JPH02217358A - Carbonaceous inorganic material - Google Patents

Abstract

PURPOSE:To reduce deterioration of title material under high-temperature oxidizing atmosphere and improve abrasion resistance by blending a specific crystalline carbon (and amorphous carbon) with a crystalline carbon kept in non- oriented state and/or amorphous carbon and Si-C-O substance. CONSTITUTION:The powder of (C) a silicon-containing polycyclic aromatic polymer obtained by heating (A) a random copolymer obtained by combining an organosilicone polymer consisting of Si-CH2 unit or Si-CH2 unit and Si-Si unit and having side chain with a petroleum based or coal based pitch and (B) mesophase polycyclic aromatic polymer is molded and burned at 800-3000 deg.C in vacuum or inert gas and as necessary melt or solution of the component C is repeatedly impregnated and burned to provide the title material consisting of a crystalline carbon (and amorphous carbon) led from a polycyclic aromatic compound kept in meriphase state and constituting the component C and crystalline carbon kept in a nonoriented state and led from optically isotropic polycyclic aromatic compound constituting the component C and/or amorphous carbon and Si-C-O substance consisting of an amorphous material composed of Si, C and O and/or crystalline ultrafine granules composed of beta-SiC and amorphous SiOx (0<X<=2).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a carbonaceous inorganic material having excellent mechanical strength, heat resistance, and wear resistance.

(Conventional technology and its problems) Carbon materials have traditionally had high-temperature properties in a non-oxidizing atmosphere,
It has a low coefficient of thermal expansion, excellent chemical resistance, weather resistance, radiation resistance, and lubricity, as well as easy control of electrical conductivity and thermal conductivity, so it is used as a high-temperature structural material, friction material, etc. .

However, carbon materials have low oxidation resistance and cannot be used at high temperatures in an oxidizing atmosphere. Furthermore, although it has excellent lubricity, its wear resistance is not always sufficient because of its low surface hardness.

In order to improve these drawbacks, methods have been devised in which a film layer of ceramic or the like is formed on the surface of a carbon material by a gas phase reaction method or the like. However, this method cannot sufficiently overcome the above drawbacks because the film layer is thin and easily peeled off, and also has the drawback that special equipment is required, resulting in high costs.

Furthermore, JP-A-60-195076, JP-A-60
Japanese Patent No. 251175 discloses a method for improving the above drawbacks by impregnating and reacting molten silicon into a carbonaceous molded body to generate silicon carbide on the surface and inside. However, since the carbon material obtained by this method has metallic silicon remaining in the molded body, high-temperature properties such as creep deformation at high temperatures are significantly deteriorated, and the mechanical properties are not always excellent.

(Means for Solving the Problems) 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 that exhibits little deterioration under high-temperature oxidizing atmospheres.

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

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

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) derived from a polycyclic aromatic compound in a mesophase state constituting the polymer; crystalline carbon, or crystalline carbon and amorphous carbon; if) non-oriented crystalline carbon and/or amorphous carbon derived from an optically isotropic polycyclic aromatic compound constituting the polymer; and 1ii) an amorphous phase consisting essentially of Si, C and O, and/or crystalline ultrafine particles and amorphous SiOx (0 <x≦2)
It is an aggregate consisting of, and the proportions of the constituent elements are Si: 30-70% by weight, C: 20-70% by weight.
60% by weight and 0.5-10% Si-
It consists of C-0 substance.

All "parts" in the following description are parts by weight, r%.
is "% by weight".

The carbonaceous inorganic material of the present invention has the above constituent components i), it)
and 1ii), Si; 0.5 to 50%,
It consists essentially of C: 40-97% and O: 0.1-10%.

The crystalline carbon that is a constituent of this carbonaceous inorganic material is 50%
A fine lattice image corresponding to three or two (002) planes oriented in the fiber axis direction was observed using a high-resolution electron microscope with a crystallite size of 0 Å or less and a resolution of 1.5 people. It is a graphite crystal with ultra-fine particles.

