JPH0445977B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing materials whose main component is carbon (herein, they are collectively referred to simply as carbon).

[Prior art and its problems] Conventionally, carbon was considered to be conductive carbon such as graphite. Diamond, a single crystal of carbon, is known for its many properties, including hardness and the highest thermal conductivity coefficient of any insulator. This Dunyamond was first synthesized only under ultra-high pressure and ultra-high temperature, and other carbons were poor conductors with graphite-like hardness and brittleness.

However, when this carbon is used using the plasma vapor phase method, it has an insulating property with an optical energy band width of 2.6 to 4.5 eV, and can be formed at temperatures below 650°C, especially at 200 to 400°C. The present invention is based on the discovery that it has the following characteristics.

An object of the present invention is to form fibrous carbon by forming carbon whose main component is crystalline carbon into a fibrous core.

[Means for solving problems]

In order to achieve the above object, the present invention includes means for supplying a reactive gas to a reaction vessel, means for vacuum evacuation of the reactive gas in the vessel, and means for supplying microwave energy to the reactive gas. In a method using a plasma reactor equipped with a plasma reactor, a fibrous core is provided in the reaction vessel maintained under reduced pressure, and a carbide gas having a triple bond or double bond, which is the reactive gas, and hydrogen are combined. Introducing a gas mixture and supplying the microwave energy to the reactive gas to generate a plasma gas phase reaction, and further supplying high frequency energy of 500 W or more to the gas mixture to form the fibrous core,
This is to form carbon whose main component is crystalline carbon.

Fibrous carbon is formed by using fibers made of organic materials such as nylon, tetron, etc., glass, metal, or ceramic for the central core, and forming a cylindrical film of reacted carbon on or on the surface. .

This cylindrical shape is made of fiber or simply carbonized fiber at its center, but its surface is
A coating with a thickness of 30 μ or less and extremely hard, that is, optically has an energy band width of 2.0 eV or more, especially 2.6 to 4.5 eV, and has a hardness similar to that of a diamond, is provided in a cylindrical shape. It has strong properties such as strength.

Hydrocarbons having triple bonds or double bonds, such as acetylene or ethylene, are mainly used as the reactive gas.

The present invention will be described below with reference to the drawings.

〔Example〕

FIG. 1 shows an outline of a plasma CVD (vapor phase method) apparatus used in the present invention.

In the drawing, a reactor 1 is provided with electromagnetic energy 2 by means of induction or capacitance. Furthermore, the acetylene 8, which is a hydrocarbon, passes through a flow meter 5 and reaches an excitation chamber. This reactive gas is composed of hydrogen, diluted by carrier gas 7, and both activated or decomposed by applying microwave magnetic energy 3 of 2.45 GHz. This activated or decomposed reactive gas is further promoted to bond by electromagnetic energy 2 of high frequency, typically 13.56 MHz, and is formed in the form of a film on the surface of the heated fibrous core 12.
This core is passed from roll 10 to roll 9, during which a carbon film is formed on the surface, and in order to make it even thicker, it is rolled again from roll 9 to roll 10.
Repeat this to increase the thickness. In addition, this fiber is not one, but 100 to 10, ^{and four} fibers, each with 1 to
They were placed in the reaction space with a spacing of 10 mm to increase the initial surface area and improve the carbon absorption efficiency.

This reactive gas and the core fiber are heated to 150 to 160°C by heaters 14 and 15 to accelerate the reaction. After the reaction, unnecessary substances reach the rotary pump 11 via the exhaust 11. This is during the reaction
It is critical to provide an atmosphere of 0.001 to 10 torr, typically 0.1 to 0.5 torr, to the reactive gas.

Microwaves were introduced into the excitation chamber 4 at a power of 50 to 5000 W, typically 200 to 500 W, and were effective for cleaving hydrogen in C--H bonds.

Furthermore, it is important to provide 100 to 300 W of electromagnetic energy at a frequency of 13.56 MHz to create a large optical bandwidth (called Eg) in order to give kinetic energy to the activated carbon and cause them to collide and bond with each other. It was hot.

However, in the present invention, the output of this electromagnetic energy is set to 500 W or more, and the structure is made to have crystallinity with a size of 5 to 200 Å.

