JPH0755859B2 - Carbonaceous inorganic material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a carbonaceous inorganic material having excellent mechanical strength, heat resistance, and abrasion resistance.

(Prior art and its problems) Conventionally, carbon materials have been characterized by high temperature characteristics in a non-oxidizing atmosphere,
It has a low coefficient of thermal expansion, chemical resistance, weather resistance, radiation resistance, lubricity, and easy control of electrical and thermal conductivity, so it is used as a high-temperature structural material, friction material, etc. .

However, since carbon materials have low oxidation resistance, they cannot be used at high temperatures in an oxidizing atmosphere. Further, although it has excellent lubricity, its surface hardness is low, so that its wear resistance is not always sufficient.

In order to improve these drawbacks, a method of forming a coating layer of ceramic or the like on the surface of the carbon material by a gas phase reaction method or the like has been devised. However, this method has a drawback that the above-mentioned drawbacks cannot be sufficiently overcome because the coating layer is thin and easily peeled off, and the cost is high because a special device is required.

Further, in JP-A-60-195076 and JP-A-60-251175, the above-mentioned drawbacks are improved by impregnating a carbonaceous molded body with molten silicon and causing a reaction to generate silicon carbide on the surface and inside. A method is disclosed. However, since the carbon material obtained by this method has metallic silicon remaining in the molded body, the high temperature characteristics such as creep deformation at a high temperature are significantly deteriorated, and the mechanical characteristics are not necessarily excellent.

(Means for Solving the Problem) An object of the present invention is to provide a novel carbonaceous inorganic material that solves the above problems.

Another object of the present invention is to provide an oxidation resistant carbonaceous inorganic material which is less deteriorated in a high temperature oxidizing atmosphere.

Another object of the present invention is to provide a carbonaceous inorganic material having excellent wear resistance.

Another object of the present invention is to provide a carbonaceous inorganic material that can be manufactured at a low temperature.

The carbonaceous inorganic material of the present invention is an inorganic material obtained from a silicon-containing polycyclic aromatic polymer, and its constituent components are: i) a polycyclic aromatic compound in a mesophase state which constitutes the polymer. Crystalline carbon, or crystalline carbon and amorphous carbon, ii) crystalline carbon in an unoriented state and / or amorphous carbon derived from an optically isotropic polycyclic aromatic compound constituting the polymer Carbon, and iii) an amorphous phase consisting essentially of Si, C and O, and / or
Alternatively, it is an aggregate composed of crystalline ultrafine particles substantially composed of β-SiC having a particle size of 500 Å or less and amorphous SiO _x (0 <x ≦ 2), and the proportion of constituent elements is Si; 70% by weight, C; 20-60% by weight and O; 0.5-10% by weight Si-CO material.

All "parts" in the following description are parts by weight, and "%"
Is "% by weight".

The carbonaceous inorganic material of the present invention comprises the above constituent components i), ii) and iii), and is substantially composed of Si; 0.5 to 50%, C; 40 to 97% and O; 0.1 to 10%. Has been done.

The crystalline carbon that is a constituent component of this carbonaceous inorganic material is 500
In a high resolution electron microscope with a crystallite size of Å or less and a resolution of 1.5Å, it was oriented in the fiber axis direction.3.
It is an ultrafine graphite crystal in which a fine lattice image corresponding to the 2Å (002) plane can be observed.

The ratio of constituent iii) to the total 100 parts of constituents i) and ii) in this carbonaceous inorganic material is 0.5 to 1900 parts, and the ratio of constituents i) and ii) is 1: 0.02 to 4. .

Component ii for 100 parts of the sum of components i) and ii)
When the ratio of i) is less than 0.5, it is almost the same as that of a carbon material, and it cannot be expected that the oxidation resistance is improved in wear resistance. When the ratio exceeds 1900 parts, the molding is made almost entirely of silicon carbide. It does not become a carbonaceous material that has the same high temperature characteristics and excellent lubricity as the body.