The ratio of component 1ii) to 100 parts of the total of components i) and it) in this carbonaceous inorganic material is 0.5
-1900 parts, and the ratio of constituent components i) and ii) is l:0.02-4.

If the ratio of component 1ff) to 100 parts of the total of component i) and it) is less than 0.5, it is almost the same as a simple carbon material, and no improvement in oxidation resistance or wear resistance can be expected. If it exceeds 1,900 parts, the molded product is almost the same as a molded product made only of silicon carbide, and a carbonaceous material with excellent high-temperature properties and lubricity cannot be obtained.

In the carbonaceous inorganic material of the present invention, microcrystals with a small interlayer interval are effectively generated, and silicon atoms are distributed very uniformly so as to surround the microcrystals.

The carbonaceous inorganic material of the present invention comprises: i) a bonding unit (Si CH) or a bonding unit (Si-
It mainly consists of CH2) and bonding units (Si-3i),
The silicon atom has a side chain group selected from the group consisting of a hydrogen atom, a lower alkyl group, a phenyl group, and a silyl group, and the total number of bonding units (Si CHz) versus bonding units (Si-3i)
At least a part of the silicon atoms of the organosilicon polymer in which the ratio of the total number of a polycyclic aromatic compound consisting of a mesophase state obtained by heat-treating a combined random copolymer and ii) petroleum-based or coal-based pitch, or a mesophase and an optically isochastic phase (hereinafter, both are collectively referred to as " A first method of obtaining a silicon-containing polycyclic aromatic polymer by heating-reacting and/or heating-melting the ``mesophase polycyclic aromatic polymer'' at a temperature in the range of 200 to 500°C.
Step: The silicon-containing polycyclic aromatic polymer, or the mixed powder of the silicon-containing polycyclic aromatic polymer and its calcined fine powder, is subjected to a conventional method such as mold pressing, isostatic isostatic pressing, hot pressing, etc. A second step of molding the molded body using the above-mentioned molded body, a third step of inorganicizing the molded body by performing infusibility treatment if necessary, and then firing it in a vacuum or an inert gas at a temperature of 800 to 3000 ° C. A fourth step of increasing the density by repeatedly impregnating the pores of the obtained carbonaceous inorganic material with a melt or solution of a silicon-containing polycyclic aromatic polymer, firing, and mineralizing the material as necessary. It is provided by a manufacturing method consisting of the following.

Note that it is also possible to manufacture the above-mentioned second to fourth steps as one step by high-temperature hot pressing or the like.

Each of the above steps will be specifically explained.

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 metallic sodium is heated in an inert gas for 400 min. Obtained by heating above °C.

The organosilicon polymer has a bonding unit (Si CHz),
or bonding unit (Si-3i) and bonding unit (Si-CH,
), and the ratio of the total number of bond units (Si-CH, ) to the total number of bond units (Si-3i) is 1:0 to 20.
is within the range of

The weight average molecular weight (Mw) of the organosilicon polymer is 300 to 1000 for boat fishing, and those with Ml of 400 to 800 are random copolymers that are intermediate raw materials for obtaining excellent carbonaceous inorganic materials. Particularly preferred for preparing i).

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

The above pitch contains 5 to 9 components insoluble in organic solvents such as benzene, toluene, xylene, and tetrahydrofuran.
It is preferable that the content is 8% by weight, and if less than 5% by weight pitch is used as a raw material, the residual rate of the molded product during mineralization will be low, pores will easily remain, and it will be difficult to crystallize, so it is excellent. Furthermore, if more than 98% by weight of pitch is used as a raw material, insoluble and infusible caulking materials are likely to be produced, which is disadvantageous in molding.

Weight average molecule of this pitch! (MW) is 300-30
00 and the melting point is 70-200°C.

