JPS6327308B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mineral fiber-apatite fired composite. More particularly, the present invention relates to a fired composite comprising an effective amount of mineral fiber material and a matrix amount of apatite (preferably hydroxyapatite) and a method for making the same.

The fired composite according to the present invention has as essential raw materials:
It essentially consists of a mineral fiber material as a reinforcing material and a sintered apatite fired at a low temperature as a matrix material. Regarding the raw materials, various types of mineral fibers have been developed as industrial raw materials and are commercially available. Conventionally, the use of glass fiber, for example, as a reinforcing material for composite materials has been mainly directed to poly(condensation) cured composites with special organic synthetic resin materials. As apatite raw material,
Typical examples include hydroxyapatite, carbonate apatite, fluoroapatite, and chlorapatite. High temperature calcination methods for these apatites and especially hydroxyapatites have been proposed. However, conventional high-temperature single sintered bodies generally have problems with various strengths (particularly impact and bending) and large pores due to the crystal structure of the sintered body. For example, as a method for singly sintering hydroxyapatite, various methods are known in which hydroxyapatite produced by a wet or dry method is sintered at approximately 1200°C ± 100°C without pressure or under pressure. ing. However, it seems that there has been essentially no success in using hydroxyapatite as a matrix material by firing it at a relatively low temperature as in the present invention. Also,
A non-sintered composite material has been proposed in which separately fired apatite is used as an aggregate and dispersed and hardened in an organic resin matrix. (For example, JP-A-55-50349
issue).

Conventionally, glass fibers and the like have been widely used as excellent reinforcing materials mainly in the field of synthetic resin composite materials. However, the heat resistance of these materials is generally less than about 800°C, which is outside the scope of conventional high-temperature sintering of oxidized apatite. Furthermore, carbon fiber materials, for example, generally have a heat resistance of about 500° C. in an oxygen-containing atmosphere or in the coexistence of high-temperature oxidizing substances such as apatite, so they were completely out of the question.

As mentioned above, conventional singly fired apatite has problems in strength, toughness, homogeneous porosity, etc., so the present inventor conducted research and development on a low-temperature fired composite using this as a matrix material. That is, using a mineral fiber material that has traditionally had excellent performance for synthetic resin composites, apatite is sintered under specific firing conditions within the heat-resistant temperature range of the reinforcing material to form a sintered composite. oriented towards manufacturing. According to the conventional technical knowledge of single apatite sintered bodies,
It was thought that if the firing temperature were lowered in this way, sintering would be virtually impossible, or even if it were possible, the strength etc. of the sintered body would inevitably decrease. In this regard, the present inventor has developed a method to obtain sufficient strength, etc. by firing apatite at a low temperature under pressure in the presence of water vapor derived from apatite crystallization water and preferably from adhering water. We have discovered the possibility of producing an apatite sintered body as a matrix material.

Initially, we considered fired composite materials using glass fibers, which are excellent reinforcing materials and are relatively easy to obtain, and base metal fibers, which are relatively inexpensive.
At a firing temperature of approximately 700°C, expected physical properties are not observed (note that base metal fibers also have problems with corrosion and metal outflow during use). Naturally, it was expected that there would be no significant difference even if a lower firing temperature was used, but just to be safe, we used glass fiber or carbon fiber as a reinforcing material and apatite as a matrix material to lower the firing temperature to less than 400°C and 500°C, respectively. As a result of research at calcination temperatures of less than 1,000 yen, we have, quite surprisingly, succeeded in developing composites with excellent physical properties.

The reason for this is not fully understood, but glass fibers or base metal fibers have a physical and chemical affinity for apatite at a firing temperature of about 700°C, so when a composite material of the two is fired, This is thought to be due to the fact that they sometimes deteriorate and the two come into close contact with each other, leaving no room for slippage between them against external forces. On the contrary, although the fibers have a sufficient physical affinity for apatite, they are not chemically at all or substantially inert under the firing conditions of the composite of the present invention. Therefore, in the fired composite according to the present invention, since there is a slight margin of slippage between the two components, it is thought that a composite having particularly excellent strength against impact and bending can be unexpectedly obtained. This is surprising given the fact that in conventional resin composite materials of fiber materials and synthetic resins, emphasis is placed on the adhesion affinity of both components, such as by applying adhesion promoters to the fiber materials, but when the matrix is resin In this case, the resin itself has some flexibility, so it is thought that the above problem does not occur.

