JP2001089227A - Porous calcium phosphate compound/metal composite sintered compact and its production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a porous calcium phosphate compound/metal composite sintered compact having superior biocompatibility and high strength and not causing the falling of calcium phosphate compound particles from the surface in a short time at a low cost. SOLUTION: The composite sintered compact comprising large and small particle diameter porous calcium phosphate compound particles and a metal has a surface layer containing large and small particle diameter porous calcium phosphate compound particles in at least part of the surface and part of the large and small particle diameter porous calcium phosphate compound particles are exposed to the surface by sintering by a discharge plasma sintering method. The large and small particle diameter porous calcium phosphate compound particles do not fall from the surface of composite sintered compact and the sintered compact has high strength.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a composite sintered body of porous calcium phosphate-based compound particles / metals having large and small particle diameters in which porous calcium phosphate-based compound particles having high biocompatibility are exposed on the surface, And a method for producing such a composite sintered body in a short time and at low cost.

[0002]

2. Description of the Related Art Calcium phosphate compounds (for example, hydroxyapatite) have excellent biocompatibility and are used as biomaterials such as artificial dental roots, bone reinforcing materials, and dental cement. However, calcium phosphate compounds are inferior in mechanical strength, particularly in bending strength, and cannot be used for parts requiring high strength. Therefore, metal materials having no harm to human body, such as titanium and stainless steel, are widely used for artificial roots and bone reinforcing materials. However, from the viewpoint of biocompatibility, calcium phosphate compounds are far superior, and it is desired to use calcium phosphate compounds, especially hydroxyapatite.

Under the circumstances described above, attempts have been made to combine a calcium phosphate compound with a glass material or a metal material, and some of them have already been put into practical use. However, in the case of composite with a glass material, there is a problem that glass elutes in a living body over time.

A composite material of a calcium phosphate compound and a metal material is generally obtained by embedding calcium phosphate compound particles in a metal frame or sintering a mixture of a metal powder and a calcium phosphate compound powder. Can be However, in the former case, there is a possibility that the displacement of the calcium phosphate compound may occur in the living body. In the latter case, the calcium phosphate-based compound powder has a low porosity and a small particle size, and thus has a disadvantage that the calcium phosphate-based compound particles exposed on the surface of the composite sintered body easily fall off.

Accordingly, an object of the present invention is to provide a composite sintered body of porous calcium phosphate compound particles and a metal,
An object of the present invention is to provide a material having excellent biocompatibility and high strength, in which calcium phosphate compound particles do not fall off the surface, and a method for producing such a composite sintered body in a short time and at low cost.

[0006]

Means for Solving the Problems In view of the above problems, as a result of intensive studies, the present inventors have found that at least the surface layer of the calcium phosphate compound powder / metal powder to be sintered has a large particle size and a small particle size porous material. The presence of porous calcium phosphate-based compound powder and the use of a porous calcium phosphate-based compound powder having a large particle diameter that has been pre-fired at a temperature equal to or higher than the sintering start temperature allow the porous calcium phosphate-based compound particles to have a surface The present inventors have discovered that a composite sintered body that is exposed so as not to fall off from the steel can be obtained, and the present invention has been completed.

That is, the composite sintered body of porous calcium phosphate compound particles and metal of the present invention has a surface layer containing large and small particle size porous calcium phosphate compound particles on at least a part of the surface. And the porous calcium phosphate compound particles having the large particle diameter and the small particle diameter are partially exposed on the surface.

[0008] A preferred example of the composite sintered body of the present invention is a porous calcium phosphate compound particle having a large particle size and a small particle size, a surface layer composed of metal, and a calcium phosphate compound particle having substantially a metal and a small particle size. And an inner layer consisting of (Sum of exposed areas of porous calcium phosphate compound particles having large and small particle diameters) / (Surface area of surface layer containing porous calcium phosphate compound particles having large and small particle diameters) (area ratio) Is preferably 5 to 70%.

The large-sized porous calcium phosphate compound particles contained in the composite sintered body have an average particle size of 0.5 to 10 mm,
It preferably has a porosity of 20-70%. In addition, the pores of the large-diameter porous calcium phosphate compound particles are at least partially penetrated by metal, so that the large-diameter porous calcium phosphate compound particles are firmly bonded to the metal phase. It is preferable that the size is large.

The porous calcium phosphate compound particles having a small particle diameter contained in the composite sintered body preferably have an average particle diameter of 10 to 200 μm and a porosity of 70% or less.

The metals used in the composite sintered body of the present invention include Ti, Cr, Fe, Co, Cu, Mo, Ag, Au, Pd, Pt, Al and
It is preferably a metal selected from the group consisting of Ni or an alloy thereof. Further, the weight ratio of the porous calcium phosphate compound particles having a large particle diameter and a small particle diameter to the metal in the surface layer is 1%.
/ 20 to ４ is preferred. Further, the weight ratio of the porous calcium phosphate compound particles having a small particle diameter to the metal in the inner layer is preferably 1/40 to 1/5.

Further, the method of the present invention for producing a composite sintered body of a large particle size and a small particle size porous calcium phosphate compound particles and a metal is characterized in that the large particle size calcium phosphate compound powder is heated to a temperature not lower than the sintering start temperature. By pre-baking at the temperature of the above, to produce a porous calcium phosphate compound powder of large particle size,
The porous calcium phosphate compound powder having the large particle size and the small particle size and the metal powder are coated so that the porous calcium phosphate compound compound having the large particle size and the small particle size exist in at least a part of the surface layer. It is characterized in that a sintered powder is produced and the powder to be sintered is sintered under pressure.

In the method of the present invention, it is preferable that the pre-calcining temperature of the calcium phosphate compound powder having a large particle diameter is 700 to 1300 ° C. It is preferable to use a spark plasma sintering method as the pressure sintering method. Preferably, the sintering temperature is 500 to 1300 ° C., and the time for maintaining the sintering temperature is 5 to 30 minutes.

The porous calcium phosphate compound powder having a large particle diameter used for producing the composite sintered body of the present invention is 0.5 to 10 mm.
Having an average particle size of 20% and 70% porosity.
It is preferably of a size such that the metal at least partially penetrates it and is strongly bonded to the metal phase. The porous calcium phosphate compound particles having a small particle diameter contained in the composite sintered body preferably have an average particle diameter of 10 to 200 μm and a porosity of 70% or less. In addition, metal powder is 1-50
It preferably has an average particle size of 0 μm.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The composite sintered body of the present invention comprising porous calcium phosphate compound particles having a large particle diameter and a small particle diameter and a metal and a method for producing the same will be described in detail below.

