JPH03232771A - Hybrid fiber reinforced carbonaceous composite material - Google Patents

Abstract

PURPOSE:To obtain the title composite material having excellent strength, elasticity and toughness by using hybrid fibers containing inorganic fibers obtained from specific polycyclic aromatic polymers as reinforcing materials and constituting matrix from a specific inorganic substance. CONSTITUTION:(A) An inorganic fiber which is obtained from a silicon- containing polycyclic aromatic polymer and comprise a carbonaceous material in a crystal arranged state, crystalline carbon in a non-orientated state and a Si-C-O substance, (B) an inorganic fiber which is obtained from a polycyclic aromatic polymer containing an element selected from Ti, Zr and Hf and silicon and comprise a carbonaceous material in a crystal arranged state, crystalline carbon in a non-orientated state and a Si-M-C-O substance (M is Ti, Zr or Hf) and (C) carbon fiber, glass fiber, boron fiber, etc., are prepared. Hybrid fibers containing at least one of the component A and the component B and comprising at least two selected from the component A, the component B and the component C are produced. Then the hybrid fibers are used as a reinforcing material and a carbonaceous inorganic substance having the same composition as that of the component A is utilized as matrix to give the title carbonaceous composite material.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat-resistant, wear-resistant hybrid fiber-reinforced carbon material with excellent mechanical properties.

(Prior art and its problems) Among carbonaceous inorganic composite materials reinforced with inorganic fibers, the so-called C/C composite, which uses carbon fiber as the reinforcing fiber and carbon as the inorganic matrix, has poor specific strength, specific elasticity, and non-oxidation. Excellent heat resistance, toughness, and friction properties in a harsh atmosphere,
It is promising as a heat-resistant structural material and brake material. Particularly in brake applications, practical use is progressing for aircraft and racing cars.

However, C/C composites tend to cause fatal cracks and peeling at the interface between the reinforcing material and matrix carbon, making it difficult to obtain sufficient mechanical strength. However, it is difficult to use it for a long time in an oxidizing atmosphere, and although it has excellent friction properties and lubricity, its wear resistance is not necessarily sufficient.

In order to improve this drawback and improve the interfacial adhesion between carbon fibers and matrix carbon, methods have been used in which the surface of carbon fibers is sized with various treatment agents and coated with methods such as CVD. There is.

However, with the above sizing method, it is difficult to fundamentally solve the problem of interfacial adhesion between carbon fibers and matrix carbon, and new defects and peeling occur between the treatment agent and the fibers or matrix. Some agents remain as impurities in the composite material, resulting in loss of corrosion resistance, heat resistance, etc. among the excellent properties of the C/C composite.

On the other hand, the method of coating each fiber is
It is necessary to add a process with low productivity such as a CVD process, which makes the composite material expensive, and the fiber diameter of the obtained fiber increases, which causes a loss of flexibility and freedom in composite material design. This was a significant reduction in severity.

On the other hand, when amorphous inorganic fibers such as silicon carbide fibers are used as reinforcing fibers, the adhesion of the reinforcing fibers to the carbon matrix is improved; could not be retained sufficiently, so it was not possible to improve the mechanical properties of the composite material.

On the other hand, active research and development has not been carried out to date on composite materials that use inorganic fibers other than carbon fibers as reinforcements and carbon as a matrix. It is generally
This is because inorganic fibers have drawbacks such as poor heat resistance in a non-oxidizing atmosphere. In addition, other than glass fibers, inorganic fibers such as boron fibers, alumina fibers, silicon carbide fibers, and silicon nitride fibers are more expensive than carbon fibers, which was also one of the reasons why the above research and development did not progress.

The present applicant disclosed fiber-reinforced carbon materials that solved the above problems in Japanese Patent Application No. 1-244982 and Japanese Patent Application No. 1247953.

(Means for Solving the Problems) An object of the present invention is to provide a fiber-reinforced carbon material whose reinforcing material is a hybrid fiber containing at least one of the fibers proposed above.

Another object of the present invention is to provide a hybrid fiber-reinforced carbon material with excellent mechanical properties.

Another object of the present invention is to provide a fiber-reinforced carbon material with excellent corrosion resistance, heat resistance, and oxidation resistance.

The hybrid fiber-reinforced carbon material of the present invention comprises inorganic fiber I
, inorganic fiber II, carbon fiber, glass fiber, boron fiber,
Alumina fiber, silicon nitride fiber, silicon carbide fiber, silicon carbide fiber with carbon core, and Si-M-C-0 fiber (
M represents Ti or Zr. ) The reinforcing material is a hybrid fiber which is made of at least two types of fibers selected from the group consisting of An inorganic fiber obtained from a polycyclic aromatic polymer, the constituent components of which are i) a radial structure, an onion structure, a random structure, or a core radial structure derived from a polycyclic aromatic compound in a mesophase state constituting the polymer; ii) a non-oriented carbon material derived from an optically isotropic polycyclic aromatic compound constituting the polymer; crystalline carbon and/or amorphous carbon in the state; and 1n) an amorphous phase consisting essentially of Si, C and O;
Or, it is an aggregate consisting of crystalline ultrafine particles substantially made of βSiC with a particle size of 500 Å or less and amorphous Si011 (0<x≦2), and the ratio of the constituent elements is Si; 30 to 7
0% by weight, C; 20-60% by weight and OS 0.5-1
0% by weight of an Si-C-0 substance, and the inorganic fiber II is a polycyclic aromatic polymer containing silicon and at least one element selected from the group consisting of titanium, zirconium, and hafnium. An inorganic fiber obtained from a radial structure, onion structure, random structure, core radial structure, or skin onion structure derived from a) a polycyclic aromatic compound in a mesophase state constituting the polymer. and a mosaic structure, b) an optically isotropic polycyclic aromatic compound containing an organic solvent-insoluble component constituting the polymer; crystalline carbon and/or amorphous carbon in an oriented state, and c) (1) an amorphous substance consisting essentially of Si, M, C and 0, and/or ■ substantially β-SiC, MC, It is an aggregate of crystalline ultrafine particles with a particle size of 500λ or less consisting of a solid solution of β-SiC and MC and MC+-x, and amorphous SiOy and MOz, and the proportion of the constituent element is Si; 5 to 70% by weight. , M; 0.5~
45% by weight, C: 20-40% by weight and O; 0.0
1 to 30% by weight of Si-M-C-0 material (in the above formula, M is at least one element selected from Ti, Zr, and Hf, and O<x<1.0<y≦2 , O<z≦
It is 2. ), wherein the inorganic substance is an inorganic substance obtained from a silicon-containing polycyclic aromatic polymer, the constituent components of which are i) a polycyclic aromatic substance in a mesophase state constituting the polymer; ii) crystalline carbon derived from a group compound, or crystalline carbon and amorphous carbon; ii) non-oriented crystalline carbon derived from an optically isotropic polycyclic aromatic compound constituting the polymer; / or amorphous carbon, 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; SiOx (0<x≦2)
It is an aggregate consisting of Si; 30 to 70 wt% C; 20 to 70% by weight of the constituent elements.
60% by weight and O; 0.5-10% by weight Si-
It is a carbonaceous inorganic material made of C-0 material.