One object of the present invention is to provide a mineral fiber-apatite fired composite having various strengths and, if necessary, appropriate microporosity, and a method for producing the same. Another object of the present invention is to provide a sintered composite material that takes advantage of the excellent physical properties of the composite of the present invention and is suitable for the wide range of applications described below. Other objectives will become apparent from the description below.

The fired composite of the present invention is therefore a mineral fiber-apatite fired composite characterized in that it comprises an effective amount of mineral fiber material and a matrix amount of sintered apatite fired in close contact with the material. body (composite). The mineral-based fibrous material in the fired composite is further characterized in that it is present in a substantially unmodified state.

As used herein, effective amount of mineral-based fibrous material means an amount of the material that is effective to reinforce the fired composite and that can be bonded as a composite by the fired apatite matrix. . A matrix amount of apatite means an amount of apatite within a range that allows the mineral fiber material to be combined into a composite. The relationship between the effective amount of the mineral fiber material and the apatite versus the amount of matrix depends on the density of the mineral fiber, but in terms of weight percent, it is generally 0.5-70% vs. 99.5-30%, usually 1-50%
99-50% vs. 99-50%, preferably 2-40% vs. 98-60%, more preferably 5-30% vs. 95-70%, and typically 7-25% vs. 93-75%. The fired composite of the present invention may contain small amounts of optional materials (such as colorants,
Fillers, etc.) may naturally be included.

The mineral-based fibrous material used essentially as a reinforcement in the present invention has sufficient strength as a reinforcement and in the presence of moisture from less than about 800°C to about 150°C and preferably from less than about 700°C to about Mineral-based (inorganic or metallic) that does not substantially denature even when baked in close contact with apatite material at a temperature of 170°C for 0.5 hours or more
fibrous materials. The fiber material preferable for the present invention (the safe heat resistance temperature as a fiber is added)
Under the above firing conditions, the temperature at which there is no substantial denaturation is approximately
800℃ or less), mullite (approximately 800℃ or less)
℃ or less), silicon carbide (approximately 800℃ or less), carbon (approximately 500℃ or less)
℃ or less), apatite glass (approx. 750℃ or less) glass, preferably alkali-resistant glass (approximately 500℃ or less), silicon titanide (approx. )
Typical examples include fibers such as: Furthermore, examples of the material include coated metal fibers on which an inorganic element or compound is coated (for example, by vapor deposition). For example, boron fibers made by vapor-depositing boron on a tungsten wire can also be advantageously used. These materials can be used alone or in any mixture. Note that the fiber material is not limited to these examples. Regarding the form and dimensions of the mineral fiber material, common technical knowledge regarding conventional glass fiber-synthetic resin composite materials can be applied. For example, the mineral fiber material may include short fibers,
It can be in the form of long fibers, fiber yarns, fiber bundles, wool-like fibers, non-woven fabrics and/or woven fabrics. In addition, in the case of short fibers, it is desirable that the fiber length is longer than that of the sintered apatite crystals.

The mineral fiber material in the fired composite of the present invention may be oriented substantially in one to three axes in the fired apatite matrix, or substantially non-oriented, depending on the purpose and use. It can exist in a state of disorder. Similarly, the distribution of the material may be such that the fibrous material is substantially uniformly dispersed in the composite matrix, or the fibrous material is dense (or sparse) toward the core and sparse (or sparse) toward the surface. can be dense).

The apatite essentially used as a matrix material in the present invention typically includes hydroxyapatite, carbonate apatite, fluoroapatite, chlorapatite, and mixtures thereof, as well as those converted to apatite during the firing process of the composite. (herein referred to as apatite precursor material).