The weight average molecular weight is a value determined as follows. That is, if the pitch does not contain organic solvent insoluble components for gel permeation chromatography (GPC) measurement, such as benzene, toluene, xylene, tetrahydrofuran, chloroform, and dichlorobenzene, the pitch is directly measured by GPC, and the pitch is determined from the above organic solvent insoluble components. If it contains, it is hydrogenated under mild conditions to change the organic solvent-insoluble components to the organic solvent-soluble components, followed by GPC measurement. (The weight average molecular weight of the polymer containing organic solvent insoluble matter is the value obtained by performing the same treatment as above).

Random copolymer i) is prepared by adding the above pitch to the organosilicon polymer, preferably at a concentration of 250 to 50% in an inert gas.
It is prepared by a heating reaction at a temperature in the range of 00°C.

The proportion of pitch used is 1 per 100 parts of organosilicon polymer.
Preferably it is 0-1900 parts.

If the ratio of pitch used is too small, the silicon carbide component in the resulting carbonaceous inorganic material will increase, which will impair the lubricity and high-temperature properties of carbon in a non-oxidizing atmosphere, and the ratio will decrease. If it is excessively large, the silicon carbide component will decrease, and the oxidation resistance and wear resistance of the obtained carbonaceous inorganic material will decrease.

If the reaction temperature of the above reaction is too low, it will be difficult to form bonds between silicon atoms and aromatic carbon, and if the reaction temperature is too high, the generated random copolymer will be undesirably decomposed and its molecular weight will become high. .

The mesophase polycyclic aromatic compound if) is, for example, petroleum-based or coal-based pitch heated to 300 to 500% in an inert gas.
It can be prepared by heating to °C and conducting polycondensation while removing the soft fraction produced.

If the temperature of the condensation polymerization reaction is too low, the growth of the condensed ring will not be sufficient, and if the temperature is too high, an insoluble or infusible product will be produced due to coking.

The mesophase polycyclic aromatic compound it) has a melting point of 20
The temperature range is from 0 to 400℃, and the weight average molecular weight is 2.
00 to 10000.

Among the mesophase polycyclic aromatic compounds ii), 20
Carbonaceous inorganic materials that have an optical anisotropy of ~100% and contain 2-60% quinoline-soluble matter and 30-100% insoluble matter in benzene, toluene, xylene, or tetrahydrofuran are Particularly preferred for improving properties.

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

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

The weight average molecular weight of the silicon-containing polycyclic aromatic polymer is 2
00-11000, and the melting point is 200-400°C.

2nd step: The silicon-containing polycyclic aromatic polymer obtained in the 1st step or the mixed powder of the silicon-containing polycyclic aromatic polymer obtained in the 1st step and its calcined fine powder is finely pulverized. It can be molded using the following carbon material molding method. In addition, the calcination is 8
It can be carried out at temperatures ranging from 00 to 1300°C.

In addition, the molding method can be arbitrarily selected from among the usual molding methods for carbon materials, taking into account the shape, size, purpose, productivity, etc. of the molded object. In order to manufacture with high productivity, the dry mold press method is used, and in order to obtain a molded product with a slightly complicated shape, the isostatic isostatic pressing method (rubber press molding method) melts and molds the polymer. Examples of the method include hot press molding, injection molding, and extrusion molding.

In addition, when molding a mixture of the polymer and its calcined product, the proportion of the polymer and its calcined product used depends on the shape of the molded product,
It can be determined as appropriate by taking into account usage, cost, etc.

Third step: The molded body is subjected to infusibility treatment if necessary.

A typical method for infusibility is to heat the molded article in an oxidizing atmosphere. The infusibility temperature is preferably 50 to 4
The temperature is in the range of 00°C. If the infusibility temperature is too low, no polymerization will occur, and if this temperature is too high, the polymer will burn.

The purpose of infusibility is to make the polymer constituting the molded object into a three-dimensional structure that is infusible and insoluble, so that it does not melt during the next step of mineralization and maintains the shape of the molded object. The gases that make up the oxidizing atmosphere during infusibility are:
Examples include air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, and mixed gases thereof.

As an infusible method other than the above, a method is also adopted in which the molded body is irradiated with T-rays or electron beams in an oxidizing atmosphere or a non-oxidizing atmosphere, while being heated at a low temperature as necessary. be able to.