Inorganic fibers I and inorganic fibers II in the present invention will be explained in detail. In the following description, "parts" are "parts by weight", and "%J" is [%J by weight].

The inorganic fiber I in the present invention includes the above-mentioned constituent components i),
ii) and ij), and S r + o.

01-29%, C; 70-99.9% and 0; 0.
001-10%, preferably Si; 0.1-25%
, C: 74-99.8% and O: 0.01-8%.

The inorganic fiber (①) in the present invention has the above-mentioned constituent components a) and b.
) and C), S 1 i 0-01 to 3
0%, M; 0.01-1O%, C; 65-99.9
% and O; 0.001-10%, preferably Si; 0.
1-25%, M; 0.01-8%, C; 74-99.8
% and O: substantially composed of 0.01 to 8%.

Crystalline carbon, which is a component of inorganic fiber I and inorganic fiber II, has a crystallite size of 500λ or less, and in a high-resolution electron microscope with a resolution of 1.5 people, 3 and 2 A crystallites oriented in the fiber axis direction are observed. It is an ultrafine graphite crystal in which a fine lattice image corresponding to the (002) plane can be observed. Crystalline carbon in inorganic fibers has radial structure, onion structure, random structure, core-radial structure,
It can have a random structure including a skin onion structure, a mosaic structure, and a partially radial structure. This is due to the presence of mesophase polycyclic aromatic compounds in the raw materials.

Total sum of constituent components i) and ii) in inorganic fiber ■ 10
The ratio of component iii) to 0 parts is 0.015~
200 parts, and the ratio of components i) and ii) is 1
:0.02-4.

When the ratio of component iii) to 100 parts of the total of components i) and ii) is less than 0.015, the fiber is almost the same as pitch fiber, and the oxidation resistance and interfacial adhesion with the matrix are not improved. If the above ratio exceeds 200 parts, graphite fine crystals will not be effectively generated and fibers with a high elastic modulus will not be obtained.

Total sum of constituent components a) and b) in this inorganic fiber H 1
The ratio of component C) to 00 parts is 0°015-20
0 parts, and the ratio of components a) and b) is 1:0
．． 02-4.

If the ratio of component C) to 100 parts of the total of components a) and b) is less than 0.015, the fibers are almost the same as pitch fibers, and no improvement in oxidation resistance or wettability can be expected. If the proportion exceeds 200 parts, fine graphite crystals will not be effectively generated and fibers with high elastic modulus will not be obtained.

In inorganic fiber 1 and inorganic fiber 2, microcrystals with a small interlayer spacing and three-dimensional arrangement are effectively generated, and silicon atoms are distributed very uniformly so as to wrap around the microcrystals. There is.

Next, a method for producing inorganic fiber I and inorganic fiber II in the present invention will be explained.

Inorganic fiber I can be manufactured in the following first to fourth steps.

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. It can be obtained by heating above ゛C.

The organosilicon polymer has a bonding unit (S+ CHz),
Or bonding unit (Si CHz) and bonding unit (3i-3
i) The ratio of the total number of bonding units (Si-CH2) to the total number of bonding units (Si-3i) is 1:0 to 2.
It is within the range of 0.

The weight average molecular weight (Ml) of the organosilicon polymer is 300 to 1000 for boat fishing, and those with an MI of 400 to 800 are suitable for precursor weight, which is an intermediate raw material for obtaining excellent carbon-based inorganic fibers. Particularly preferred for preparing coalescence (1).

Another starting material, the polycyclic aromatic compound, is a pinch obtained from petroleum and/or coal, and a particularly preferable pitch is heavy oil obtained by fluid catalytic cracking of petroleum, or by distilling the heavy oil. These are the distillate components or residual oils obtained by the above methods, and the pitch obtained by heat-treating them.

In the above pinch, there are 5 to 9 components insoluble in organic solvents such as benzene, toluene, xylene, and tetrahydrofuran.
Preferably, the content is 8% by weight. If pitch containing less than 5% by weight of the above-mentioned insoluble components is used as a raw material, inorganic fibers with excellent strength and elastic modulus cannot be obtained;
If more than % by weight of pinch is used as a raw material, the molecular weight of the copolymer will increase sharply, and coking may occur in some cases, making spinning difficult.

