JPH07187630A - Ferromagnetic carbon material and its production - Google Patents

Abstract

PURPOSE:To obtain a ferromagnetic carbon material made of entirely carbonaceous ungraphitized carbide by heating an org. substance or ungraphitized carbide of the org. substance at a certain temp. in the presence of halogen. CONSTITUTION:An org. substance or ungraphitized carbide of the org. substance is heated at 250-800 deg.C in an oxygen-free inert gaseous atmosphere contg. 1-5vol.% halogen or halogen generating agent to obtain the objective ferromagnetic carbon material made of entirely carbonaceous ungraphitized carbide. This material has the advantage of low specific gravity and lightweight and is easy to produce.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ferromagnetic carbon material which does not contain any transition metal element and is composed of 100% carbonaceous material, and a method for producing the same.

[0002]

2. Description of the Related Art Heretofore, simple substances, alloys, oxides, etc. of transition metals such as iron, cobalt and nickel have been used as ferromagnetic materials. These ferromagnetic materials have many merits such as a large magnetic susceptibility, a large coercive force and a remanent magnetization value, but on the other hand, they have some disadvantages. Since (1) is a heavy metal element, it has a large specific gravity and is inconvenient for transportation to outer space.
The reason (2) is that elements other than iron are unevenly distributed on the earth as resources, and there is concern that resources will be depleted in the future. Since (3) is a metal element, it has a high hardness and is unlikely to be a soft material. That (4)
When you no longer need it, you may want to demagnetize and dispose of it, but this requires a lot of energy.

[0003]

A material that overcomes the drawbacks of the conventional ferromagnetic material, in other words, a ferromagnetic material that can be used complementarily to the conventional ferromagnetic material, is as described above (1). It has a small specific gravity, and (2) is rich in resources,
(3) It is a non-metal element, and has properties such as (4) that it can be easily incinerated. A carbon material is one of candidates for such a material. Therefore, the present invention provides
It is an object of the present invention to provide a carbon material having ferromagnetism and a method for producing the same.

[0004]

As a result of intensive studies to solve the above problems, the present inventor has found that ungraphitized carbide having a carbon content of 100% exhibits ferromagnetism, and has completed the present invention. It was That is, according to the present invention, there is provided a ferromagnetic carbon material composed of 100% carbonaceous ungraphitized carbide. Further, according to the present invention, an ungraphitized carbide of an organic substance is heat-treated at a temperature of 250 to 800 ° C. in the presence of halogen or a halogen generating agent to obtain an ungraphitized carbide of 100% carbonaceous. A method of manufacturing a ferromagnetic carbon material is provided. Further, according to the present invention, an organic substance is heat-treated in the presence of halogen or a halogen generator at a temperature of 250 to 800 ° C. to obtain an ungraphitized carbide containing 100% carbonaceous material. A method for manufacturing a carbonaceous material is provided.

In order to obtain a ferromagnetic carbon material in the present invention, as can be seen from FIG. 1, hydrogen atoms contained in ungraphitized carbide are finely removed while avoiding graphitization of the carbide. It is necessary to. Further, as can be seen from FIG. 1, since the electron orbit of the carbon atom has a sp2 type planar structure, when a saturated hydrocarbon type compound is used, the transition from the sp3 type tetrahedral structure to the sp2 type structure is performed. Must happen. Therefore, the carbon atom must provide the so-called "roll over" mobility. Heat treatment is used to provide such motility. In the present invention, in order to avoid graphitization of the resulting carbide and obtain an ungraphitized carbide containing 100% of carbonaceous material containing no hydrogen atom, the carbide or organic substance is added in the presence of halogen or a halogen generating agent, 250-800 ° C, preferably 400-
Heat treatment is performed at a temperature of 600 ° C.

Conventional carbides obtained by heat treatment of organic substances contain hydrogen atoms, but such carbides do not exhibit ferromagnetism. However, when heat treatment is performed in the presence of halogen or a halogen generating agent, the hydrogen atom is more stable in the case where it is bonded to the halogen than in the case where it is bonded to the carbon. Therefore, hydrogen in the carbide reacts with the halogen. It can be removed from the carbide to obtain 100% carbonaceous carbide. Further, by controlling the heat treatment temperature so as not to exceed 800 ° C., graphitization of the carbide can be suppressed, and a carbon atom exhibiting ferromagnetism having SP2-sigma unpaired electrons can be generated.

As a method of obtaining a ferromagnetic carbon material according to the present invention, a method of heat-treating an organic substance to obtain a carbide in advance and then heat-treating the carbide in the presence of halogen or a halogen generating agent can be preferably adopted. However, a method of directly heat-treating an organic substance in the presence of halogen or a halogen generating agent to obtain a ferromagnetic carbon material can also be adopted. It is well known that heat treatment of an organic substance produces a carbide. Although various kinds of organic substances are used, those which are solid at room temperature are preferable because of easy handling. Further, from the viewpoint of giving a high carbide yield, it is preferable to use an organic substance having a high carbon content. Specific examples of organic substances include, for example, various pitches of petroleum and coal series; polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyacrylate,
Organic polymeric substances such as polymethacrylate; pulp powder,
Examples include woody materials such as wood powder. The organic substance may contain oxygen atoms, nitrogen atoms, sulfur atoms, and alkali metal atoms in addition to carbon atoms and hydrogen atoms, but since silicon atoms and metal atoms remain in the carbide, these It is preferable to contain as few atoms as possible, and the content in the carbide is kept at 10% by weight or less, preferably zero%.