The formed carbon had an Eg of 0.1 to 1.5 eV when the reactive gas was simply thermally decomposed, and its hardness was not sufficient in that case, but when electromagnetic energy of 3.2 was further applied, the Eg was 2.6 to 4.5 eV. Typically 3.0
~3.5eV, and in this case, the Bitkers hardness is also
It had an excellent value of 4500 to 5500 Kg/mm ² or more. It also had a high thermal conductivity of 5.0 (W/cmdeg).

Also, when making carbon fibers, the thickness of the core can be changed arbitrarily, but in reality, the diameter can be changed.
300μm (0.3mm) or less, typically 10
30μm or less, e.g. 1~100μm fiber surface
Carbon with a thickness of 10 μm (in this case, the core is also carbon as a component, but its optical band width Eg is less than 2 eV on average, so only the surface thickness is considered) is just bamboo. As a result, we were able to create a fibrous structure that is extremely light and has strong binding strength.

Of course, the core of this fibrous structure may be directly carbonized in plasma, and the highly hard carbon of the present invention may be formed on the surface to a thickness of 0.1 to 5 μm.

Such carbon fibers were mixed into general plastics to form composites. Since such materials are light in weight, they are used in aircraft etc.
In addition, if it has 3.5 eV or more, it can be used as tempered glass or a part of it.
Its applications are immeasurable.

In the present invention, the mainly formed carbon exhibited an amorphous structure when electromagnetic energy was weakly applied. However, when the electromagnetic energy output was increased to 500 W or more, a crystalline structure with a size of 5 to 200 Å was obtained. This crystallinity resulted in even stronger hardness.

In the above, carbon is described as the main component, but it also contains hydrogen from 0.01 to 10 mol% (atomic %), and further contains valence, valence, or valence impurities in an amount of 3 mol% (atomic %) or less. It may be included to provide P or N type conductivity while having an average voltage of 2.6 to 4.5 eV.

Furthermore, the core in the present invention is made of organic fiber. However, if this core is made of glass and its surface is coated with carbon, the refractive index of this carbon is 2.3 to 2.6, so it is possible to reduce the loss of optical signals on the surface of SiO ₂ fiber for optical communication. It is extremely effective. In this case, the cylindrical coating is made of carbon, which is an inexpensive material that has high strength, especially tensile strength, as a fiber communication cable, so we believe that its industrial value is extremely large.

Furthermore, metals such as copper or ceramics may be used as the core for providing this fibrous shape, and in the case of thin metal wires, its processing strength can be improved, and it has excellent electrical insulation properties, so it has heat resistance. Ideal as a conductor.

[Effects of the present invention]

A method using a plasma reactor comprising means for supplying a reactive gas to a reaction vessel, means for vacuum evacuation of the reactive gas in the vessel, and means for supplying microwave energy to the reactive gas, In the reaction vessel maintained under reduced pressure,
A core having a fibrous shape is provided, a mixed gas of hydrogen and a carbide gas having a triple bond or double bond as the reactive gas is introduced, and the microwave energy is supplied to the reactive gas to generate a plasma gas phase. By causing a reaction and further supplying high frequency energy of 500 W or more to the mixed gas to form carbon mainly composed of crystalline carbon in the fibrous core, crystalline carbon is produced. It becomes possible to form fibrous carbon by forming a core having a fibrous shape from carbon containing as a main component.

[Brief explanation of drawings]

FIG. 1 shows an outline of an apparatus for producing carbon according to the present invention.

Claims (1)

[Scope of Claims] 1. A plasma comprising means for supplying a reactive gas to a reaction vessel, means for vacuum evacuation of the reactive gas in the vessel, and means for supplying microwave energy to the reactive gas. In a method using a reaction device, a fibrous core is provided in the reaction vessel maintained under reduced pressure, and a mixed gas of hydrogen and a carbide gas having a triple bond or double bond, which is the reactive gas, is supplied. and supplying the microwave energy to the reactive gas to generate a plasma gas phase reaction, and further supplying high frequency energy of 500 W or more to the mixed gas to impart crystallinity to the fibrous core. A method for producing fibrous carbon, characterized by forming carbon whose main component is carbon. 2. The method for producing fibrous carbon according to claim 1, wherein the fibrous core is an organic material, glass, metal, or ceramic.