The purpose of this irradiation with gamma rays or electron beams is to further polymerize the polymer constituting the molded body, thereby preventing the matrix from melting and losing the shape of the molded body.

The appropriate dose of γ-rays or electron beams is 106 to IQIO lands.

Irradiation can be carried out in a vacuum, an inert gas atmosphere, or an oxidizing gas atmosphere such as air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, and mixtures thereof.

Infusibility by irradiation can be carried out at room temperature, and if necessary, infusibility can be achieved in a shorter time by heating in the temperature range of 50 to 200°C.

The infusible molded body is heated in vacuum or inert gas,
It is mineralized by firing at a temperature in the range of 800-3000°C.

It is estimated that during the heating process, mineralization becomes intense from about 700°C and is almost completed at about 800°C. Therefore, the firing is preferably performed at a temperature of 800°C or higher. Furthermore, since obtaining a temperature higher than 3000°C requires expensive equipment, firing at a higher temperature than 3000°C is not practical from a cost standpoint.

Note that the infusibility step can be omitted by extremely slowing down the temperature increase rate for mineralization in this step, or by using a shape retaining means such as a jig or powder head for retaining the shape of the molded object. Furthermore, in the second step of molding, the third step itself can be omitted by using a high-temperature hot press method.

Fourth step: The carbonaceous inorganic material obtained in the third step is impregnated with the melt, solution, or slurry of the silicon-containing polycyclic aromatic polymer, and then infusible, fired, and mineralized as necessary. This makes it possible to increase the density and strength of carbonaceous inorganic materials.

Impregnation may be performed using any of a melt, solution, or slurry of the silicon-containing polycyclic aromatic polymer; Alternatively, after impregnating the slurry and promoting penetration into micropores under reduced pressure, the temperature is raised while distilling off the solvent, and the temperature is increased to 10 to 500%.
By applying pressure to kg/cJ, the pores are filled with the polymer melt.

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

The presence of Si, C, and O in the component ii) can be controlled by the mineralization temperature in the third and fourth steps.

When it is desired to obtain an amorphous substance consisting essentially of Si and C10, it is preferable to set the mineralization temperature to 800 to 1000'C, and to obtain an amorphous substance consisting essentially of β-SiC and amorphous Sin (however, O <x≦2), a temperature of 1700°C or higher is suitable.

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

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

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

Therefore, this carbonaceous inorganic material has excellent mechanical properties, oxidation resistance, and wear resistance, and is excellent as a material for various brakes and heat-resistant structures.

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

Reference Example 1 (Production method of Polymer I) 2.5 I of anhydrous xylene in a 51-meter flask! , and 400 g of sodium were added, heated under a nitrogen gas stream to the boiling point of xylene, and 1 liter of dimethyldichlorosilane was added dropwise over 1 hour. After the dropwise addition was completed, the mixture was heated under reflux for 10 hours to form a precipitate. The precipitate was filtered and washed with methanol and then water to obtain 420 g of white powder polydimethylsilane.

400 g of this polydimethylsilane was charged into a 31-hole flask equipped with a gas inlet tube, a stirrer, a condenser, and a distillation tube, and heated at 420 degrees under a nitrogen stream for 50-7 minutes while stirring.
C. to obtain 350 g of a colorless and transparent slightly viscous liquid in a distillation receiver.

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

When the infrared absorption spectrum of this substance was measured, it was found that 6
SiCH at 50~900cm-' and 1250C11-'
absorption of s, absorption of Si-H at 2100C11-', 10
Si-CHl near 1020C1' and 1355cm-'
-3i absorption, C-H absorption at 2900 cm-1 and 2950 cm-', and when the far-infrared absorption spectrum of this substance was measured, S at 380C11-'
Since absorption of i-Si is observed, the obtained liquid substance mainly consists of (Si CHl) bond units and (s
1-3i) It was found to be an organosilicon polymer consisting of bonding units and having a hydrogen atom and a methyl group in the silicon side chain.