[1] Method for producing composite sintered body (A) Production of porous calcium phosphate compound powder having large and small particle diameters (1) Production of foamed calcium phosphate compound powder Porous calcium phosphate compound powder To make the body,
First, porous granules of calcium phosphate compound powder are produced. Calcium phosphate compounds that can be used in the present invention
The molar ratio of Ca / P is 1.5 to 2.0, specifically, apatites such as hydroxyapatite and fluorapatite, tricalcium phosphate, tetracalcium phosphate and the like, or a mixture of two or more thereof.

The granules can be produced by a known method, but it is preferable to use a method described in JP-A-3-252304, a spray-dry granulation method, or the like. The method for producing granules described in JP-A-3-252304 is to thicken or gel after foaming a slurry or a flowable gel containing a calcium phosphate compound powder and a polymer substance, and forming the resulting foam molded article. If necessary, calcine and pulverize, or after thickening or gelling a slurry or a fluid gel containing a calcium phosphate compound powder, a polymer substance and a foaming agent, and foaming by heating, It is a method of calcining and pulverizing accordingly. Hereinafter, each will be described in detail.

Method A polymer having a mean particle size of 1 to 50 is added to a dispersion liquid (which may be a solution, a colloid solution or a suspension) or a fluid gel.
A calcium phosphate-based compound powder of μm is mixed and vigorously stirred to embrace air to obtain a slurry or a fluid gel containing many fine bubbles. The size and amount of bubbles in the foamed slurry or fluid gel can be controlled by stirring. The solid content concentration of the slurry or the fluid gel is 7 to 65% by weight of the calcium phosphate compound powder and 100% by weight, assuming that the whole is 100% by weight.
It is preferably from 1 to 10% by weight. The foamed slurry or fluid gel is poured into a mold and dried. Thus, a high-strength foam molded article having substantially spherical cells can be obtained.

The dispersion or fluid gel of the polymer substance may be stirred and foamed before mixing with the calcium phosphate compound powder, or the powdery polymer substance and the calcium phosphate compound powder may be mixed. After mixing, a dispersion medium may be added to form a slurry, which may be stirred and foamed.

Since water is generally used as a dispersion medium for the calcium phosphate compound powder, the polymer substance is preferably water-soluble, but when an organic solvent is used, it is dissolved in the solvent. You may. Examples of such high molecular substances include cellulose derivatives such as methylcellulose and carboxymethylcellulose, polysaccharides such as curdlan, and polymers such as polyvinyl alcohol, polyacrylic acid, polyacrylamide, and polyvinylpyrrolidone.

Method This method is the same as the method, except that a blowing agent is used instead of air entrapment. Therefore, the calcium phosphate compound powder and the polymer used in this method are as described above.

The calcium phosphate compound powder, a foaming agent and a polymer substance are kneaded in a dispersion medium to form a slurry or a fluid gel. As the foaming agent, hydrogen peroxide, ovalbumin and the like are used. A desired porosity can be obtained by changing the concentration or the amount of the foaming agent. For example, when using hydrogen peroxide alone, the hydrogen peroxide is 0.01 to 0.
It is sufficient to add it to be present in an amount of 5% by weight.

The amount of the polymer substance used in this method may be smaller than that in the above method, and may be about 0.0001 to 2.0% by weight based on 100% by weight of the whole slurry or fluid gel.
For example, in the case of methylcellulose, it may be 0.001 to 1.5% by weight, and in the case of polyvinyl alcohol (molecular weight 2000)
~ 0.3% by weight, for polyacrylic acid 0.0001 ~ 0.
001% by weight, pectin 0.005 to 0.1% by weight
Is good.

The obtained slurry or fluid gel is mixed with 70 to 12
Heat to 0 ° C and dry with foaming. In the early stage of the heating step, foaming occurs, and the bubbles are embraced in the thickened slurry as they are, so that a plurality of bubbles do not combine or be released. Therefore, a foam molded article in which fine bubbles are uniformly dispersed can be obtained.

(2) Firing (2-1) Porous Calcium Phosphate-Based Compound Powder with Small Particle Size In order to remove moisture and impurities in the foamed molded product, it is preferable to calcine the foamed molded product at 700 to 1300 ° C. preferable. If the sintering temperature is lower than 700 ° C., the removal of moisture and impurities becomes insufficient, and if it is higher than 1300 ° C., the calcium phosphate compound is decomposed or deteriorated, which is not preferable.

The firing time (time for maintaining the above firing temperature) is preferably 1 to 10 hours. If the firing time is less than 1 hour, the preliminary firing effect cannot be obtained, and if it exceeds 10 hours, a substantial sintering reaction occurs. A more preferred firing time is 2 to 5 hours. The firing atmosphere is not particularly limited, and is preferably performed in the air for the purpose of preventing the decomposition of the calcium phosphate compound.

It is preferable to pulverize and classify the compact after firing to adjust the particle size to 10 to 200 μm to obtain a calcium phosphate compound powder having a small particle size. If the particle size is larger than 200 μm, the strength of the composite decreases. The lower limit of the particle size is not particularly limited. However, if the particle size is less than 10 μm, only the cost increases, and the accompanying effect cannot be improved.

(2-2) Large Calcium Phosphate Calcium Phosphate Compound Powder Preliminary firing of the calcium phosphate compound foam so that sintering does not substantially proceed during discharge plasma sintering Perform For this purpose, the pre-firing temperature must be equal to or higher than the sintering start temperature. In a preferred embodiment, the pre-firing temperature is between 700 and 1300 ° C. If the pre-sintering temperature is lower than 700 ° C, sintering of the calcium phosphate compound occurs during pressure sintering, crystal grains are coarsened, deformed by pressure, pores are crushed, and their porosity is lost. Do not sufficiently enter the pores. 1300 ℃
If it is higher, decomposition or deterioration of the calcium phosphate compound occurs, which is not preferable. A more preferred pre-firing temperature is 700-1200 ° C.