In a broad sense, apatite is defined by the following formula (1), A ₁₀ (XO ₄ ) ₆ Zm ... (where A = Ca, Pb, Mn, Na, K, etc.; X = P,
As, V, Si, etc.; Z=OH, CO ₃ , F, Cl), the apatite used in the present invention is more limited, and its basic composition, which is its mineralogy definition, is expressed by the following formula (). Ca ₁₀ (PO ₄ ) ₆ Zm...[Here Z is OH, CO ₃ , F, and Cl, and m is a number that substantially satisfies the valence (for example, 2 or 1)]. That is,
In the above formula (), the Ca/P ratio is not necessarily stoichiometric (5/3) and may be non-stoichiometric, and usually the Ca/P ratio is about 4/3.
3 to about 11/6 and preferably about 9/6 to
It should be within the range of about 5/3, if necessary,
By uniformly mixing a non-phosphorous inorganic calcium compound (for example, calcium hydroxide) with apatite having a Ca/P ratio of less than 5/3, the Ca/P ratio can be brought close to the basic composition of 5/3.

In addition, Ca of apatite expressed by the formula ()
and P may be substituted with impurity amounts or small amounts of other atoms (eg, as shown in the definition of formula ()). In the present specification, Z in the above formula () may be one or more of OH, CO ₃ , F and Cl, and in this case, according to the one with the largest substitution amount, Z is hydroxyapatite, carbonate, etc., respectively. They are called apatite, fluoroapatite and chloroapatite. Both of these apatites belong to the same hexagonal crystal system, space group C6 ₃ /m and chemical formula number in the unit cell, and have substantially the same sinterability and similar physical properties. Note that these apatites can be chemically synthesized or obtained as a product (purified if necessary) by those skilled in the art.

From the viewpoint of applications, etc., the apatite used in the present invention is a hydroxyapatite in which Z is essentially an OH group in the above formula () and/or a majority of Z is an OH group, and the remaining amount ( preferably 10
Hydroxylic apatites in which a small amount (less than %) are _CO3 groups are generally and particularly preferred for biomedical applications.

The mineral fiber-apatite fired composite of the present invention can be produced by mixing an effective amount of the above mineral fiber material and a matrix amount of the above apatite, and adding an appropriate amount of water as needed to ensure that both of them are mixed. The fibrous material is sintered in substantially intimate contact under pressure at a temperature substantially below the denaturation temperature (but less than about 150°C to about 800°C) of the fibrous material, substantially preventing moisture loss. It can be manufactured by substantially sintering apatite. Note that the mixture of both components can also be preformed into a desired shape by compression or the like before firing. The above moisture content is such that crystal water coexisting with apatite during firing or other attached moisture is substantially 0.01 to about 25% by weight, preferably about 0.05 to about 20% by weight, based on the amount of apatite. be. As the water content increases, the amount of voids in the fired product increases, but sintering also tends to be accelerated. about 25
%, the amount of voids will generally become excessive when the pressure is relatively low. However, in the case of open heating such as the hot press method, the amount of water added may be larger.

Although the sintering mechanism of apatite has not been fully elucidated, it seems to be due to the fact that apatite is melted out depending on the firing temperature, and then these are entangled and sintered. At this time, the higher the pressure,
The above-mentioned dissolution precipitation tends to be promoted. Also,
The presence of moisture in a sealed state also tends to accelerate the solubilization. From this point of view, by employing high pressure and the presence of an appropriate amount of moisture in the firing process, the firing temperature can be significantly lowered. Separately from this, in the present invention, at least some degree of pressure is preferably applied before and/or during firing in order to bring both components into close contact with each other.

In the firing step in the present invention, techniques known in the firing or sintering industry can be employed. For example, a hot press method, a sealed pressure firing method such as an autoclave method, a high frequency heating method under pressure, an isotactic compression heating method, etc. can be advantageously used. Applications of typical firing methods are outlined below. Note that the sintering time is generally about 0.5 hours to about 30 hours.