In the carbonaceous inorganic material of the present invention, fine crystals having a small layer interval are effectively generated, and silicon atoms are distributed very uniformly so as to surround the fine crystals.

The carbonaceous inorganic material of the present invention is mainly composed of: i) a bond unit (Si—CH ₂ ), or a bond unit (Si—CH ₂ ) and a bond unit (Si—Si), and a silicon atom is a hydrogen atom or a lower alkyl group. Has a side chain group selected from the group consisting of a phenyl group and a silyl group, and has a bond unit (Si-CH ₂ )
Of the organic silicon polymer having a ratio of the total number of 1 to the total number of bonding units (Si-Si) in the range of 1: 0 to 20 is at least part of the silicon atom of the petroleum-based or coal-based pitch or its heat-treated aromatic product. Random copolymers bound to a group ring via a silicon-carbon linking group, and ii) polycycles composed of a mesophase state or both mesophase and optically isotropic phase obtained by heat-treating a petroleum-based or coal-based pitch Aromatic compounds (hereinafter, both may be collectively referred to as “mesophase polycyclic aromatic polymer”) are heated and / or melted at a temperature in the range of 200 to 500 ° C. to contain silicon. The first step of obtaining a polycyclic aromatic polymer, the silicon-containing polycyclic aromatic polymer, or a mixed powder of the silicon-containing polycyclic aromatic polymer and a fine powder of the calcined product thereof is subjected to a mold press, isotropic static Use ordinary methods such as hydraulic press and hot press Second step of molding, after subjecting the above-mentioned molded body to infusibilization treatment if necessary, it is baked at a temperature of 800 to 3000 ° C. in a vacuum or an inert gas,
Third step of mineralizing, the pores of the carbonaceous inorganic material obtained by the above steps are impregnated with a melt or solution of a silicon-containing polycyclic aromatic polymer as necessary, followed by firing, and the treatment of mineralization is repeated. It is provided by the manufacturing method comprising the fourth step of increasing the density by carrying out.

It is also possible to manufacture the above second to fourth steps as one step by high temperature hot pressing or the like.

Each of the above steps will be specifically described.

First step: The organosilicon polymer, which is one of the starting materials, can be synthesized by a known method. For example, polymethylsilane obtained by the reaction of dimethyldichlorosilane and sodium metal is added in an inert gas at 400 It is obtained by heating to ℃ or more.

The organosilicon polymer, binding unit (Si-CH _2), or binding units (Si-Si) and mainly consists binding units (Si-CH _2), the total number pairing unit of coupling units (Si-CH ₂₎ (Si-S
The ratio of the total number of i) is in the range of 1: 0 to 20.

The weight average molecular weight (M _w ) of the organosilicon polymer is generally 300 to 1000, and the M _w of 400 to 800 is a random copolymer which is an intermediate raw material for obtaining an excellent carbonaceous inorganic material. Especially preferred for preparing coalesced i).

Another starting material, a polycyclic aromatic compound, is a pitch obtained from petroleum and / or coal, particularly a heavy oil obtained by fluid catalytic cracking of petroleum, and obtained by distilling the heavy oil. It is a distillate component or residual oil and a pitch obtained by heat-treating them.

The pitch contains 5 to 98% of insoluble components in organic solvents such as benzene, toluene, xylene, and tetrahydrofuran.
It is preferable that the content is 5% by weight, and when a pitch of less than 5% by weight is used as a raw material, the residual rate at the time of mineralization of the molded product is low, and voids are likely to remain, and it is difficult to crystallize. No carbonaceous inorganic material can be obtained and also 98% by weight
When a larger amount of pitch is used as a raw material, insoluble and infusible caulks are likely to be formed, which is disadvantageous in molding.

The weight average molecular weight (M _w ) of this pitch is 300 to 3000.
And the melting point is 70 to 200 ° C.