The weight average molecular weight CM, 1") of this pitch is 100~
It is 3000.

The weight average molecular weight is a value determined as follows. That is, if the bi-nochi does not contain components insoluble in organic solvents for gel permeation chromatography (C; PC) measurement, such as benzene, toluene, xylene, tetrahydrofuran, chloroform, and dichlorobenzene, it can be directly subjected to GPC.
If the pitch contains the organic solvent-insoluble components, it is hydrogenated under mild conditions to convert the organic solvent-insoluble components to the organic solvent-soluble components, and then measured by GPC. below,
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.

Precursor polymer (1) is prepared by adding petroleum-based or coal-based pitch to an organosilicon polymer, and preparing the mixture preferably at 250% in an inert gas.
It is prepared by a heating reaction at a temperature in the range of ~500°C.

The ratio of pitch used is 8 parts per 100 parts of organosilicon polymer.
It is preferable that it is 3-4900 parts.

If the ratio of pitch used is too small, the amount of silicon carbide in the resulting inorganic fiber will increase, making it impossible to obtain an inorganic fiber with a high modulus of elasticity. , the silicon carbide component decreases, making it impossible to obtain inorganic fibers with excellent interfacial adhesion with matrix carbon and oxidation resistance.

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 resulting precursor polymer (1) will be violently decomposed and its molecular weight will increase. Undesirable.

The mesophase polycyclic aromatic compound (2) 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 (2) has a melting point of 20
The temperature is in the range of 0 to 400°C, and the weight average molecular weight is in the range of 200 to 1oooo.

Among the mesophase polycyclic aromatic compounds (2), 20
Those having an optical anisotropy of 100% to 100% and containing 30 to 100% insoluble matter in benzene, toluene, xylene or tetrahydrofuran are particularly preferred in order to obtain inorganic fibers with excellent mechanical performance.

In the first step, the precursor polymer (1) and the mesophase polycyclic aromatic compound (2) are heated and melted and/or reacted in a temperature range of 200 to 500°C to form a silicon-containing polycyclic aromatic polymer. Prepare the spun polymer.

The mesophase polycyclic aromatic compound (2) is preferably used in an amount of 5 to 50,000 parts per 100 parts of the precursor polymer (1). If it is less than 5 parts, the mesophase content in the product will be insufficient, resulting in high elasticity. If the amount is more than 50,000 parts, an inorganic fiber with excellent interfacial adhesion with matrix carbon and oxidation 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 spinning polymer, which is a silicon-containing polycyclic aromatic polymer obtained in the 1st step, is heated and melted, and in some cases, it is filtered to remove substances that are harmful during spinning, such as microgels and impurities. This is then spun using a commonly used synthetic fiber spinning device.

The temperature of the spinning dope during spinning varies depending on the softening temperature of the raw material polymer, but a temperature in the range of 220 to 420°C is advantageous.

In the spinning device, a spinning tube is attached as necessary,
After setting the atmosphere in the spinning tube to one or more atmospheres selected from the group consisting of air, inert gas, hot air, hot inert gas, steam, and ammonia gas, the winding speed is increased to create a thin diameter. fibers can be obtained. The spinning speed in the melt spinning is determined by the average molecular weight of the raw materials,
Although it varies depending on the molecular weight distribution and molecular structure, 50 to 500
A range of 0 m/min is preferable.

Third step: The spun fibers obtained in the second step are made infusible under tension or non-tension.

A typical infusibility method is to heat spun fibers 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, the polymers that make up the spinning filament will not form.
Also, if this temperature is too high, the polymer will burn.

The purpose of infusibility is to make the polymer that makes up the spun fibers into a three-dimensional structure that is infusible and insoluble, so that it does not melt during the next firing process and does not fuse with adjacent fibers. It is. Gases constituting the oxidizing atmosphere during infusibility include air, ozone, oxygen, chlorine gas, bromine gas, ammonia gas, and mixed gases thereof.

As an infusible method different from the above, spun fibers are infusible by T-ray irradiation or electron beam irradiation in an oxidizing or non-oxidizing atmosphere, under tension or no tension, while heating at a low temperature as necessary. method can also be adopted.

The purpose of irradiating with gamma rays or electron beams is to further polymerize the polymer that forms the spun fibers.
The purpose is to prevent the spun yarn from melting and losing its fiber shape.

The appropriate dose of gamma rays or electron beams is 106 to 1010 rand.

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.

If infusibility is carried out without tension, the spun fibers will shrink and take on a wavy shape, but this can sometimes be corrected in the next firing process, and tension is not necessarily required. In this case, good results can be obtained if the tension is greater than that which can at least prevent the spun fibers from shrinking and becoming wavy during infusibility.

The tension to be applied during infusibility is 1 to 500
The range of g/■2 is preferable; even if a tension of less than Ig/++oa2 is applied, it is not possible to apply tension that will not cause the fibers to slack, and if a tension of more than 500 g/m" is applied, the fibers will break. There are things to do.

Fourth step: By firing the infusible yarn obtained in the third step at a temperature in the range of 800 to 3000'C in a vacuum or inert gas atmosphere, the inorganic fiber 1 mainly consisting of carbon, silicon, and oxygen is formed. can get.

In the firing process, it is not necessarily necessary to apply tension, but high-temperature firing while applying tension in the range of 0.001 to 100 Kg/Wl'' makes it possible to obtain high-strength inorganic fibers with less bending.

In the heating process, it is estimated that 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. Further, 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.

The distribution state of silicon in the inorganic fiber of the present invention can also be controlled by the atmosphere during firing and the size and concentration of mesophase in the raw material. For example, when the mesophase is grown to a large size, the silicon-containing polymer is easily extruded into the fiber surface phase, and a silicon-rich layer can be formed on the fiber surface after firing.