Chlorine or bromine is usually used as the halogen, and a substance that produces halogen under heating conditions, such as carbon tetrachloride or various halogenated hydrocarbons, is used as the halogen generating agent. The heating atmosphere may be a halogen or a halogen generating agent atmosphere, or an inert gas (N, CO 2, argon gas, etc.) containing these. In the case of an inert gas atmosphere containing halogen or a halogen generating agent, the content of the halogen or halogen generating agent is 1 to 5 vol%. The oxygen concentration in the atmosphere is 0.1 vol% or less, preferably zero%. The atmospheric pressure may be normal pressure, increased pressure or reduced pressure,
When the organic substance is easily gasified or sublimated, it is preferable to apply pressure.

[0009]

The ferromagnetic carbon material of the present invention has the advantages of low specific gravity and light weight, is easy to manufacture, and can be easily incinerated if necessary.

[0010]

EXAMPLES Next, the present invention will be described in more detail by way of examples. Example 1 Polyvinyl chloride (abbreviated as PVC) (2 g) was taken and placed in a hard glass tube having a large number of through holes in the tube wall shown in FIG. 2 under a reduced pressure of about 1 Pascal from 20 ° C. to 200 ° C. 15 ° C. /
Heat at a heating rate of 5 minutes, and increase the heating rate from 200 ° C to 5 ° C /
Heat to 280 ° C in minutes. Hold at 280 ° C for 60 minutes and then make an emergency order. After cooling and taking out and weighing,
The yield is 17.3% at 0.346 g. Next, the thus-obtained carbide was placed in a glass tube shown in FIG. 2 and placed in a carbon tetrachloride gas stream having a pressure of 1.33 Pascal and a space velocity of 137 m at a temperature rising rate of 35 ° C./min. The temperature is raised to 250 ° C. and further to 400 ° C. at 5 ° C./minute. Four
Hold at 00 ° C for 120 minutes, then quench. The yield is 0.
It is 15.0% with respect to the amount of starting PVC at 3 g. When the magnetic susceptibility of this carbide was measured by the vibration capacitance method, the coercive force was 3.82 mT and the residual magnetization was 1.57 × 10 2 emu / g
Got

Example 2 2 g of PVC was taken, placed in a glass tube shown in FIG. 2 and heated in a carbon tetrachloride stream. The pressure of carbon tetrachloride is 1.33 Pascal and its space velocity is 137 m. 20 from 20 ℃
It is heated to 0 ° C. at a temperature rising rate of 15 ° C./min, and heated from 200 ° C. to 280 ° C. at a rate of 5 ° C./min. 28
Hold at 0 ° C for 60 minutes and then make an emergency order. After cooling, the product is taken out and weighed, and the yield is 0.328 g, which is a yield of 16.4%. The carbide thus obtained was again transferred to the glass tube of FIG. 2 and heat-treated at the same flow rate in the same carbon tetrachloride stream as above. Heat up to 250 ° C at 35 ° C / min, then 5
The temperature is raised to 400 ° C at a rate of ° C / min. Hold at 400 ° C for 120 minutes, then quench. Yield 0.266g, yield 1
It is 3.3%. When the magnetic susceptibility of this carbide was measured, the coercive force was 3.78 mT and the residual magnetization was 3.60 × 10.
emu / g was obtained.

Example 3 The ferromagnetic carbon material prepared in Example 2 was heat treated again in a carbon tetrachloride stream for the purpose of further improving the quality. The heating container used was that shown in FIG. The reprocessing temperature is from 400 ° C to 800 ° C, the pressure of carbon tetrachloride is 1.33 Pa,
The linear velocity is 137 m / min. From 20 ° C to 300 ° C, heating is performed at a heating rate of 20 ° C / min, from 300 ° C to 50 ° C below the final reached temperature, heating is performed at 5 ° C / min, and from that temperature to the final reached temperature The temperature was raised at 1 ° C / min. When the final heating temperature was reached, the temperature was maintained for 100 minutes and then rapidly cooled to room temperature. The yield of the thus obtained reheat-treated ferromagnetic carbon material was about 77 to 90% based on the used primary treatment raw material. The magnetic susceptibility of the carbon material thus reheat-treated was measured, and the obtained coercive force and residual magnetization were plotted against the temperature of the reheat treatment. The results are shown in FIG. FIG. 4 shows a hysteresis curve of magnetic susceptibility obtained from the 500 ° C.-treated product having the largest residual magnetization in FIG. 3.

Example 4 Take 2.0 g of charcoal, grind this to 100 mesh or less, put in a magnetic boat, and under the same conditions as in Example 3 (final ultimate heating temperature 600 ° C.) in a carbon tetrachloride stream. Was heat-treated. The yield was 13%. The magnetic susceptibility of this material was measured, and the coercive force was 0.3 mT and the residual magnetization was 7.0.
× 10 2 emu / g was obtained.

[Brief description of drawings]

FIG. 1 shows a structural formula of a ferromagnetic carbon material molecule.

FIG. 2 shows a hard glass tube for carbonization reaction.

FIG. 3 is a graph showing a change in magnetism of a ferromagnetic carbon material depending on a reheat treatment temperature.

FIG. 4 shows a magnetic susceptibility curve of a 500 ° C. reheat-treated product.

Claims (3)

[Claims] 1. A ferromagnetic carbon material comprising 100% carbonaceous ungraphitized carbide. 2. An ungraphitized carbide of an organic substance is heated at 250 to 800 ° C. in the presence of halogen or a halogen generating agent.
A method for producing a ferromagnetic carbon material, characterized in that the non-graphitized carbide having 100% carbonaceous matter is obtained by heat treatment at the temperature. 3. A ferromagnetic carbonaceous material characterized in that an organic substance is heat-treated in the presence of halogen or a halogen generating agent at a temperature of 250 to 800 ° C. to obtain an ungraphitized carbide containing 100% of carbonaceous matter. Manufacturing method.