The weight average molecular weight is a value determined as follows. That is, if the pitch does not contain the organic solvent insoluble matter for gel permeation chromatograph (GPC) measurement such as benzene, toluene, xylene, tetrahydrofuran, chloroform and dichlorobenzene, the GPC measurement is performed as it is,
When the pitch contains the above-mentioned organic solvent-insoluble matter, hydrogenation treatment is performed under mild conditions to change the above-mentioned organic solvent-insoluble matter into the above-mentioned organic solvent-soluble component, and then perform GPC measurement. (The weight average molecular weight of the polymer containing the organic solvent insoluble matter is a value obtained by performing the same treatment as above).

The random copolymer i) is obtained by adding the above-mentioned pitch to the organosilicon polymer and preferably in an inert gas at 250 to 500 ° C.
It is prepared by reacting by heating at a temperature in the range.

The usage ratio of pitch is 10 to 1 per 100 parts of the organosilicon polymer.
It is preferably 900 parts.

If the use ratio of the pitch is excessively small, the silicon carbide component in the obtained carbonaceous inorganic material will be large, and the lubricity of carbon and the high temperature characteristics in a non-oxidizing atmosphere will be impaired. When it is excessively large, the amount of silicon carbide component is reduced, and the oxidation resistance and wear resistance of the resulting carbonaceous inorganic material deteriorate.

If the reaction temperature of the above reaction is excessively low, the bond between the silicon atom and the aromatic carbon becomes difficult to form, and if the reaction temperature is excessively high, the generated random copolymer is severely decomposed and increased in molecular weight, which is not preferable. .

The mesophase polycyclic aromatic compound ii) can be prepared, for example, by heating petroleum-based or coal-based pitch to 300 to 500 ° C. in an inert gas and polycondensing while removing the produced soft fraction. it can.

If the polycondensation reaction temperature is too low, the condensed ring will not grow sufficiently, and if the temperature is too high, an insoluble and infusible product will be produced by coking.

The mesophase polycyclic aromatic compound ii) has a melting point of 200-4.
It is in the range of 00 ° C and has a weight average molecular weight of 200 to 10,000
Is.

Among the mesophase polycyclic aromatic compounds ii), 20 to 10
Mechanical properties of carbonaceous inorganic materials are those having 0% optical anisotropy and containing 2 to 60% quinoline insoluble matter and 30 to 100% insoluble matter to benzene, toluene, xylene or tetrahydrofuran. Is particularly preferable for improving

In the first step, the random copolymer i) and the mesophase polycyclic aromatic compound ii) are heated and melted and / or reacted at a temperature in the range of 200 to 500 ° C. to prepare a silicon-containing polycyclic aromatic polymer. .

The use ratio of the mesophase polycyclic aromatic compound ii) is preferably 5 to 1900 parts per 100 parts of the random copolymer i), and if it is less than 5 parts, the mesophase content in the product will be insufficient, resulting in high temperature characteristics. If an excellent carbonaceous inorganic material cannot be obtained, and if it is more than 1900 parts, a carbonaceous inorganic material excellent in oxidation resistance and abrasion resistance cannot be obtained due to lack of a silicon component.

The weight average molecular weight of the silicon-containing polycyclic aromatic polymer is 20
It has a melting point of 200 to 400 ° C. at 0 to 11000.

Second step: The silicon-containing polycyclic aromatic polymer obtained in the first step, or the mixed powder of the silicon-containing polycyclic aromatic polymer obtained in the first step and its calcined fine powder is pulverized, The carbon material can be molded using the above-mentioned carbon material molding method. The calcination is 80
It can be carried out at a temperature in the range of 0 to 1300 ° C.

The molding method can be arbitrarily selected from the usual carbon material molding methods in consideration of the shape, size, application, and production characteristics of the molded body. In order to manufacture the polymer with good performance, a dry mold pressing method is used. To obtain a molded article having a slightly complicated shape, an isotropic hydrostatic pressure molding method (rubber press molding method) is used to melt and mold the polymer. Examples thereof include a hot press molding method, an injection molding method and an extrusion molding method.