(b) In the case of the hot press method, a mixture of the above-mentioned materials or a preform thereof is heated from about 150°C to below the denaturation temperature of the fiber material by applying a pressurized atmosphere of water vapor or an inert gas containing water vapor. (depending on the nature of the fiber, e.g. less than about 800°C) and preferably from about 150°C to about
Approximately 10Kg/cm2 ^or more at a temperature of approximately 500℃, for example approximately
Fire for 0.5 hours or more under pressure of about 10 to 1000 atmospheres. When firing the preform, since it has already been compressed, it can be fired without applying particularly high pressure (for example, at 5 kg/cm ² or more). Note that compression by the hot press method is, in principle, in the axial direction.

(b) In the case of a sealed pressurized firing method such as an autoclave method, firing is performed for 0.5 hours or more under a pressure of several tens to several thousand atmospheres at a temperature below the denaturation temperature of the fiber using, for example, an ultra-pressure resistant container. At this time, if the temperature and pressure are low, it will take a long time to bake, but if the pressure is set to 100 atmospheres or more, the temperature will rise to about 150℃.
Firing is advantageously achieved even at moderate temperatures. Therefore, the firing conditions should be about 10 kg/cm ² or more, preferably about 20 kg/cm 2 or more.
Kg/cm ² or more, for example, about 20 to about 2000 atm (up to about 3000 atm if pressure resistance allows), about 150℃ to about
This can be summarized as 0.5 hours or more at less than 800°C (preferably about 150°C to about 500°C). Note that the pressurization in this mode is substantially non-axial pressurization.

(c) In the above-mentioned sealed pressurized firing method, the above-mentioned pressurized high-frequency heating method, isobaric compression heating method, etc., a mixture or preform of composite raw materials is sealed in a substantially inert pressurized deformable container. The present invention can be achieved even more effectively when firing is performed. The firing conditions in this case are the same as those in (b) above, but preferably about 40 to about 3000 kg/cm ² , about 150 kg/cm 2
℃ to less than about 500℃ for about 0.5 hours or more. Adoption of such a sealed container has the advantage that raw material components, moisture, gas, etc. can be maintained unaltered. Note that the compression pressurization in this embodiment is substantially equal pressure compression.

The mineral fiber-apatite fired composite according to the present invention has the fiber material, which is essentially a reinforcing material, present in an unmodified state in close contact with a sintered matrix of apatite crystals, and If necessary, the sintered apatite is a sintered composite having appropriate microporosity. Due to the firing conditions of the present invention, the sintered apatite crystal has a fine structure in which fine linear and/or curved needle crystals are intertwined, and its strength is increased. i.e. the firing temperature is less than 800°C, preferably about
Below 700°C, the lower the temperature, the more fine crystals, especially fine needle-like crystals, tend to form, increasing the strength. [Note that if the firing temperature is high (for example, 1100° C.) as in the prior art, the structure will be composed of relatively large hexagonal crystal groups, resulting in a decrease in strength. ]
Furthermore, if the amount of voids becomes too large, the strength naturally decreases. Therefore, in order to obtain the composite having excellent strength and sufficient microporous voids, the above firing conditions should be relatively high pressure and low temperature, preferably within the above range. It is preferable to carry out the firing in the coexistence of moisture. Therefore, the firing temperature is approximately
Selected below 800℃.

The physical properties of the fired composite according to the present invention may vary depending on the composition of the composite raw material, firing conditions, etc., but exemplarily have numerical values within the following range.