The pre-firing time (time at which the pre-firing temperature is maintained) is preferably 1 to 10 hours. If the pre-firing time is less than 1 hour, the pre-firing effect cannot be obtained, and
If the time is exceeded, a substantial sintering reaction occurs. A more preferred pre-firing time is 2 to 5 hours. The atmosphere for the preliminary firing is not particularly limited, and is preferably performed in the air for the purpose of preventing the decomposition of the calcium phosphate compound.

After the block of the porous calcium phosphate compound obtained by the preliminary firing is pulverized, it is preferably classified and adjusted to a particle size of 0.5 to 10 mm to obtain a porous calcium phosphate compound powder having a large particle size. . Large particle size of porous calcium phosphate compound powder (granules) is 0.5m
If it is smaller than m, the surface exposed area of the porous calcium phosphate compound particles having a large particle diameter is insufficient, and a sufficient effect of improving biocompatibility cannot be obtained. If the diameter is larger than 10 mm, the distribution of the large-sized porous calcium phosphate-based compound particles in the composite sintered body becomes uneven, and the possibility of crushing of the large-sized porous calcium-phosphate-based compound particles exposed on the surface increases. Is not preferred. More preferably, the particle diameter of the porous calcium phosphate compound powder having a large particle diameter is 1 to
5 mm.

The feature of the composite sintered body of the present invention is that the metal enters the pores of the porous calcium phosphate compound particles, whereby the porous calcium phosphate compound particles adhere firmly to the metal phase and fall off from the surface. That is not to do. In addition, the calcium phosphate compound powder to be added to the metal powder in consideration of the bonding property with bone must be porous, and it is preferable to adjust the porosity and the pore diameter.

The porosity of the calcium phosphate compound powder having a small particle size is preferably 70% or less. If the porosity exceeds 70%, the mechanical strength of the powder itself becomes insufficient, which is not preferable. A more preferred porosity is 10 to 50%. The pores are limited depending on the particle size, but are preferably at least large enough to allow a part of the metal to enter by pressure sintering.

The porosity of the calcium phosphate compound powder having a large particle diameter is preferably 20 to 70%. When the porosity is less than 20%, the metal does not sufficiently enter the pores of the porous calcium phosphate-based compound particles having a large particle diameter, resulting in poor adhesion. On the other hand, if the porosity exceeds 70%, the mechanical strength of the porous calcium phosphate compound powder having a large particle diameter becomes insufficient, which is not preferable. Although the pores vary in size, it is necessary that the pores have at least such a size that a metal can enter by pressure sintering, and preferably have a diameter of 20 to 2000 μm.

(B) Production of Powder to be Sintered The powder to be sintered consisting of a porous calcium phosphate compound powder having a large particle size and a small particle size to be sintered under pressure and a metal powder may be a uniform mixture. In order to obtain good biocompatibility and mechanical strength at the same time, at least a part of the surface is provided with a surface layer containing a porous calcium phosphate compound powder having a large particle size and a small particle size, and other portions are made of metal. It is preferably formed of a powder and a small particle size calcium phosphate compound powder.

As the metal powder, Ti, Cr, Fe, Co, Cu,
Mo, Ag, Au, Pd, Pt, preferably a metal selected from the group consisting of Al and Ni or an alloy thereof, particularly Ti, Fe, Pd
Or an alloy thereof is more preferable. Stainless steel is preferred as the alloy. The metal powder preferably has an average particle size of 1 to 500 μm. The average particle size of the metal powder is 50
If it is more than 0 μm, the relative density of the mixture with the large particle size and the small particle size porous calcium phosphate compound powder is too low,
Porous calcium phosphate compound powders having a large particle diameter and a small particle diameter are insufficiently penetrated into the pores. The lower limit of the average particle size of the metal powder is not particularly limited. However, if the average particle size is less than 1 μm, the cost is increased and the filling property is deteriorated, so that the effect cannot be improved.

For example, in order to form a powder having a sandwich structure having a surface layer containing a porous calcium phosphate compound powder having a large particle diameter and a small particle diameter on both sides, a large powder is first placed in a cavity of a molding die. A porous calcium phosphate compound powder having a particle diameter is added (in some cases together with a porous calcium phosphate compound powder having a small particle diameter), and then the calcium phosphate compound powder having a small particle diameter and the metal powder are uniformly mixed. The mixed powder may be added, and finally, a large-sized porous calcium phosphate compound powder (in some cases, together with a small-sized porous calcium phosphate compound powder) may be added. Since the metal powder is finer than the porous calcium phosphate compound powder having a large particle diameter, the metal powder enters between the particles of the porous calcium phosphate compound powder having a large particle diameter, and the calcium phosphate compound having a small particle diameter. Since the compound powder is also exposed to the surface by pressing, the powder to be sintered is [mixed phase (surface layer) of porous calcium phosphate compound powder of large and small particle size + metal powder] / small particle size Mixed phase of calcium phosphate compound powder + metal powder (inner layer) / [mixed phase of porous calcium phosphate compound powder with large and small particle diameter + metal powder (surface layer)] Become.

The powder to be sintered may be a powder formed in a molding die, but may be a green compact from the viewpoint of handleability.
If the green compact is separately manufactured, the sintering step can be shortened. In order to produce a green compact, a die pressing method, a cold isostatic pressing (CIP) method, or the like can be used. When a green compact is used, the relative density may be about 30 to 70%.

(C) Pressure Sintering In the present invention, it is preferable to use a spark plasma sintering method for producing a composite sintered body. Spark plasma sintering is a method in which a powder to be sintered is filled between a pair of dies connected to a power supply, and a current is applied while pressurizing. Since the powder to be sintered filled in the mold is in contact with the powder and has many voids between the particles of the powder to be sintered, the calcium phosphate compound is semiconductive, and the metal powder is conductive. When a voltage is applied to both ends of the mold, a current flows through the powder to be sintered. At this time, sparks occur in the gaps between the particles of the powder to be sintered, and discharge plasma is generated in a vacuum. Therefore, the sintering powder composed of the porous calcium phosphate-based compound powder and the metal powder having the large particle size and the small particle size is rapidly sintered. As described above, the spark plasma sintering method is to produce a composite sintered body utilizing self-heating caused by a discharge phenomenon between particles, and has excellent thermal efficiency,
A high-quality sintered body can be manufactured.