Further, when the mixture of the polymer and the calcined product thereof is molded, the use ratio of the polymer and the calcined product thereof can be appropriately determined in consideration of the shape, application, cost and the like of the molded product.

Third step: The above-mentioned molded body is subjected to infusibilization treatment if necessary.

A typical infusibilizing method is a method of heating the molded body in an oxidizing atmosphere. The temperature of infusibilization is preferably 50 to 400
The temperature is in the range of ° C. If the infusibilization temperature is too low, no polymer sticking occurs, and if this temperature is too high, the polymer burns.

The purpose of the infusibilization is to make the polymer constituting the molded body into a state of infusible and infusible with a three-dimensional structure so that the molded body is not melted at the time of mineralization in the next step and the molded body shape is maintained. Examples of the gas forming the oxidizing atmosphere at the time of infusibilization include air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, and mixed gas thereof.

As another infusibilizing method other than the above, a method of infusibilizing by γ-ray irradiation or electron beam irradiation while heating the molded body in an oxidizing atmosphere or a non-oxidizing atmosphere at low temperature as necessary is also adopted. be able to.

The purpose of irradiating with the γ ray or electron beam is to prevent the matrix from melting and losing the shape of the molded body by further polymerizing the polymer constituting the molded body.

The appropriate irradiation dose of gamma rays or electron beams is 10 ⁶ to 10 ¹⁰ rads.

Irradiation can be performed in a vacuum, an inert gas atmosphere, or an oxidizing gas atmosphere such as air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, or a mixed gas thereof.

The infusibilization by irradiation can be performed at room temperature, and if necessary, the infusibilization can be achieved by heating while heating in the temperature range of 50 to 200 ° C.

The infusibilized molded body can be vacuumed or in an inert gas.
It is mineralized by firing at a temperature in the range of 800-3000 ° C.

In the heating process, mineralization becomes severe from about 700 ℃,
It is estimated that mineralization is almost completed at about 800 ° C. Therefore, the firing is preferably performed at a temperature of 800 ° C. or higher. Moreover, since an expensive apparatus is required to obtain a temperature higher than 3000 ° C., firing at a temperature higher than 3000 ° C. is impractical in terms of cost.

The infusibilizing step can be omitted by extremely slowing the temperature rise rate of the mineralization in this step, using a shape-retaining jig, a shape-retaining means such as a powder head, or the like. Further, in the molding of the second step, the third step itself can be omitted by using the high temperature hot pressing method.

Fourth step: If necessary, the carbonaceous inorganic material obtained in the third step is impregnated with the melt, solution or slurry of the above-mentioned silicon-containing polycyclic aromatic polymer, and if necessary, rendered infusible and fired to be mineralized. This makes it possible to increase the density and strength of the carbonaceous inorganic material.

The impregnation may be performed by using a melt, a solution or a slurry of a silicon-containing polycyclic aromatic polymer, but in order to permeate fine open pores, a solution of the polymer in the carbonaceous inorganic material is used. Alternatively, after impregnating the slurry, the temperature is increased while promoting the permeation into the fine pores under reduced pressure while distilling the solvent, and 10 to 500 kg / cm 3.
By pressurizing to ² , the pores are filled with the melt of the polymer.

The carbonaceous material impregnated with the above silicon-containing polycyclic aromatic polymer can be made infusible, calcined, and made inorganic in the same manner as in the third step. By repeating this operation 2 to 10 times, a high-density, high-strength carbonaceous inorganic material can be obtained.

The presence state of Si, C, and O in the constituent component iii) can be controlled by the mineralization temperature in the third step and the fourth step.