Inorganic fiber (1) can be produced in the following steps 1 to 4.

First step: A precursor polymer (1) is prepared by mixing with an organic silicon polymer in the same manner as the method for preparing the precursor polymer (1) in the first step of producing inorganic fibers.

Next, the precursor polymer (1) and the transition metal compound represented by the formula MX are reacted at a temperature in the range of 100 to 500'C to prepare a random copolymer (3).

In the above MX, M is at least one element selected from Ti, Zr and Hf, and X is formed by condensation,
M may be anything as long as it can be bonded directly or via an oxygen atom to the silicon of the precursor polymer (1), and is preferably a halogen atom, an alkoxy group, or a complex-forming group such as β-diketone, although there is no particular limitation. .

If the above reaction temperature is too low, the precursor polymer (1) and the formula M
If the condensation reaction with may be condensed and have a high molecular weight, or in some cases M
4 volatilizes, which is not preferable.

- For example, when M is Ti and X is 0C4Hq, a suitable reaction temperature is 200-400°C.

Through this reaction, a random copolymer (3) in which at least some of the silicon atoms of the precursor polymer (1) are bonded to the metal M directly or via oxygen atoms is prepared.

The metal M can be bonded to the silicon atom of the precursor polymer (1) in the form of a side chain in a bonding mode such as -MX or 10-MXI, or can be bonded directly to the silicon atom of the precursor polymer (1) or A bonding mode in which the bond is cross-linked via oxygen may also be used.

As a method for preparing the random copolymer (3), in addition to the above-mentioned method, it is also possible to prepare the random copolymer (3) by reacting an organosilicon polymer with MX and further reacting the resulting product with a pinch. .

In the first step, the random copolymer (3) and the mesophase polycyclic aromatic compound (2) are heated and/or
Alternatively, a metal-containing polycyclic aromatic polymer is prepared by heating and melting.

Mesophase polycyclic aromatic compound (2) is an inorganic fiber ■
It is prepared in the same manner as the preparation method described in the first step of production.

The mesophase polycyclic aromatic compound (2) 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 mesophase polycyclic aromatic compounds, 20 to 10
0%, especially 40-100% optical anisotropy, 3
Those containing 0 to 100% of insoluble matter in benzene, toluene, xylene or tetrahydrofuran are preferred in order to obtain inorganic fibers (1) with excellent mechanical performance.

The usage ratio of the mesophase polycyclic aromatic compound (2) is 5 to 50,000 per 100 parts of the random copolymer (3).
parts, more preferably 5 to 10,000 parts; if it is less than 5 parts, the mesophase content in the product will be insufficient, making it impossible to obtain a highly elastic fired yarn; if it is more than 50,000 parts, the silicon component will be Due to the shortage, inorganic fibers with excellent matrix wettability and oxidation resistance cannot be obtained.

At least a portion of the random copolymer (3) is melted and/or heated and reacted with the random copolymer (3) and the mesophase polycyclic aromatic compound (2) in a temperature range of 200 to 500°C. A metal-containing polycyclic aromatic polymer in which is combined with the mesophase polycyclic aromatic compound (2) is obtained. However, the bond mentioned here refers to a chemical bond between silicon and carbon of a polycyclic aromatic compound, and/or a polycyclic aromatic ring moiety chemically bonded to silicon in the random copolymer (3) and a mesophase polycyclic aromatic compound. It means a physical bond such as a van der Waals bond between a group compound.

If the above melt-mixing temperature is lower than 200°C, unmelted portions will occur, making the yarn non-uniform and having a negative effect on the strength and elastic modulus of the inorganic fibers.If the melt-mixing temperature is higher than 500°C, the condensation reaction will occur. The process progresses violently, and the resulting polymer has a high melting point, making it extremely difficult to spin the polymer.

As a method for preparing a metal-containing polycyclic aromatic polymer,
In addition to the above-mentioned method, it is also possible to prepare a product by reacting an organosilicon polymer and pitch, adding mesophase pitch and MX simultaneously or sequentially to the resulting product, and further reacting.

The weight average molecular weight of the metal-containing polycyclic aromatic polymer is 200
~11,000 and a melting point of 200-400°C.

Second step: The spinning polymer, which is a metal-containing polycyclic aromatic polymer obtained in the first step, is spun in the same manner as in the second step of producing inorganic fiber I described above.

Third step: The spun fiber obtained in the second step is made infusible in the same manner as in the third step of producing inorganic fiber I described above.

4th step: By firing the infusible yarn obtained in the 3rd step in the same manner as in the 4th step of producing inorganic fibers ① described above, inorganic fibers II mainly consisting of carbon, M, silicon, and oxygen are obtained. .

In addition, Si-M-C which is the constituent component C) of the inorganic fiber II
The form of the -0 substance is determined by the manufacturing conditions employed in the first to fourth steps. - In terms of boat fishing, if the firing temperature in the fourth step is lower than 1000°C, S
It is substantially composed of amorphous material consisting of i, M, and C20.

On the other hand, when the firing temperature in the fourth step is, for example, 1700°C or higher, the particle size is 500 Å or less, which is substantially composed of β-SiC, MC1, a solid solution of β-SiC and MC, and MC, (where 0<x<1). ultrafine particles and SiOx (however, 0<
y≦2) and MOz (where O<Z≦2).

At an intermediate temperature, the system is composed of a mixed system of each aggregate. Further, the amount of oxygen in the inorganic fibers can be controlled, for example, by the addition ratio of MX in the first step or the infusibility conditions in the third step.

Further, the distribution state of component C) can also be controlled by the atmosphere at the time of firing and the size and concentration of mesophase in the raw material. For example, when the mesophase is grown to a large size, component C) is easily extruded into the fiber surface phase.