An apparatus for performing spark plasma sintering and an example of a spark plasma sintering method using the same will be described with reference to FIGS. A discharge plasma sintering apparatus 1 shown in FIG. 1 includes a vacuum chamber 6 provided with a vacuum pump 7, a mold 2 disposed therein, and a mold 2 which is moved up and down in the mold 2.
Punches 4a and 4b for pressing the powder 3 to be sintered filled therein,
Rams 5a and 5b for driving the punches 4a and 4b are provided. A thermocouple (not shown) for measuring a sintering temperature is provided in the molding die 2.

Each of the rams 5a and 5b is driven by a pressure driving mechanism 9 to pressurize the sintering powder 3, and is connected to a power supply 8 via a power supply terminal (not shown).
Apply a pulse voltage to 4b. The pulse voltage is preferably DC. The control unit 10 is connected to the pressure driving mechanism 9, the power supply 8, the vacuum pump 7 and the thermocouple, and controls the sintering pressure and the sintering temperature in the mold 2, the degree of vacuum in the vacuum chamber 6, and the like.

FIG. 2 is an enlarged view showing details of the molding die 2 and the punches 4a and 4b to be loaded in the spark plasma sintering apparatus 1. The molding die 2 has a ring-shaped integral structure, and has a cavity 2a having a cylindrical, oval, rectangular or other cross section. From the viewpoint of conductivity, the mold 2 is preferably formed of a conductive material such as carbon, various metals, and a cemented carbide, and among them, carbon is preferable because of low cost.

It is preferable to provide conductive carbon paper 11 on the inner peripheral surface of the mold 2. The carbon paper 11 serves as a cushioning material for preventing the sintered body from sticking to the inner wall surface of the molding die 2 and also prevents a resistance from being generated when a voltage is applied to the powder 3 to be sintered. Note that carbon may adhere to the surface of the sintered body after sintering, but can be easily removed by heating in the air, so that there is no influence of carbon on the sintered body.

Each punch 4a, 4b is a cavity of the mold 2.
It has the same slightly smaller cross-sectional shape as the cavity 2a so as to move up and down in the interior 2a. Each punch 4a, 4b is a ram 5a,
Since it is fixed to 5b and has a function of applying a pulse voltage to the powder 3 to be sintered, it is preferably formed of a conductive material such as carbon similarly to the molding die 2. Also each punch 4
It is preferable to provide carbon paper 11 also on the outer peripheral surfaces of a and 4b.

First, the inner surface of the mold 2 is covered with carbon paper 11 in the disassembled state shown in FIG. 3, then the lower punch 4b is inserted into the mold 2, and then the lower alumina molded body 12b is inserted. After the carbon paper 11 is provided on the pressing surface of the alumina molded body 12b, the sintering powder 3 is filled in the cavity 2a.

In the case where the powder 3 to be sintered has a sandwich structure containing porous calcium phosphate compound powders 13 and 15 having large and small particle diameters only on both sides, first, the porous calcium phosphate compound powder 13 having a large particle diameter is used. (Possibly together with the small-sized porous calcium phosphate-based compound powder 15), and further mixed uniformly with the small-sized porous calcium-phosphate-based compound powder 15 and the metal powder 14. Is preferably filled. Since the particle size of the porous calcium phosphate compound powder 13 having a large particle size is much larger than the particle size of the metal powder 14, the metal powder 14 enters between the porous calcium phosphate compound powders 13. Further, the calcium phosphate compound powder having a small particle size is also extruded by pressurization and is exposed on the surface. As a result, a surface layer composed of the porous calcium phosphate compound powders 13 and 15 and the metal powders 14 having the large particle diameter and the small particle diameter is formed.
By adjusting the particle size, porosity and pore size of the porous calcium phosphate compound powder 13 having a large particle size and the particle size of the metal powder 14, or adding the calcium phosphate compound powder 15 having a small particle size By adjusting the particle size, the porous calcium phosphate compound particles 13 'and 15' having a large particle diameter and a small particle diameter exposed on the surface of the composite sintered body can be adjusted to be 5 to 70 area%. Finally, the porous calcium phosphate-based compound powder 13 having a large particle diameter is filled (in some cases together with the porous calcium phosphate-based compound powder 15 having a small particle diameter). The molded body 12a is inserted.

The alumina compacts 12a and 12b act as a cushion and prevent heat from being directly transmitted from the punch, thereby reducing the temperature difference in the sintered body generated during sintering.
Such a temperature difference occurs because, when a large current is applied at the time of rapid temperature rise, the diameter (cross-sectional area) of the punch becomes larger than
When the punch is extremely small, the current density in the punch becomes high, the punch is overheated, and the temperature of the sintered body at the portion in contact with the punch becomes higher than that at the center, and the temperature distribution of the sintered body is not good. This is because it becomes uniform. Alumina molded body 12
The relative density of a and 12b is preferably 70% or more. If the relative density of the alumina compacts 12a and 12b is less than 70%, the strength becomes insufficient and the alumina compacts 12a and 12b are deformed or broken during molding.

After filling, the vacuum chamber 6 is sealed, deaerated by the vacuum pump 7, and kept at a vacuum of about 10 ^-2 Torr. By keeping the inside of the mold 2 in a vacuum state, discharge plasma is generated by application of a pulse voltage.

The pressure drive mechanism 9 is operated by the control unit 10,
At least one of the rams 5a and 5b moves in a direction approaching each other, and the punches 4a and 4b fixed to these press the powder 3 to be sintered. Pressing force by punches 4a and 4b is 100 to 2000kgf /
cm ² is preferable, and 200 to 700 kgf / cm ² is more preferable.
Pressure is difficult to 100 kgf / cm ² less than the densification of the sintered body, also 2,000 kgf / cm be larger than ² improve densification effect corresponding thereto is not obtained, insufficient strength of the mold 2 Only the problem described above occurs.

When a pulse voltage is applied between the punches 4a and 4b from the power supply 8, a current flows through the powder 3 to be sintered between the punches 4a and 4b, and a porous calcium phosphate compound having a large particle size and a small particle size. Sparks are generated in the gaps between the powders 13, 15 and the metal powder 14, generating heat and generating discharge plasma. By these actions, the porous calcium phosphate compound powders 13 and 15 and the metal powder 14 having the large and small particle diameters are heated under pressure and reach the sintering temperature in about 5 to 20 minutes.