When it is desired to obtain an amorphous material consisting essentially of Si, C and O, the mineralization temperature is preferably 800 to 1000 ° C. When it is desired to obtain substantially β-SiC and amorphous SiO _x (where 0 <x ≦ 2), a temperature of 1700 ° C. or higher is suitable.

Further, when a mixed system of each aggregate is desired, it can be appropriately selected from the above intermediate temperature.

Further, the amount of oxygen in the carbonaceous composite material of the present invention can be controlled by the infusibilizing conditions in the third step and the fourth step, for example.

(Effects of the Invention) The carbonaceous inorganic material of the present invention contains a silicon carbide component which is very uniformly dispersed and integrated in carbon. The presence of this component promotes the microcrystallization of carbon at low temperatures, suppresses the consumption due to the oxidation of carbon, and improves the hardness.

Therefore, this carbonaceous inorganic material is excellent in mechanical properties, oxidation resistance, and wear resistance, and is excellent as various brakes and heat resistant structural materials.

(Example) The present invention will be described below with reference to Examples.

Reference Example 1 (Manufacturing Method of Polymer I) 2.5 xylene and 400 g of anhydrous sodium were put into a three-necked flask of No. 5, heated to the boiling point of xylene under a nitrogen gas stream, and dimethyldichlorosilane 1 was added dropwise over 1 hour. After completion of the dropping, the mixture was heated under reflux for 10 hours to form a precipitate. The precipitate was filtered, washed with methanol and then with water to obtain 420 g of white powdery polydimethylsilane.

400 g of this polydimethylsilane, a gas introduction tube, a stirrer,
A three-necked flask equipped with a condenser and a distilling tube was charged into a three-necked flask, and heat-treated at 420 ° C under a nitrogen stream of 50 ml / min with stirring, and 350 g of a colorless transparent slightly viscous liquid was put in a distilling receiver. Got

The number average molecular weight of this liquid was 470 as measured by the vapor pressure osmosis method.

The infrared absorption spectrum of this substance was measured and found to be 65
Absorption of Si-CH ₃ of 0～900Cm ^-1 and 1250 cm ^-1, Si in 2100 cm ^-1
Absorption of -H, Si-CH ₂ -Si absorption of the of 1020 cm ^-1 and near 1355 cm ^-1, absorption of CH was observed at 2900 cm ^-1 and 2950 cm ^-1,
Further, when the far-infrared absorption spectrum of this substance was measured, absorption of Si-Si was observed at 380 cm ^-1 , and thus the obtained liquid substance was mainly composed of (Si-CH ₂ ) bond units and (Si-Si). It was found to be an organosilicon polymer having a bonding unit and having a hydrogen atom and a methyl group in the side chain of silicon.

From the results of nuclear magnetic resonance analysis and infrared absorption analysis, this organosilicon polymer shows that the total number of (Si—CH ₂ ) bond units is
It was confirmed that the polymer had a ratio of the total number of -Si) bond units of approximately 1: 3.

300 g of the above organosilicon polymer was treated with ethanol to remove low molecular weight substances, and 40 g of a polymer having a number average molecular weight of 1200 was obtained.

Measurement of the infrared absorption spectrum of this material, the absorption peak similar to that described above was observed, the material consists predominantly (Si-CH ₂₎ coupling units and (Si-Si) bond unit, hydrogen on the side chain of the silicon It was found to be an organosilicon polymer having atoms and methyl groups.

From the results of nuclear magnetic resonance analysis and infrared absorption analysis, this organosilicon polymer shows that the total number of (Si—CH ₂ ) bond units is
It was confirmed that the polymer had a ratio of the total number of -Si) bond units of about 7: 1.

On the other hand, among petroleum fractions, high boiling point substances above light oil are
Fluid catalytic cracking / rectification was carried out at a temperature of 500 ° C. in the presence of an alumina cracking catalyst to obtain a residue from the bottom of the column. Hereinafter, this residue is referred to as FCC slurry oil.