(i) Average width of sintered apatite crystals 0.01 to 5 μmφ (ii) Average length of sintered apatite crystals 1 to 1000 μm (iii) Average pore radius of sintered apatite 5 to 1000 μm (iv) Porosity of sintered apatite 0 ~40% by volume (v) Compressive strength of fired composite 350~1000Kg/cm ² (vi) Bending strength of fired composite 1150~2500Kg/cm ² (vii) Impact strength of fired composite 30~150Kg・cm/cm ² (viii) Tensile strength of fired composites 50-150 Kg/cm ² The fired composites according to the present invention, depending on their inherent excellent physical properties, can be used in a wide range of applications, and especially in fields where various strengths are required. Advantageously applied. Typical examples include ceramic materials that require strength, electrical and electronic equipment materials, filter media, carriers for chromatography, sensor (especially for biological use) elements, ceramics for biological use (artificial bones, artificial teeth, artificial joints), and conventional materials. Examples of other applications to which fine ceramics are applied include: The various uses mentioned above can be broadly classified into industrial ceramic materials and ceramics for biological use, but ceramics for biological use require compatibility with living organisms in addition to strength and microporosity. Therefore, biocompatibility will be discussed below.

It is known that the hard tissues of mammals and especially humans (bones, teeth, etc.) are mainly composed of hydroxyapatite (specifically, hydroxyapatite containing a small amount of carbonate groups, about several percent). ing. Therefore, many studies have been reported on the use of sintered hydroxyapatite alone for artificial bones and teeth. In particular, it is recognized in this industry that a porous single sintered body having a porosity of several percent or more is somewhat satisfactory in terms of compatibility with living organisms. However, as mentioned above, hydroxyapatite single sintered bodies mainly have problems in impact strength and bending strength, so it seems difficult to put them into practical use immediately at present. On the other hand, among the fiber materials that are other raw materials in the present invention, carbon, silicon carbide, mullite, silica, alumina, apatite glass, and silicon titanide fiber materials have excellent strength and elastic modulus and are chemically free. It has advantages such as stimulation,
Moreover, it is recognized in this industry that it has a somewhat satisfactory biocompatibility.

Both components used in the present invention have satisfactory biocompatibility, and the required strength and microporosity with a porosity of about 5% to 40% are sufficiently ensured by the present invention. Therefore, the specific fiber-hydroxyapatite fired composite of the present invention can solve the above problems and provide a hard tissue material having satisfactory biocompatibility.

The present invention will be further explained below by giving typical examples. However, since all the apatites used in the present invention have substantially the same chemical structure, crystal system, sinterability, etc., the present invention The examples are not limited. That is, a person skilled in the art can, as necessary,
Similar sintered composites can be readily produced using apatite raw materials other than the apatite used in the examples below in accordance with the present disclosure.

In addition, in the following examples, all percentages are by weight.

Example 1 (comparative example) 85% powder of hydroxyapatite (Ca/P ratio 95/60), which essentially contains only hydroxyl groups, and 15% pyrolytic carbon fiber (average length 9 mm) were homogeneously mixed, and approximately 5× Preform into a cylinder with a diameter of 10 mm. Then, it is pre-dried to a moisture content of 5%. This sample is pressed and fired in a hot press at 1100° C. and 200 kg/cm ² for 2 hours. The physical properties of the fired composite after being allowed to cool are shown below.

Compressive strength 310Kg/cm ^2Bending strength 320Kg/cm ^2Tensile strength 40Kg/cm ^2Sharpey impact strength 8Kg・cm/cm ^2When observing the fracture surface of the sample in the bending test, it was found that the fibers were cut on the fracture surface. ing.

Example 2 (Comparative Example) A single sintered body is produced in the same manner as in Example 1 above, using only apatite powder without using the carbon fiber material. The physical properties of the sintered body after cooling are shown below.

Compressive strength 320Kg/cm ^2Bending strength 310Kg/cm ^2Tensile strength 35Kg/cm ^2Sharpy impact strength 7Kg・cm/cm ^2The crystals of the apatite sintered body obtained by the conventional method are shown in Figure 2 (magnification x 7500). . It is noted that the crystal has a coarse hexagonal structure.

Example 3 (Comparative Example) In Example 1 above, 15% glass fiber (average length 9 mm) was used instead of carbon fiber, and preforming and
Dry and bake under the same conditions.

The physical properties of the composite after cooling are shown below.