The powder to be sintered 3 is heated according to a preset temperature raising program. For this purpose, the temperature of the powder 3 to be sintered is detected by a thermocouple (not shown) provided in the molding die 2, and the output of the thermocouple is input to the control unit 10. The control unit 10 generates a signal for raising the temperature according to the temperature raising program based on the input temperature data, and outputs the signal to the power supply 8. The power supply 8 supplies an appropriate pulse voltage to the rams 5a and 5b in accordance with a command from the control unit 10.

A preferable pulse voltage is formed by an on / off pattern of a DC voltage, and a ratio (t ₁ / t ₀ ) of a duration t _{1 of one} ON state to a duration t _{0 of} OFF state is 1 /.
1 to 12/1, for example, 6/1. When t ₁ / t ₀ is smaller than 1/1, heat generation is insufficient and the sintering time is prolonged. When t ₁ / t ₀ is larger than 12/1, the pulse property is reduced and the energy efficiency is reduced. The pulse voltage can be adjusted to a precision of several volts, and the pulse frequency can be adjusted from 300 Hz to 30 kHz. The voltage and frequency of the pulse are adjusted by the control unit 10 so that the powder 3 to be sintered has a predetermined temperature.

The sintering temperature is preferably from 500 to 1300 ° C., more preferably from 800 to 1200 ° C. If the sintering temperature is lower than 500 ° C., sufficient sintering does not occur, and the strength and toughness of the obtained composite sintered body are insufficient. On the other hand, sintering temperature is 1300 ℃
If it is higher, the calcium phosphate compound will be decomposed.

The sintering time (time for maintaining the sintering temperature) is 5
The time is preferably from 30 to 30 minutes, more preferably from 5 to 15 minutes. If the sintering time is shorter than 5 minutes, sufficient sintering is not performed, and if the sintering time is longer than 30 minutes, crystal grains become coarse, which is not preferable.

After completion of sintering, 500
It is allowed to cool to below ℃, and the mold is opened to take out the composite sintered body. In this way, a composite sintered body 40 of the calcium phosphate compound and the metal having the large and small particle size porous calcium phosphate compound particles 13 ′ and 15 ′ exposed on the surface is obtained. In the as-sintered composite sintered body 40, the porous calcium phosphate compound particles 13 '15' having a large particle size and a small particle size on the surface are provided.
Since the degree of exposure is insufficient, it is preferable to slightly grind the surface. Thereby, the surface exposure degree of the porous calcium phosphate compound particles having a large particle diameter and a small particle diameter is maximized.

[2] Composite Sintered Body The composite sintered body 40 of the present invention has a porous calcium phosphate compound powder 13, 15 having a large particle diameter and a small particle diameter at least on its surface layer.
Has high biocompatibility due to the presence of In addition, when spark plasma sintering is performed, the internal metal powder 14 enters the pores of the porous calcium phosphate compound powder and sinters, so that high adhesion is maintained, and calcium phosphates having large and small particle sizes are maintained. There is no dropping of the system compound particles.

The large and small particle size porous calcium phosphate compound particles contained in the composite sintered body have substantially the same average particle size as the large and small particle size porous calcium phosphate compound powder used. It preferably has a diameter, porosity and pores. That is, the porous calcium phosphate compound particles 13 'having a large particle diameter have an average particle diameter of 0.5 to 10 mm and a porosity of 20 to 70%, and the pores are at least partially filled with metal. Therefore, it is preferable that the size is such that the porous calcium phosphate compound particles having a large particle diameter are firmly bonded to the metal phase.

The porous calcium phosphate compound particles 15 'having a small particle diameter preferably have an average particle diameter of 10 to 200 μm and a porosity of 70% or less. The pores preferably have a size such that the metal can at least partially penetrate therein.

Two preferred embodiments of the composite sintered body of the present invention are shown in FIGS. The composite sintered body 40 of the embodiment shown in FIG. 4A has surface layers 40a, 40a made of a mixture of large and small particle size porous calcium phosphate compound particles 13 ', 15' + metal 14 '. Inner layer 40 composed of metal 14 'inside the metal + porous calcium phosphate compound particles 15' having a small particle size
b. Fig. 4 (b)
Shows a composite sintered body composed entirely of a mixture of porous calcium phosphate compound particles 13 'and 15' having a large particle diameter and a small particle diameter and a metal 14 '.

In the embodiment shown in FIG. 4A, (the sum of the exposed areas of the porous calcium phosphate compound particles 13 'and 15' having a large particle size and a small particle size) / (large particle size and Small particle size porous calcium phosphate compound particles 13 ',
The ratio (area ratio) of the surface layer containing 15 'is 5
Preferably it is ~ 70%. If the area ratio is less than 5%, sufficient biocompatibility cannot be obtained, and if it exceeds 70%, the fixation of the calcium phosphate compound becomes insufficient. A more preferred area ratio is 30 to 50%.

The area ratio is calculated as follows. That is, the upper and lower surfaces of the sample were copied, and the entire area of the copied copy became the surface area of the surface layer containing the large and small-sized porous calcium phosphate compound particles 13 ′ and 15 ′. Is replaced with a white portion (large and small particle size porous calcium phosphate compound particles 13 ',
15 ′) and a black portion (metal 14 ′), and a total of the exposed areas of the porous calcium phosphate compound particles 13 ′ and 15 ′ having a large particle size and a small particle size is derived from the total area of the white portions. Then, the area ratio is calculated from the total of the exposed areas and the surface area.

To obtain such an area ratio, the surface layer
In 40a, the weight ratio of the large and small particle size porous calcium phosphate compound particles 13 ', 15' to the metal 14 'is 1 /
It is preferably from 20 to 1/2, more preferably from 1/10 to 1/5. In addition, as long as the large-sized porous calcium phosphate compound particles 13 'are exposed on the surface,
The thickness of 40a is not limited, and the porous calcium phosphate compound particles 13 'may form a single layer or multiple layers. From a practical viewpoint, the thickness of the surface layer 40a is 1 to 5
mm is fine.

The thickness of the inner layer 40b composed of the metal 14 'and the porous calcium phosphate compound particles 15' having a small particle diameter is not particularly limited as long as sufficient mechanical strength, in particular, bending strength can be obtained. About 1 to 10 mm. Also inner layer
The weight ratio of the porous calcium phosphate compound particles 15 'having a small particle diameter to the metal in 40b is preferably from 1/40 to 1/5, more preferably from 1/20 to 1/5.