As a result of elemental analysis, the FCC slurry oil had an atomic ratio of carbon atoms to hydrogen atoms (C / H) of 0.75 and an aromatic carbon ratio of 0.55 by nuclear magnetic resonance analysis.

100 g of the above FCC slurry oil was heated to 420 ° C. under a nitrogen gas stream, the distillate at the same temperature was distilled off, and the residue was filtered while hot at 150 ° C. to remove infusible parts at the same temperature and A minute removal pitch of 57 g was obtained.

The light content removal pitch contained 60% xylene insoluble matter.

25 g of the previously synthesized organosilicon polymer and 20 ml of xylene were added to 57 g of the light content removal hitch, the temperature was raised with stirring, the xylene was distilled off, and the mixture was reacted at 400 ° C. for 6 hours to obtain 43 g of a random copolymer. .

As a result of infrared absorption spectrum measurement, this reaction product was found to have Si-H bonds (IR: 2100 cm ^-1 ) present in the organosilicon polymer.
And the formation of a new Si-C (carbon of benzene ring) bond (IR: 1135cm ^-1 ) was observed, so that some of the silicon atoms of the organosilicon polymer were directly bonded to the polycyclic aromatic ring. It was found to be a random copolymer having a portion. In addition, this copolymer did not contain a xylene-insoluble portion, had a weight average molecular weight of 1400 and a melting point of 265 ° C.

This was heated, melted, and allowed to stand at 300 ° C., and 40 g of the remaining portion obtained by removing the light portion due to the difference in specific gravity was obtained. This is called a polymer (a).

In parallel with this, 400 g of FCC slurry oil was heated to 450 ° C. under a nitrogen gas stream, the distillate at the same temperature was distilled off, and the residue was filtered while hot at 200 ° C. The portion was removed to obtain 180 g of a light material removal pitch. 180 g of the obtained light content removing pitch was subjected to polycondensation at 400 ° C. for 8 hours in a nitrogen stream while removing the light content produced by the reaction to obtain a heat treatment pitch of 80.3 g.

This heat treatment pitch has a melting point of 310 ° C, xylene insoluble content of 97%,
It contained 20% quinoline-insoluble matter, and the mesophase pitch was 95% with the optical anisotropy of the polished surface observed by a polarizing microscope.

This was again heated and melted at 350 ° C. and allowed to stand, and the light fraction was separated and removed due to the difference in specific gravity, to obtain 80 g of the rest.

This is mixed with 40 g of polymer (a) and the mixture is mixed in a nitrogen atmosphere for 3
The mixture was melted and heated at 50 ° C. for 1 hour to obtain a silicon-containing polycyclic aromatic polymer in a uniform state. This polymer has a melting point of 290 ° C.
It contained 70% xylene-insoluble matter.

Reference Example 2 (Manufacturing Method of Polymer II) 50 g of the organosilicon polymer obtained in Reference Example 1 was used for removing light components 5
0 g was added, and the mixture was reacted at 420 ° C. for 4 hours to obtain 48 g of a random copolymer.

In parallel with this, the light content removal pitch was reacted at 430 ° C. for 4 hours to obtain a mesophase pitch.

The same weight of the random copolymer and mesophase pitch were mixed and melted in the same manner as in Reference Example 1 to obtain a silicon-containing polycyclic aromatic polymer in a uniform state.

Example 1 The polymer I powder obtained in Reference Example 1 was heated at 800 ° C. in a nitrogen stream.
The temperature was raised to 1, a calcined body was prepared, and this was finely pulverized to obtain a calcined body powder. Granulated powder obtained by adding an equal weight of the powder of Polymer I to the calcined powder and wet-mixing the mixture at 350 ° C. and 100 kg / cm ²
Hot pressing was performed to obtain a disk-shaped molded body having a diameter of 7 cm. This molded body was embedded in a carbon powder powder head and held in shape,
After raising the temperature to 800 ° C at a rate of 5 ° C / h in a nitrogen stream,
The temperature was raised to 300 ° C to make it inorganic. The bulk density of the obtained carbonaceous inorganic material was 1.50 g / cm ³ .