Compressive strength: 305 Kg/cm ² Bending strength: 310 Kg/cm ² Tensile strength: 45 Kg/cm ² Shallie impact strength: 8 Kg cm/cm ² Note that the fibers were similarly cut on the fracture surface in the bending test.

In Examples 1 and 3 (comparative example) above, the fact that the fibers were cut at the fracture surface in the bending test indicates that the fibers were degraded. Furthermore, it should be noted that the hot press sintering process in Examples 1-3 (comparative examples) was carried out without the application of pressurized steam. This sintering process corresponds to the sintering of the apatite in the absence of water, since in the steps of Examples 1 to 3 virtually all of the water present in the apatite is rapidly evaporated away from the mold of the hot press. be.

Example 4 A homogeneous mixture of apatite and mullite fibers (average length 9 mm) in the same proportions as in Example 1 above is predried to a moisture content of 5% without preforming. This is sealed in a pressure-deformable silver tube and placed in a pressure-resistant heating container.
Pressure firing is performed at 300°C and 1000 kg/cm ² for 5 hours. The physical properties of the fired composite after being allowed to cool are shown below.

Compressive strength 610Kg/cm ^2Bending strength 1290Kg/cm ^2Tensile strength 85Kg/cm ^2Sharpey impact strength 110Kg/cm/cm ^2In addition, at the fracture surface in the bending test, the mullite fibers were slightly pulled out from the wave section and cut. There is.

Example 5 (Example) Calcium hydroxide powder was mixed with hydroxyapatite powder (Ca/P ratio = 95/60), which essentially contains only hydroxyl groups, and the Ca/P ratio was adjusted to approximately 5/3. do. 85% of this mixed powder and 15% of silicon carbide fibers (average length 9mm) were mixed homogeneously, and the water content was 5%.
to dry. This was sealed in the same manner as in Example 4 and fired under pressure under the same conditions. The physical properties of the fired composite after cooling are shown below.

Compressive strength 650Kg/cm ² Bending strength 1355Kg/cm ² Tensile strength 130Kg/cm ² Example 6 (Reference example) Hydroxyapatite (Ca/P ratio = 95/60), which essentially contains only hydroxyl groups, is mixed with 5% moisture. Adjust to. This hydroxyapatite powder was sealed in a pressure-deformable silver tube and heated to 500°C using a pressure-resistant heating container.
Baked for 3 hours under a pressure of 1000 kg/cm ² . The obtained apatite sintered body exhibits the following physical properties.

Compressive strength 520Kg/ ^cm2 Bending strength 710Kg/cm2 Tensile strength 55Kg/ ^cm2 Impact strength (sharpy ⁾ 16Kg・cm/ ^cm2 Porosity (open micropores) Approximately 24% by volume The crystals of this apatite sintered body Diagram (magnification
30000). Therefore, it is recognized that the crystals of sintered apatite, which is the matrix material in the present invention, are composed of fine needle-like crystals and have a fine structure in which the crystals are intertwined with each other.

[Brief explanation of the drawing]

FIG. 1 is a scanning electron micrograph (magnification x 30,000) of a sintered hydroxyapatite body according to the present invention;
The fine needle-like crystal structure of the sintered body is shown. FIG. 2 is a scanning electron micrograph (magnification x 7500) of an apatite sintered body produced by a conventional high-temperature sintering method, showing the coarse hexagonal crystal structure of the conventional apatite sintered body.

Claims (1)