In the present invention, the above-mentioned inorganic fiber (■) and/or inorganic fiber (■)
The fibers that together make up the hybrid fiber include carbon fiber,
Glass fibers, boron fibers, alumina fibers, silicon nitride fibers, silicon carbide fibers, silicon carbide fibers with a carbon core, and Si-M-C-0 fibers (M represents Ti or Zr).
selected from.

The above Si-M-C-0 fibers are (i) amorphous consisting essentially of Si, M, C1 and O;
or (ii) substantially β-SiC, MC, β-SiC and M
A solid solution of C and each crystalline ultrafine particle having a particle size of 500 Å or less of M C+-x, and an aggregate consisting of amorphous SiO ii) A mixed system of crystalline ultrafine particle aggregates, (where M in the above formula represents Ti or Zr, and 0<x<
1) is an inorganic fiber consisting of This inorganic fiber is disclosed in, for example, Japanese Patent Publication No. 60-1405, Japanese Patent Publication No. 58-5286,
It can be prepared by the method described in JP 60-20485 and JP 5944403.

The fibers used as reinforcing materials in the present invention can be prepared by blending the fibers themselves in a uniaxial or multiaxial direction, or by making them into various woven fabrics such as plain weave, satin weave, mock-satin weave, twill weave, leno weave, spiral weave, and three-dimensional weave. There are two methods: using it as a chopped fiber, and using it as chopped fiber.

The proportion of the inorganic fibers defined in the present invention in the hybrid fiber is 10% by volume or more, preferably 20% to 90% by volume.
It is. If it is less than 10%, the effect of improving the mechanical properties, which is the objective of the present invention of improving the bonding strength between the inorganic fiber and the matrix and improving the reinforcing efficiency, is poor.

Looking at the hybrid state of hybrid fibers by form: (1) interlayer hybrid, in which a layer of one type of fiber is laminated with a layer of another type of fiber; (2) intralayer hybrid, in which high printing is already performed within one layer. There are two basic types, (
3) There are combinations of them. The main types of combinations are the following 6
It is a seed.

(a) Lamination of single-layer tape (layers of different fibers are alternately layered) (b) Sandwich type (layers of different fibers are layered in a sandwich) (c) Lip reinforcement (d) Mixed fiber tow (High printing of different fibers in single fiber units) (e) Lamination of mixed fiber tape (hybridization of different fibers in yarn units within a layer) (f) Mixed fiber surface layer Hybrid fiber according to the present invention The mixing ratio in the matrix is preferably 10 to 70% by volume.

If the above mixing ratio is less than 10% by volume, the reinforcing effect of the hybrid fibers will not be sufficiently expressed, and if the mixing ratio is less than 10% by volume,
If the amount exceeds 1, the amount of matrix is so small that the gaps between the hybrid fibers cannot be sufficiently filled with the matrix.

Compared to conventional carbon fibers, the use of the hybrid fiber of the present invention as a reinforcing material has the following advantages.

That is, when the use as a composite material requires excellent properties as a part or part, for example, when abrasion resistance of the surface of the composite material is required, inorganic fiber I and/or inorganic fiber It is advantageous to hybridize ■ with boron fiber, alumina fiber, silicon nitride fiber, silicon carbide fiber, carbon-core silicon carbide fiber, or 51-MC-〇 fiber; on the other hand, lubricity is required. In this case, it is advantageous to hybridize inorganic fibers I and/or inorganic fibers I and carbon fibers. In addition, when tensile strength is required only in a certain direction, high strength carbon fibers can be arranged in the strength direction to increase the strength, and in other directions reinforced with inorganic fibers ■ and/or inorganic fibers ■ to prevent compression failure. A method of preventing delamination is also effective.

Next, a method for manufacturing the hybrid fiber-reinforced carbonaceous composite material of the present invention will be explained.

First, plain weave, satin weave, mock-sawn weave,
A method in which powder of a silicon-containing polycyclic aromatic polymer is added to various textiles such as twill weave, spiral weave, and three-dimensional weave, and then hot-pressed and shaped, after impregnating the said textile with a solution or slurry of the silicon-containing polycyclic aromatic polymer. , a method of removing the solvent and heat-forming a dried prepreg sheet, melt-kneading short fibers of the hybrid fiber or chopped fiber and a silicon-containing polycyclic aromatic polymer, and forming a fiber by press molding, injection molding, etc. A containing molded body is manufactured.

As the silicon-containing polycyclic aromatic polymer used in this step, the polymer produced in the first step of producing inorganic fibers can be used as it is, but since it is not required to be made into fibers, it is possible to use silicon-containing polycyclic aromatic polymers. There is no problem in setting the composition ratio of carbon in a somewhat wide range.

That is, the ratio of pitch used in the production of the precursor polymer (1) is 10 to 49 parts per 100 parts of the organosilicon polymer.
00 parts is preferred.

In addition, in producing the fiber-containing molded article, a calcined powder obtained by calcining and mineralizing this polymer at 800 to 1000°C in an inert gas atmosphere is mixed with the silicon-containing polycyclic aromatic polymer. However, there is no harm in using it.

This calcined body powder contains Si: 0.01 to 69.9%, C1
It is preferable that the content substantially consists of 9.9% to 99.9% and O: 0.01% to 10%.

Next, the molded body is subjected to an infusible treatment, if necessary.

As the method of infusibility treatment, the method of the third step of manufacturing the inorganic fiber I can be directly adopted.

The infusible molded body is heated in vacuum or inert gas,
Firing at a temperature in the range from 800 to 3000[deg.] C. yields a mineralized, fiber-reinforced composite material with a matrix of carbon, silicon and oxygen.