From the measurement results of nuclear magnetic resonance analysis and infrared absorption analysis, this organosilicon polymer is a polymer in which the ratio of the total number of (Si CH3) bond units to the total number of (Si-3i) bond units is approximately 1:3. This was confirmed.

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

When we measured the infrared absorption spectrum of this substance, absorption peaks similar to those above were observed, and this substance mainly consists of (S 1-CH,) bond units and (Si-3t) bond units, and It turned out to be an organosilicon polymer containing hydrogen atoms and methyl groups.

From the measurement results of nuclear magnetic resonance analysis and infrared absorption analysis, this organosilicon polymer is a polymer in which the ratio of the total number of (Si CH) bonding units to the total number of (33-3i) bonding units is approximately 7:1. It was confirmed that there is.

On the other hand, among petroleum fractions, substances with a boiling point higher than that of light oil are removed using silica.
Fluid catalytic cracking and refinement were carried out at a temperature of 500'C in the presence of an alumina-based cracking catalyst, and a residue was obtained from the bottom of the column. Hereinafter, this residue will be referred to as FCC slurry oil.

As a result of elemental analysis, this 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 as determined by nuclear magnetic resonance analysis.

100g of the above FCC slurry oil was added under a stream of nitrogen gas.
After heating to 20° C. and distilling off the distillate at the same temperature, the residue was filtered while hot at 150″C to remove the infusible portion at the same temperature to obtain 57 g of light bone-removed pitch.

This light bone removal pitch contained 60% xylene insolubles.

25 g of the organosilicon polymer synthesized earlier and 20 d of xylene were added to 57 g of this light bone-removed pitch, the temperature was raised while stirring, and after distilling off the xylene, the reaction was carried out at 400°C for 6 hours.
3 g of random copolymer was obtained.

As a result of infrared absorption spectroscopy, this reactive component was found to have Si-H bonds (IR: 210
0C11-') and the formation of new Si-C (benzene ring carbon) bonds (IR: 1135c "1)" indicate that some of the silicon atoms in the organosilicon polymer are polycyclic aromatic rings. The copolymer was found to be a random copolymer having a portion directly bonded to the copolymer.This copolymer did not contain any xylene-insoluble portions, had a weight average molecular weight of 1400, and a melting point of 265°C.

This was heated and melted at 300"C and left to stand, and the light portion was removed due to the difference in specific gravity to obtain 40 g of the remainder.
It is called a).

In parallel, 400 g of FCC slurry oil was heated to 450°C under a nitrogen gas flow, and after distilling off the distillate at the same temperature, the residue was filtered hot at 200°C. Remove infusible part and remove light bone pitch 180
I got g. 180 g of the obtained light bone-removed pitch was heated under a nitrogen stream for 400 g while removing the light components produced by the reaction.
Polycondensation was carried out at °C for 8 hours, yielding 80.3 g of heat-treated pitch.
I got it.

This heat-treated pitch has a melting point of 310°C and a xylene insoluble content of 97%.
% and 20% of quinoline solubles, and the optical anisotropy of the polished surface was 95% when observed with a polarizing microscope.

This was heated and melted at 350° C. and left to stand again, and light components were separated and removed based on the difference in specific gravity to obtain 80 g of the remainder.

This and 40 g of polymer (a) were mixed and melted and heated at 350° C. for one hour in a nitrogen atmosphere to obtain a silicon-containing polycyclic aromatic polymer in a uniform state.

This polymer had a melting point of 290°C and contained 70% xylene insolubles.

Reference Example 2 (Production of Polymer ①) 50 g of light bone-removed pitch was added to 50 g of the organosilicon polymer obtained in Reference Example 1, and the mixture was reacted at 420° C. for 4 hours to obtain 48 g of a random copolymer.

In parallel, the light bone removal pitch was increased to 4 at 430'C.
Mesophase pitch was obtained by time reaction.

