) was placed on an alumina substrate and exposed to 600°C in air.
Firing was carried out by leaving it at ℃ for 60 minutes. As a result, about 300 mg of molybdenum oxide whiskers having a thickness of 50 g, an o+ or less, and a length of 2 mm or less were obtained.

Example 3 Metallic molybdenum powder (purity 99.9%, particle size 0.5~
Place 1g of Igm) on an alumina substrate and add 800 g of Igm in the air.
Firing was carried out by leaving it at ℃ for 60 minutes. As a result, a rod shape with a thickness of 70 p-m or less and a length of 5 mm or less, or a width of 3
Approximately 500 pieces of molybdenum oxide whiskers in the form of flakes with a thickness of less than 00 tiles, a thickness of less than 20 cm, and a length of less than 7 cm.
I got mg.

A micrograph of this molybdenum oxide whisker at a magnification of 15 times is shown in FIG.

Example 4 In Examples 1 to 3, the remaining molybdenum oxide powder that did not become whiskers was heated at 950°C in a hydrogen stream at ]000
0℃l05Q℃1+100'C for 60 minutes 11J each
I heating to reduce molybdenum oxide and regenerate metal molybdenum powder. This metallic molybdenum powder was again placed on alumina), E JIv, and fired at 800°C for 60 minutes to obtain molybdenum oxide whiskers similar to those in Example 36. Note that the whiskers obtained in Examples 1 to 4 teeth.

As a result of X-ray diffraction, it was found to be molybdenum oxide whiskers.

"Effects of the Invention" As described above, according to the present invention, molybdenum oxide whiskers can be easily obtained by firing metal molybdenum powder at a temperature of 400° C. or higher in an oxygen-containing atmosphere. Further, after firing, the remaining molybdenum oxide powder is heated in hydrogen to reduce it, and the regenerated metal molybdenum powder is used as a raw material again, thereby further improving the yield of molybdenum oxide whiskers. The molybdenum oxide whiskers thus obtained are rod-shaped or flake-shaped and are expected to be used as various industrial materials.

[Brief explanation of drawings]

FIG. 1 is a 15x W4 microphotograph showing the grain structure of molybdenum oxide whiskers obtained according to the present invention. ji i ””=;

Claims (3)

[Claims] (1) A molybdenum oxide whisker made of molybdenum oxide and characterized by having a rod-like or flake-like shape as a whole. (2) Metallic molybdenum powder was heated to 400% in an oxygen-containing atmosphere.
A method for producing molybdenum oxide whiskers, characterized by firing at a temperature of ℃ or higher. (3) Metallic molybdenum powder was heated to 400% in an oxygen-containing atmosphere.
After firing at a temperature of ℃ or higher and collecting the generated molybdenum oxide whiskers, the remaining molybdenum oxide powder is reduced by heating to 950 to 1100 ℃ in a hydrogen atmosphere to obtain metal molybdenum powder, and this metal molybdenum powder is used again as a raw material. A method for producing molybdenum oxide whiskers, characterized in that the whiskers are used as molybdenum oxide whiskers.