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 molded object shape-retaining jig or a powder head. It is also possible to obtain a high-density composite material in the Lee process by using a high-temperature press as a forming method.

Since the high-print fiber-reinforced carbonaceous composite material obtained by calcination and mineralization contains open pores to some extent, if necessary, it may be impregnated with a melt, solution or slurry of the silicon-containing polycyclic aromatic polymer. If necessary, the composite can be made higher in density and strength by infusibility, firing, and inorganicization.

Impregnation can be carried out using any of a melt, solution, or slurry of the silicon-containing polycyclic aromatic polymer; After impregnating, promote penetration into fine pores under reduced pressure, and then raise the temperature while distilling off the solvent.
By applying pressure to 112, the pores are filled with the polymer melt.

The obtained impregnated body can be made infusible, calcined, and mineralized in the same manner as described above. Perform this operation 2~
By repeating this process 10 times, a high-density, high-strength hybrid fiber-reinforced composite material can be obtained.

(Effects of the Invention) The hybrid fiber-reinforced carbonaceous composite material of the present invention has high strength, high elasticity and toughness because the reinforcing fibers have high strength and high elasticity, and the adhesion with the carbon matrix is improved. An excellent carbonaceous composite material can be obtained. Further, due to the effects of the silicon carbide component contained in the fibers and matrix, a material with excellent oxidation resistance and wear resistance can be obtained.

Therefore, the obtained composite material has excellent mechanical properties, oxidation resistance, and abrasion resistance, and is excellent as a heat-resistant structural material for various types of brakes.

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

Reference Example 1 (Production of Inorganic Fiber ①) 2.51 g of anhydrous xylene and 400 g of sodium were placed in a No. 51 three-loaf flask, heated to the boiling point of xylene under a nitrogen gas stream, and dimethyldichlorosilane 11 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 3I2 three-lough flask equipped with a gas inlet tube, a stirrer, a condenser, and a distillation tube, and was heated at 420 g under a nitrogen flow of 50 d/min while stirring.
After heating at °C, 350 g of a colorless and transparent slightly viscous liquid was obtained in the 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
50-900c "SiCH3 absorption at 1 and 1250cm-', Si-H absorption at 2100cm-', 1020c
``Absorption of Si-CH2Si was observed near '' and 1355 cm-', absorption of CH was observed at 2900 cnr' and 2950 cm-', and when the far-infrared absorption spectrum of this material was measured, the absorption of Si-3i was observed at 380 cm-'. was observed, the obtained liquid substance was mainly composed of (S
It was found to be an organosilicon polymer consisting of i CHz) bond units and (Si-3i) bond units, and having hydrogen atoms and methyl groups in silicon side chains.

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 CHz) 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 the infrared absorption spectrum of this material was measured, absorption peaks similar to those above were observed, and this material mainly consists of (Si CHz) bond units and (Si-3i) bond units, and has hydrogen atoms and hydrogen atoms in the side chains of silicon. It turned out to be an organosilicon polymer with 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 CHz) bond units to the total number of (Si-3i) bond units is approximately 7:1. This was confirmed.

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 rectification were performed 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.

200 g of the above FCC slurry oil was heated at 450°C for 0.5 hour under a nitrogen gas flow of 21/min, and after distilling off the distillate at the same temperature, the residue was filtered while hot at 200°C. The temperature-unmeltable portion was removed to obtain 57 g of light bone-removed pitch.

This light bone removal pitch contained 25% 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, heated while stirring, distilled off the xylene, and reacted at 400°C for 6 hours to obtain 51 g of precursor polymer (1 ) was obtained.

As a result of infrared absorption spectrum measurement, this reaction product was found to contain Si-H bonds (I R: 2
100c+++-') and the formation of new SiC (carbon of benzene ring) bonds (IR: 1135C'1), some of the silicon atoms of the organosilicon polymer are directly connected to the polycyclic aromatic ring. It was found that it is a copolymer with bonded moieties.

This precursor polymer (1) contained no xylene-insoluble portion, had a weight average molecular weight of 1400, a melting point of 265°C, and a softening point of 310°C.

On the other hand, 180 g of the light bone removal pitch was heated at 400°C under a nitrogen stream while removing light bones generated by the reaction.
Time-line polymerization was performed to obtain 97.2 g of heat-treated pitch.

This heat treatment pinch has a melting point of 263°C and a softening point of 308°C.
It was a mesophase polycyclic aromatic compound (2) containing 77% of 1-xylene insoluble matter and 31% of quinoline-soluble matter, and had an optical anisotropy of 75% when observed with a polarizing microscope on the polished surface.

This mesophase polycyclic aromatic compound (2) 90 g
and 6.4 g of the precursor polymer (1) were mixed and melted and heated at 380° 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 267°C, a softening point of 315°C, and contained 70% xylene insolubles.

The above high molecular weight material is used as the raw material for spinning, and the nozzle diameter is 0°15m.
Melt spinning was performed at 360° C7 using a metal nozzle No. 5, and the resulting spun yarn was oxidized at 300° C. in air.
The fibers were made infusible and then fired at 1300°C in an argon atmosphere to obtain inorganic fibers 1 with a diameter of 8 μm.

This fiber had a tensile strength of 320 kg/m+n'' and a tensile modulus of 26 t/ma'', and was found to have a radial structure from observation of the fracture surface.

After pulverizing this inorganic fiber I, it was melted with alkali and treated with hydrochloric acid to form an aqueous solution, and then subjected to high frequency plasma emission spectrometry analysis. As a result, the silicon content in this inorganic fiber I was found to be 0.95%.