Equal weights 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 powder of Polymer I obtained in Reference Example 1 was heated to 800% in a nitrogen stream.
The temperature was raised to "C" to prepare a calcined body, which was finely pulverized to obtain a calcined body powder.An equal weight of Polymer I powder was added to this calcined body powder and wet-mixed. Granulated powder at 350°C1
Hot pressing was performed at 100 kg/cd to obtain a disc-shaped molded product with a diameter of 7 cm. This molded body was buried in a powder head of carbon powder to maintain its shape, and was heated at a rate of 5°C/h in a nitrogen stream for 8 hours.
After raising the temperature to 00°C, further raising the temperature to 1300°C,
Mineralized.

The bulk density of the obtained carbonaceous inorganic material was 1.50 g/c
It was ffl.

This carbonaceous inorganic material was immersed in a 50% xylene slurry of polymer (1), heated to 350°C while distilling off the xylene under reduced pressure, then impregnated under pressure to 100 kg/c+fl, and then heated at 5°C/h in air. The temperature was raised to 300°C at a rate of 300°C to make it infusible, and then mineralized at 1300°C. This impregnation and mineralization operation was repeated three more times, with a bulk density of 1.95 g/c+
1 material was obtained. The bending strength of this material is 21kg/m”
This carbonaceous inorganic material was further heated in argon for 2
When fired at 500℃, the bulk density was 1.99 g/c
d. The bending strength was improved by 24kg/IIIz. In addition, the bending strength at 1500°C in nitrogen is 25 kg/m.
+s”.

Example 2 Using Polymer I, 30% of the powder of Polymer H obtained in Reference Example 2 was added to 70% of the calcined powder obtained in the same manner as in Example 1, and the mixture was molded and mineralized in the same manner as in Example 1. Bulk density 1.
67 g/cd of carbonaceous inorganic material was obtained.

In the same manner as in Example 1, this material was impregnated with a 50% xylene slurry of polymer (1) and mineralized, and this impregnation and mineralization were repeated three times to obtain a carbonaceous inorganic material having a bulk density of 2.01 g/c4. The bending strength of this material is 23kg/mm”
Even after this product was kept at 600°C in air for 24 hours, no weight loss or strength reduction was observed.

Comparative Example 1 20% of mesophase pitch, which is the intermediate product of Reference Example 1, was added to 80% of artificial graphite powder having a bulk density of 0.15 g/c4 at the time of no load, and molded in the same manner as in Example 1. Mineralization was performed to obtain a carbon material with a bulk density of 66 g/cd.

This carbon material was impregnated with mesophase pitch and mineralized four times in the same manner as in Example 1 until the bulk density was 1.92 g/c.
A carbon material of d was obtained.

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

Comparative Example 2 The carbon material obtained in Comparative Example 1 with a bulk density of 1.66 g/c+d was sprinkled with metal silicon powder, melted and impregnated at 1500'C, and subjected to reaction sintering to obtain a carbon-silicon carbide composite material. The bending strength of the obtained material was improved to 8.2 kg/mm, but
When the bending strength was measured at 1500°C in nitrogen,
Deformation occurs due to melting of unreacted silicon, and the bending strength is 3.0
kg/m”.

Claims (1)

[Scope of Claims] An inorganic material obtained from a silicon-containing polycyclic aromatic polymer, the constituent components of which are: i) a crystalline material derived from a polycyclic aromatic compound in a mesophase state constituting the polymer; carbon, or crystalline carbon and amorphous carbon; ii) non-oriented crystalline carbon and/or amorphous carbon derived from an optically isotropic polycyclic aromatic compound constituting the polymer; and iii) an amorphous phase consisting essentially of Si, C and O, and/or crystalline ultrafine particles consisting essentially of β-SiC with a particle size of 500 Å or less and amorphous SiO_x (0<x≦ 2
), and the proportions of the constituent elements are Si: 30-70% by weight, C: 20-70% by weight.
Si-C which is 60% by weight and O; 0.5-10% by weight
A carbonaceous inorganic material characterized by comprising an -O substance.