This carbonaceous inorganic material was dipped in a 50% xylene slurry of Polymer I, heated to 350 ° C while distilling off xylene under reduced pressure, and then pressure-impregnated to 100 kg / cm ² , followed by 5 ° C / in air.
The temperature was raised to 300 ° C. at a rate of h to infusibilize it, and then it was mineralized at 1300 ° C. This operation of impregnation and mineralization was repeated three more times to obtain a material having a bulk density of 1.95 g / cm ³ . The bending strength of this material is 2
It was kg / mm ² . Furthermore, when this carbonaceous inorganic material was baked at 2500 ° C. in argon, the bulk density was improved to 1.99 g / cm ³ and the bending strength was improved to 24 kg / mm ² . Also, the bending strength at 1500 ° C. in nitrogen was 25 kg / mm ² .

Example 2 Using Polymer I, 30% of the powder of Polymer II obtained in Reference Example 2 was added to 70% of the calcined powder obtained in the same manner as in Example 1,
Molded and mineralized in the same manner as in Example 1 to have a bulk density of 1.67 g / cm.
³ carbonaceous inorganic materials were obtained.

In the same manner as in Example 1, this material was impregnated with a 50% xylene slurry of Polymer II to be mineralized, and this impregnation and mineralization were repeated 3 times to obtain a carbonaceous inorganic material having a bulk density of 2.01 g / cm ³ . The bending strength of this material was 23 kg / mm ² , and even after this material was kept in air at 600 ° C. for 24 hours, weight reduction and strength reduction were not observed.

Comparative Example 1 20% of mesophase pitch, which is an intermediate product of Reference Example 1, was added to 80% of artificial graphite powder having a bulk density of 0.15 g / cm ³ under no load, and molded in the same manner as in Example 1 to form an inorganic material. To obtain a carbon material having a bulk density of 1.66 g / cm ³ .

This carbon material was impregnated with mesophase pitch and mineralized in the same manner as in Example 1 four times to obtain a carbon material having a bulk density of 1.92 g / cm ² .

The bending strength of this carbon material was 5.0 kg / mm ² , and when this carbon material was kept in air at 600 ° C. for 24 hours, a 20% weight loss was observed and it became porous.

Comparative Example 2 The carbon material having a bulk density of 1.66 g / cm ³ obtained in Comparative Example 1 was sprinkled with metallic silicon powder, melt-impregnated at 1500 ° C., and reaction-sintered to obtain a carbon-silicon carbide composite material. The bending strength of the obtained material is 8.
Although it was improved to ² kg / mm ² , when bending strength was measured at 1500 ° C in nitrogen, deformation occurred due to melting of unreacted silicon.
The bending strength dropped to 3.0 kg / mm ² .

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaki Shibuya 5 1978, Kozugushi, Ube City, Yamaguchi Prefecture 5 Ube Kosan Co., Ltd.

Claims (1)

[Claims] 1. An inorganic material obtained from a silicon-containing polycyclic aromatic polymer, the constituent components of which are: i) crystalline carbon derived from a polycyclic aromatic compound in a mesophase state which constitutes the polymer. Or crystalline carbon and amorphous carbon, ii) non-oriented crystalline carbon and / or amorphous carbon derived from the optically isotropic polycyclic aromatic compound constituting the polymer, and iii) an amorphous phase consisting essentially of Si, C and O, and / or
Alternatively, it is an aggregate composed of crystalline ultrafine particles substantially composed of β-SiC having a particle size of 500 Å or less and amorphous SiO _x (0 <x ≦ 2), and the proportion of constituent elements is Si; A carbonaceous inorganic material comprising a Si—C—O material in an amount of 70% by weight, C: 20 to 60% by weight, and O: 0.5 to 10% by weight.