Example 2 (manufacture of inorganic fiber II) Reference example 1 was added to 57 g of the light content removed pitch obtained in reference example 1.
Add 25 g of the organosilicon polymer obtained above and 20 relatives of xylene, raise the temperature while stirring, and after distilling off the xylene, heat to 400°C.
The mixture was reacted for 4 hours to obtain 57.4 g of precursor polymer (1).

As a result of infrared absorption spectrum measurement, this precursor polymer (1) was found to contain Si-H bonds (I R
: 2100 cm-') and new Si-C (
Since the formation of carbon (carbon) bonds (IR: 1135 cm-') in the Hensen's ring was observed, the organosilicon polymer was a polymer in which some of the silicon atoms were directly bonded to the carbon atoms of the polycyclic aromatic ring. I understand.

A xylene solution (15.5 g of a 25% xylene solution) of 3.87 g of tetraoctoxytitanium [T i (OCs H17)4] was added to the precursor polymer (1157.4 g),
After xylene was distilled off, the mixture was reacted at 340°C for 1 hour to obtain 56 g of random copolymer (2).

This polymer contained no xylene-insoluble portion, had a weight average molecular weight of 1580, a melting point of 258°C and a softening point of 292°C, and was soluble in xylene.

6.4 g of the above random copolymer (2) and 90 g of the mesophase polycyclic aromatic compound (2) obtained in Reference Example 1
g were mixed and melted and heated at 380° C. for 1 hour under a nitrogen atmosphere to obtain a metal-containing polycyclic aromatic polymer in a uniform state.

The melting point of this polymer is 264°C and the softening point is 307°C.
It contained 68% xylene insoluble matter.

Using the above-mentioned high molecular weight material as a raw material for spinning, melt spinning was performed at 360°C using a metal nozzle with a nozzle diameter of 0° and 15 mm.
The obtained spun yarn was oxidized and made infusible in air at 300°C, and further fired at 1300°C in an argon atmosphere to obtain inorganic fibers with a diameter of 7.5 μm.

This fiber had a tensile strength of 358 kg/lll112 and a tensile modulus of 32 t/l1112, and observation of the fractured surface using a scanning electron microscope revealed that it had a coral-like random radial mixed structure with many overlapping crystal layers. .

After pulverizing the inorganic fibers, they were melted with alkali and treated with hydrochloric acid to form an aqueous solution, which was then subjected to high-frequency plasma emission spectroscopy (ICP).
), the silicon content was 0.95% and the titanium content was 0.06%.

Reference Example 3 (Production of Si-TiCO fiber) Polyborosiloxane was added at a ratio of 3 parts to 100 parts of polydimethylsilane synthesized by dechlorination condensation of dimethyldichlorosilane with metallic sodium, and the mixture was heated at 350° in nitrogen. A polycarbosilane having a main chain skeleton mainly composed of carbosilane units of the formula (Si-CHz) and having a hydrogen atom and a methyl group on the silicon atom of the carbosilane unit was produced by thermal condensation with C. . By adding titanium alkoxide to this polycarbosilane and cross-linking polymerizing it at 340°C in nitrogen, 100 parts of carbosilane units and 2 (Ti-C1) were added.
A polytitanocarbosilane consisting of 10 parts of titanoxane was obtained. This polymer was melt-spun and spun at 190° in air.
C to infusible, and then further heated at 1300° in nitrogen.
Sintered with C, fiber diameter 13μ, tensile strength 310kg/f
lII112, elastic modulus 16t 7mm'' (monofilament method) An inorganic fiber containing 3% titanium element consisting of silicon, titanium, carbon and oxygen was obtained. Amorphous and
A solid solution of β-8iC, Tic, β-SiC and TiC, each crystalline ultrafine particle with a particle size of T 1 cl-X (O<x<1) of about 50, and amorphous SiO□ and T
Si-Ti- consisting of a mixed system with an aggregate consisting of iO2
It was C-0 fiber.

Example 1 Inorganic fiber I obtained in Reference Example 1 and Si-Ti obtained in Reference Example 3
-Mixed fiber tow with C-0 fiber (inorganic fiber I and Si-Ti-
The volume ratio with C-0 fiber was 8:2. ) was impregnated with a 30% xylene slurry of the silicon-containing polycyclic aromatic polymer prepared in Reference Example 1, and then dried to prepare a Bripreg sheet. A square sheet with a side of 5 CI was cut out from this prepreg sheet, stacked in a mold, and
A molded article was obtained by pressing at 50''C150 kg/cm2.

This molded body was buried in carbon powder and 5'C/
The temperature was raised to 1000°C at a heating rate of h to obtain an inorganic fiber-reinforced carbon composite material.

This composite material was buried in the silicon-containing polycyclic aromatic polymer described in Reference Example 1, and placed in an autoclave under a nitrogen atmosphere for 30 minutes.
After heating to 50°C and melting, the pressure is reduced to impregnate the silicon-containing polycyclic aromatic polymer into the pores, and then 100 kg/c
After pressure impregnation treatment with sn2, the temperature was raised to 300"C at a heating rate of 5 °C/h in air, and after infusibility, it was heated to 1300 °C.
It was carbonized. Impregnation and carbonization of the silicon-containing polycyclic aromatic polymer were repeated three more times.

The bulk density of the obtained composite material was 1.78 g/crA,
Bending strength: 34 kg/II+1 [12, fiber volume content (
Vf) was 60% by volume.

The friction coefficient and wear amount of this composite material were measured, and the results are shown in Table 1.