FIG. 5 is a composite sintered body in which the porous calcium phosphate compound particles 13 ′ and 15 ′ having large and small particle diameters are exposed.
Forty surfaces are shown schematically. The shape of the porous calcium phosphate compound particles 13 'having a large particle diameter shown in FIG. 5 is exaggerated for easy understanding. Each large-diameter porous calcium phosphate-based compound particle 13 'has a large number of fine pores 13a, and a metal 14' enters into the relatively large pores 13a. With this structure, the large-sized porous calcium phosphate compound particles 13 'are firmly bonded to the metal 14' and do not fall off from the surface.

Small Calcium Phosphate Compound Particle 1
Since 5 ′ is also porous, it is not as large as that of the porous calcium phosphate compound particles 13 ′ having a large particle diameter, but is strongly bonded to the metal 14 ′ that has entered some pores, so that the Never fall off. In addition, if the small particle size calcium phosphate compound powder 15 fired at a temperature lower than the sintering start temperature is used, the metal powder 14 and the small particle size calcium phosphate compound powder 15 are strongly bonded to each other by plasma sintering. Since the particles are consolidated, the calcium phosphate-based compound particles 15 'having a small particle size do not fall off the surface. Further, the surface area of the exposed calcium phosphate compound can be increased by dispersing the calcium phosphate compound particles 15 'having a small particle diameter on the surface, and the area ratio can be easily controlled by changing the amount of the dispersed calcium phosphate compound particles. it can.

If the surface exposure of the porous calcium phosphate compound particles 13 ′ and 15 ′ having a large particle size and a small particle size as sintered is insufficient, the surface may be reduced to 0.05 to 1 mm.
It may be ground to some extent.

[0066]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Example 1 500 g of an aqueous solution containing 1% by weight of methylcellulose
In addition, calcium phosphate compound powder 25 having an average particle size of 10 μm
0 g was added and kneaded well. The obtained foamed slurry was cast into a mold having a depth of 20 cm, molded and dried, and then a hydroxyapatite foam molded article was prepared. A part of the foamed molded body is fired in an air furnace at 700 ° C. for 4 hours, crushed and classified to obtain a small-sized porous hydroxyapatite powder having an average particle diameter of 40 μm (porosity of 60%). Was.
The remainder of the foamed molded article is pre-fired in an air furnace at 1200 ° C. for 2 hours, crushed and classified to obtain a porous hydroxyapatite powder having a large particle diameter of 2.0 to 3.0 mm (porosity of 40%). ) Got. Further, the porous hydroxyapatite powder having a large particle diameter had pores large enough to allow the metal to flow.

A cavity 2a (with an inner surface formed by a carbon mold 2 and a carbon lower punch 4b) of a discharge plasma sintering apparatus 1 (SPS-510L manufactured by Sumitomo Coal Mining Co., Ltd.) shown in FIGS. Alumina molded body 12b (thickness 3 mm, covered with carbon paper 11 having a thickness of 200 μm)
(Relative density 80%) and fill the surface with carbon paper
Covered with 11. 0.25 g of the above-mentioned porous hydroxyapatite powder having a large particle diameter is filled thereon, and 2.50 g of stainless steel SUS316L powder (average particle diameter of 25 μm) and 0.25 g of the above-described small-particle hydroxyapatite powder are further filled thereon. The mixed powder was filled, and 0.25 g of the above-mentioned porous hydroxyapatite powder having the large particle diameter was further filled thereon. After the carbon paper 11 was provided on the sintering powder thus filled, the alumina compact 12a was filled.

The pressure inside the vacuum chamber 6 was reduced to a degree of vacuum of 10 ^-2 Torr, and the carbon upper punch 4a was lowered to apply a pressure of 200 kgf / cm ² from below. From power supply 8, both punches
A pulse voltage was applied between 4a and 4b. Pulse voltage is 4V
T ₁ / t ₀ = 12/2 (33.3 msec./5.55 ms, respectively)
ec.) Thus, the powder to be sintered 3 was heated to 900 ° C. and held for 10 minutes for sintering. Thereafter, the pressing force was released and cooling was performed. After taking out the composite sintered body, the surface is about 0.15mm
Ground to a depth of The shape of the obtained composite sintered body was an oval cross section, having a length of 2.5 cm, a height of 0.48 cm, a width of 0.5 cm, and a radius of an arc at both ends of 0.25 cm. The surface exposure (area ratio) of the porous hydroxyapatite was 41%.

The bending strength of the composite sintered body was measured and found to be 4100 kgf / cm ² . The bending strength was calculated from the following equation from a three-point bending test with a span of 1.7 cm. Strength (kgf / cm ² ) = (3 × P × L) / (2 × a ×
b ² ) P: Breaking load (kgf) L: Span (cm) a: Height of specimen (sintered body) b: Width of specimen (sintered body) (cm)

In order to measure the peel strength of the porous hydroxyapatite particles in the composite sintered body, a peel test for repelling the porous hydroxyapatite particles on the surface with a patterned needle and an ultrasonic cleaning machine (270 W) were used. A peeling test was conducted in which a water washing treatment was performed for a minute. As a result, in any case, peeling or falling off of the porous hydroxyapatite was not recognized,
It was found that the adhesion of the porous hydroxyapatite particles to the metal phase was very good.

Example 2 A foamed slurry obtained in the same manner as in Example 1 was
Was cast into a mold and dried, and then a hydroxyapatite foam molded article was prepared. A part of the foamed molded body is baked in an air furnace at 900 ° C. for 4 hours, crushed and classified to obtain a small-sized porous hydroxyapatite powder having an average particle diameter of 150 μm (porosity of 55%). Obtained. In addition, the remainder of the foam molded body was pre-baked in an air furnace at 1200 ° C. for 4 hours.
By crushing and classification, a porous hydroxyapatite powder having a large particle diameter of 2.0 to 3.0 mm (porosity: 40%) was obtained. Further, the porous hydroxyapatite powder having a large particle diameter had pores large enough to allow the metal to flow.