[Claims] 1. An effective amount of reinforcing mineral fiber material (excluding the case of carbon fiber alone), and a material that is in close contact with the fiber material and prevents moisture loss at a low temperature of less than 800°C under pressure. consisting essentially of a matrix amount of sintered apatite selected from hydroxyapatite, carbonate apatite, fluoroapatite, chlorapatite, and mixtures thereof, calcined under conditions that substantially prevent 1. A mineral fiber-apatite fired composite material, which forms a matrix material having a fine crystalline structure having a high strength, and is characterized in that the fiber material is substantially unmodified. 2. The composite of claim 1, wherein the fibrous material ranges from 1 to 50% by weight and the apatite ranges from 99 to 50% by weight. 3 The basic composition of the apatite is expressed by the following formula, and the atomic ratio of calcium to phosphorus (Ca/P ratio)
is an apatite or a mixture thereof in the range of 4/3 to 11/6, the complex of claim 1 or 2, Ca ₁₀ (PO ₄ ) ₆ Zm where Z is OH, CO ₃ , F, and Cl, and m is a number satisfying the valence. 4. The composite according to any one of claims 1 to 3, wherein the fibrous material is in the form of short fibers, long fibers, fiber yarns, fiber bundles, wool-like fibers, nonwoven fabrics, and/or woven fabrics. 5 The fiber material is mullite, silicon carbide, carbon, apatite glass, glass, silicon titanide, silica,
The composite according to any one of claims 1 to 4, which is selected from alumina fiber material and inorganic coated metal fiber. 6. A composite according to any one of claims 1 to 5, wherein the fibrous material is oriented in substantially one to three axes. 7. The composite of any of claims 1-6, wherein the composite material is substantially uniformly dispersed in a matrix. 8. Claims 1 to 7, wherein the apatite is hydroxyapatite essentially containing only hydroxyl groups and/or hydroxyapatite in which the hydroxyl groups are substituted with a small amount of _CO3 group. Any complex. 9. The composite according to any one of claims 1 to 8, wherein the firing temperature is less than 700°C. 10. The composite according to any one of claims 1 to 9, which is a ceramic for living body. 11 A matrix amount of apatite raw material selected from the group consisting of hydroxyapatite, carbonate apatite, fluoroapatite, chlorapatite, mixtures thereof, and apatite precursor materials thereof and an effective amount of mineral fiber material for reinforcement (however, carbon fiber alone ) in substantially intimate contact under pressure at a temperature below 800°C and below the denaturation temperature of the fibrous material corresponding to at least the water of crystallization of the apatite. The sintered apatite matrix material has a fine crystalline structure with sufficient strength, and the fiber material is substantially unmodified. A method for producing a mineral fiber-apatite fired composite. 12. The method for producing a composite according to claim 11, wherein the firing step is carried out at a temperature range from 150°C to below the denaturation temperature of the fiber material under the firing conditions and under a pressure of 10 Kg/cm ² or more. 13. The method for producing a composite according to claim 11 or 12, wherein the calcination is carried out in the presence of less than 20% water other than crystallization water of apatite. 14. The method for producing a composite according to any one of claims 11 to 13, wherein the mixed material is sealed in a pressurized deformable container and fired. 15. A method for making a composite according to any of claims 11 to 14, wherein the fibrous material ranges from 1 to 50% by weight and the apatite ranges from 99 to 50% by weight. 16 The basic composition of the apatite is expressed by the following formula, and the atomic ratio of calcium to phosphorus (Ca/P
Claim 1, wherein the ratio) is apatite in the range of 4/3 to 11/6 or a mixture thereof.
A method for producing a composite according to any one of items 1 to 15. Ca ₁₀ (PO ₄ ) ₆ Zm where Z is selected from one or more of OH, CO ₃ , F, and Cl, and m is a number satisfying the valence. 17 The fiber material is short fiber, long fiber, fiber yarn,
17. A method for producing a composite according to any one of claims 11 to 16, which is in the form of fiber bundles, wool-like fibers, non-woven fabrics and/or woven fabrics. 18 The apatite according to claims 11 to 17, wherein the apatite is a hydroxyapatite containing essentially only hydroxyl groups and/or a hydroxyapatite in which the hydroxyl group is substituted with a small amount of CO ₃ group. A method for making any complex. 19 The fiber material is carbon, silicon carbide, mullite,
9. The composite of claim 8 selected from silica, alumina, apatite glass, and silicon titanide fibrous materials. 20. The method for producing a composite according to any one of claims 1 to 19, wherein the composite is a bioceramic. 21. The method for producing a composite according to any one of claims 1 to 20, wherein the firing temperature is less than 700°C.