Comparative Example 1 Tensile strength 300 kg/III [112, tensile modulus 24
t/mm" polyacrylonitrile carbon fiber plain weave fabric with resol type phenolic resin (Meisho Kasei M)
RW-3000) was dipped in a methanol solution and pulled up, the methanol was removed, and then dried to obtain a prepreg sheet. A square sheet with a side of 5 cm was cut out from this prepreg sheet, stacked in a mold, and heated to 350 kg at 200°C.
/cm" to harden the phenolic resin to obtain a molded body. This molded body was buried in carbon powder and heated to 1000'C at a heating rate of 5 °C/h in a nitrogen stream. An inorganic fiber reinforced carbon composite material was obtained.

Powder of the mesophase polycyclic aromatic compound (2) described in Reference Example 1 was added to this composite material, heated to 350°C in an autoclave under a nitrogen atmosphere, and after melting, the pressure was reduced, and the mesophase polycyclic aromatic compound (2) was added into the pores. After impregnating with the aromatic compound (2), after pressure impregnation treatment at 100 kg/cm2, the temperature was raised to 300 °C at a temperature increase rate of 5"C/h in air,
After infusibility, carbonization was performed at 1300''C. Impregnation with the mesophase polycyclic aromatic compound (2) and carbonization were repeated three more times.

The properties of the obtained composite are shown in Table 1.

Comparative Example 2 SiTi-C-0/C
produced a composite. The properties of this composite are shown in Table 1.

Table 1 However, the conditions for measuring the amount of wear using a dynamometer were as follows (the mating material was the same composite material in each case).

Inertia amount 0.06~0.08kgf-m-sec
”Rotation speed 3000-5000rpm Initial sliding speed
10~20m/sec pressing pressure 5~10
kg/c+fl Example 2 Inorganic fiber ■ obtained in Reference Example 2 and tensile strength 570 kg/Shi2
A tape made of polyacrylonitrile-based high-strength carbon fiber with a tensile modulus of 30 t/mm2 treated with the same silicon-containing polycyclic aromatic polymer as in Example 1 was pulled in one direction and shifted by 90 degrees. Layered alternately, Example 1 below
A composite material was produced in the same manner.

The fiber volume content (■,) of the obtained composite material was 20% by volume for inorganic fiber II and 20% by volume for carbon fiber, a total of 40%.
It was % by volume.

The tensile strength of this composite material in the carbon fiber reinforcement direction is 62 kg.
/+n+n” inorganic fiber ■Bending strength in reinforcement direction is 41kg
/an2, and it was a material with specificity depending on the direction of reinforcement.

Claims (1)

[Claims] Inorganic fibers I, inorganic fibers II, carbon fibers, glass fibers, boron fibers, alumina fibers, silicon nitride fibers, silicon carbide fibers, silicon carbide fibers having a carbon core, and Si-M-C
- A hybrid fiber consisting of at least two types of fibers selected from the group consisting of O fibers (M represents Ti or Zr) and containing at least one of inorganic fiber I and inorganic fiber II as a constituent component of the fiber. In a hybrid fiber-reinforced carbon material having an inorganic substance as a reinforcing material and a matrix, the inorganic fiber I is an inorganic fiber obtained from a silicon-containing polycyclic aromatic polymer, and the constituent components thereof are i) the polymer; Carbonaceous material exhibiting at least one type of crystal orientation state selected from the group consisting of a radial structure, an onion structure, a random structure, a core radial structure, a skin onion structure, and a mosaic structure derived from a polycyclic aromatic compound in a mesophase state; ii) non-oriented crystalline carbon and/or amorphous carbon derived from the optically isotropic polycyclic aromatic compound constituting the polymer; and iii) substantially composed of Si, C and O. It is an amorphous phase and/or an aggregate consisting of crystalline ultrafine particles substantially made of β-SiC with a particle size of 500 Å or less and amorphous SiO_x (0<x≦2), and the ratio of constituent elements is However, Si; 30-70% by weight C; 20-70% by weight
Si-C which is 60% by weight and O; 0.5-10% by weight
-O substance, wherein the inorganic fiber II is an inorganic fiber obtained from a polycyclic aromatic polymer containing silicon and at least one element selected from the group consisting of titanium, zirconium, and hafnium. , the constituent components of which are selected from the group consisting of a) a radial structure, an onion structure, a random structure, a core radial structure, a skin onion structure, and a mosaic structure derived from a polycyclic aromatic compound in a mesophase state constituting the polymer; b) non-oriented crystalline carbon and/or amorphous carbon derived from an optically isotropic polycyclic aromatic compound constituting the polymer; and c) (1) an amorphous material consisting essentially of Si, M, C and O, and/or 2 particles consisting essentially of β-SiC, MC, a solid solution of β-SiC and MC, and MC_1_-_x It is an aggregate of crystalline ultrafine particles with a diameter of 500 Å or less and amorphous SiO_y and MO_z, and the proportion of the constituent elements is Si: 5 to 70% by weight, M: 0.5 to
45% by weight, C: 20-40% by weight and O: 0.01-
30% by weight of Si-M-C-O material (in the above formula:
M is at least one element selected from Ti, Zr, and Hf, and satisfies 0<x<1, 0<y≦2, and 0<z≦2. ), wherein the inorganic substance is an inorganic substance obtained from a silicon-containing polycyclic aromatic polymer, the constituent components of which are i) a polycyclic aromatic substance in a mesophase state constituting the polymer; ii) crystalline carbon derived from a group compound, or crystalline carbon and amorphous carbon; ii) non-oriented crystalline carbon derived from an optically isotropic polycyclic aromatic compound constituting the polymer; / or amorphous carbon, 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; SiO_x (0<x≦2)
It is an aggregate consisting of Si, and the proportion of the constituent elements is Si; 30 ~
70% by weight, C: 20-60% by weight and O: 0.5-1
A hybrid fiber-reinforced carbonaceous composite material characterized in that it is a carbonaceous inorganic material consisting of a Si-C-O material of 0% by weight.