A cavity 2a formed by a carbon mold 2 and a carbon lower punch 4b of the spark plasma sintering apparatus 1 shown in FIGS. 1 and 2 (the inner surface is covered with carbon paper 11 having a thickness of 200 μm). ) Was filled with an alumina molded body 12 b (thickness: 3 mm, relative density: 80%), and the surface was covered with carbon paper 11. Fill it with 0.20 g of the above-mentioned large-diameter porous hydroxyapatite powder,
Stainless steel SUS316L powder (average particle size 15
0 μm) A mixed powder of 2.50 g and 0.40 g of the hydroxyapatite powder having the above small particle size is filled, and 0.20 g is further filled thereon.
The above-mentioned porous hydroxyapatite powder having a large particle diameter was sequentially filled. After the carbon paper 11 was provided on the sintering powder thus filled, the alumina compact 12a was filled.

Spark plasma sintering was performed in the same manner as in Example 1. The sintering conditions are shown below. Degree of vacuum: 10 ^-2 Torr Pressure: 300 kgf / cm ² Pulse voltage: 4 V, t ₁ / t ₀ = 12/2 (33.3 msec./5.55 msec., Respectively) Sintering temperature and holding time: 1000 ° C., 5 minutes

After the discharge plasma sintering, the pressure was released and cooling was performed. After taking out the composite sintered body, the surface was ground to a depth of about 0.1 mm. The shape of the obtained composite sintered body was an oval cross section, having a length of 2.5 cm, a height of 0.43 cm, a width of 0.5 cm, and a radius of an arc at both ends of 0.25 cm. The surface exposure (area ratio) of the porous hydroxyapatite was 45%.

The flexural strength of the composite sintered body was measured in the same manner as in Example 1, and it was 4000 kgf / cm ² . In addition, peeling and dropping of the porous hydroxyapatite was not observed in the peeling test with a patterned needle and the peeling test by ultrasonic cleaning treatment, and the adhesiveness of the porous hydroxyapatite particles to the metal phase was very good. Do you get it.

Example 3 A foamed slurry obtained in the same manner as in Example 1 was
Was cast into a mold and dried, and then a hydroxyapatite foam molded article was prepared. A part of the foamed molded body is fired in an air furnace at 700 ° C. for 4 hours, crushed and classified to obtain a small-sized porous hydroxyapatite powder having an average particle diameter of 40 μm (porosity of 60%). Was. The remainder of the foamed product is prefired in an air furnace at 1200 ° C. for 2 hours, crushed and classified to obtain a porous hydroxyapatite powder having a large particle size of 1.0 to 2.0 mm (porosity).
50%). Further, the porous hydroxyapatite powder having a large particle diameter had pores large enough to allow the metal to flow.

The cavity 2a formed by the carbon mold 2 and the carbon lower punch 4b of the spark plasma sintering apparatus 1 shown in FIGS. 1 and 2 (the inner surface is covered with carbon paper 11 having a thickness of 200 μm). ) Was filled with an alumina molded body 12 b (thickness: 3 mm, relative density: 80%), and the surface was covered with carbon paper 11. Filled with 0.08 g of the above-mentioned porous hydroxyapatite powder of large particle size, mixed powder of 0.02 g of the above-mentioned small particle size hydroxyapatite powder and 0.50 g of stainless steel SUS316L powder (average particle size of 25 μm) SUS316L powder (average particle size 25μ)
m) 1.50 g of hydroxyapatite powder with a small particle size of 0.20
g of hydroxyapatite powder of small particle size after filling with mixed powder of
Fill mixed powder with 0.50g of powder (average particle size 25μm),
Finally, 0.08 g of the above-mentioned porous hydroxyapatite powder having a large particle size was filled. After the carbon paper 11 is provided on the sintering powder thus filled, the alumina molded body
12a was charged.

Spark plasma sintering was performed in the same manner as in Example 1. The sintering conditions are shown below. Degree of vacuum: 10 ^-2 Torr Pressure: 200 kgf / cm ² Pulse voltage: 4 V, t ₁ / t ₀ = 12/2 (33.3 msec./5.55 msec., Respectively) Sintering temperature and holding time: 900 ° C. for 5 minutes

After the discharge plasma sintering, the pressure was released and cooling was performed. After taking out the composite sintered body, the surface was ground to a depth of about 0.15 mm. The shape of the obtained composite sintered body was an oval cross section, having a length of 2.5 cm, a height of 0.39 cm, a width of 0.5 cm, and a radius of an arc at both ends of 0.25 cm. The surface exposure (area ratio) of the porous hydroxyapatite was 33%.

The flexural strength of the composite sintered body measured in the same manner as in Example 1 was 4600 kgf / cm ² . In addition, peeling and dropping of the porous hydroxyapatite was not observed in the peeling test with a patterned needle and the peeling test by ultrasonic cleaning treatment, and the adhesiveness of the porous hydroxyapatite particles to the metal phase was very good. Do you get it.

Example 4 A foamed slurry obtained in the same manner as in Example 1 was
Was cast into a mold and dried, and then a hydroxyapatite foam molded article was prepared. A part of the foamed molded body is fired in an air furnace at 800 ° C. for 2 hours, crushed and classified to obtain a porous hydroxyapatite powder having a small average particle diameter of 20 μm (porosity: 40%). Was. The remainder of the foamed product is prefired in an air furnace at 1000 ° C. for 2 hours, crushed and classified to obtain a large-diameter porous hydroxyapatite powder having a particle size of 3.0 to 4.0 mm (porosity).
30%). Further, the porous hydroxyapatite powder having a large particle diameter had pores large enough to allow the metal to flow.

A cavity 2a formed by a carbon mold 2 and a carbon lower punch 4b of the spark plasma sintering apparatus 1 shown in FIGS. 1 and 2 (the inner surface is covered with a carbon paper 11 having a thickness of 200 μm). ) Was filled with an alumina molded body 12 b (thickness: 3 mm, relative density: 80%), and the surface was covered with carbon paper 11. Fill it with 0.20 g of the above-mentioned large-diameter porous hydroxyapatite powder,
A mixed powder of 4.50 g of Ag powder (average particle diameter 100 μm) and 0.50 g of the above-mentioned small diameter hydroxyapatite powder is filled thereon, and 0.20 g of the above-mentioned porous hydroxy resin having the large particle diameter is further placed thereon. Apatite powder was sequentially filled. After the carbon paper 11 was provided on the sintering powder thus filled, the alumina compact 12a was filled.

Spark plasma sintering was performed in the same manner as in Example 1. The sintering conditions are shown below. Degree of vacuum: 10 ^-2 Torr Pressure: 300 kgf / cm ² Pulse voltage: 4 V, t ₁ / t ₀ = 12/2 (33.3 msec./5.55 msec., Respectively) Sintering temperature and holding time: 700 ° C., 10 minutes

After the discharge plasma sintering, the pressure was released and cooling was performed. After taking out the composite sintered body, the surface was ground to a depth of about 0.2 mm. The shape of the obtained composite sintered body was an oval cross section, having a length of 2.5 cm, a height of 0.44 cm, a width of 0.5 cm, and a radius of an arc at both ends of 0.25 cm. The surface exposure (area ratio) of the porous hydroxyapatite was 43%.

The bending strength of the composite sintered body was measured in the same manner as in Example 1, and it was 4200 kgf / cm ² . In addition, peeling and dropping of the porous hydroxyapatite was not observed in the peeling test with a patterned needle and the peeling test by ultrasonic cleaning treatment, and the adhesiveness of the porous hydroxyapatite particles to the metal phase was very good. Do you get it. Comparative Example A foamed slurry obtained in the same manner as in Example 1 was 20 cm deep.
Was cast into a mold and dried, and then a hydroxyapatite foam molded article was prepared. Foamed body in atmospheric furnace
By firing at 1200 ° C for 4 hours, crushing and classifying,
A porous hydroxyapatite powder having an average particle size of 0.10 mm (porosity 1% or less) was obtained.

The cavity 2a formed by the carbon mold 2 and the carbon lower punch 4b of the spark plasma sintering apparatus 1 shown in FIGS. 1 and 2 (the inner surface is covered with carbon paper 11 having a thickness of 200 μm). ) Was filled with an alumina molded body 12 b (thickness: 3 mm, relative density: 80%), and the surface was covered with carbon paper 11. Then, 0.20 g of the above hydroxyapatite powder is filled, and on top of that, 2.50 g of stainless steel SUS316L powder (particle size: 2.0 to 3.0 mm)
And 0.20 g of the above-mentioned porous hydroxyapatite powder having a large particle size was further filled thereon. After the carbon paper 11 was provided on the sintering powder thus filled, the alumina compact 12a was filled.

Spark plasma sintering was performed in the same manner as in Example 1. The sintering conditions are shown below. Degree of vacuum: 10 ^-2 Torr Pressure: 200 kgf / cm ² Pulse voltage: 4 V, t ₁ / t ₀ = 12/2 (33.3 msec / 5.55 msec, respectively) Sintering temperature and holding time: 900 ° C, 10 minutes

After discharge plasma sintering, when the pressure was released and cooling was performed, a large amount of hydroxyapatite was dropped from the composite sintered body. Also, when the surface was ground to a depth of about 0.2 mm, some of the hydroxyapatite on the surface fell off. The shape of the obtained composite sintered body was an oval cross section, having a length of 2.5 cm, a height of 0.43 cm, a width of 0.5 cm, and a radius of an arc at both ends of 0.25 cm. The surface exposure (area ratio) of the porous hydroxyapatite was 4%.

The bending strength of the composite sintered body was measured in the same manner as in Example 1, and it was 2300 kgf / cm ² . In both cases of the peeling test using the patterned needle and the peeling test by the ultrasonic cleaning treatment, it was found that hydroxyapatite had fallen off.

[0091]

As described above, in the composite sintered body of the porous calcium phosphate compound particles and the metal powder of the present invention, the calcium phosphate compound particles having a large particle size and a small particle size are exposed on the surface. Since it has high compatibility and has a metal phase, it has high mechanical strength, particularly bending strength. In addition, since the metal has entered the pores of the porous calcium phosphate compound particles having a large particle size and a small particle size on the surface, there is an advantage that the porous calcium phosphate compound particles can be prevented from falling off. The composite sintered body of the present invention having such a structure is suitable for applications such as artificial roots and bone reinforcing materials.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a spark plasma sintering apparatus for carrying out a method of the present invention.

FIG. 2 is a longitudinal sectional view showing a state in which a molding die of the spark plasma sintering apparatus of FIG. 1 is filled with a powder to be sintered.

FIG. 3 is an exploded view showing a forming part of the spark plasma sintering apparatus of FIG.

FIG. 4 is a longitudinal section showing the structure of a composite sintered body 3 of porous calcium phosphate compound particles and metal powder of the present invention, and (a) shows a porous particle having a large particle size and a small particle size on both surface layers. 1 shows a sandwich structure containing calcium phosphate compound particles, and (b) shows a structure entirely containing porous calcium phosphate compound particles.

FIG. 5 is an enlarged view showing large and small particle size porous calcium phosphate compound particles exposed on the surface of the composite sintered body of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Discharge plasma sintering apparatus 2 ... Mold 3 ... Sintered powder 4a, 4b ... Punch 5a, 5b ... Ram 6 ... Vacuum chamber 7 ··· Vacuum pump 8 ··· Power supply 9 ··· Pressure drive mechanism 10 ··· Control unit 11 ··· Carbon paper 12a, 12b ··· Alumina molded body 13 ··· Large particle size porous calcium phosphate compound powder 13 ': Large particle size porous calcium phosphate compound particles 13a ... Pores 14 ... Metal powder 14' ... Metal 15 ...・ Small particle size porous calcium phosphate compound powder 15 ′ ・ ・ ・ Small particle size porous calcium phosphate compound particles 40 ・ ・ ・ ・ Composite sintered body 40a ・ ・ ・ Surface layer 40b ・ ・ ・ Inner layer (metal layer) )

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C01B 25/32 C04B 35/00 SF term (Reference) 4C081 AB03 AB06 BA13 BB04 BB08 BB09 CF011 CF021 CF031 CF041 CG01 CG02 CG03 CG04 CG05 CG07 DA01 DB02 DB03 DB05 DB06 DC13 EA02 EA03 EA04 EA15 4C089 AA06 BA03 BA16 BB01 BB02 BB03 BB04 BB05 BB07 CA04 CA06 CA10 4G030 AA08 AA41 AA61 CA05 CA09 GA23 GA07 4G05 EA04

Claims (16)

[Claims] 1. A composite sintered body of porous calcium phosphate compound particles and a metal, wherein at least a part of the surface has a surface layer containing large and small particle size porous calcium phosphate compound particles, A composite sintered body characterized in that a portion of the large and small particle size porous calcium phosphate compound particles is exposed on the surface. 2. The composite sintered body according to claim 1, wherein
A composite sintered body comprising: a surface layer composed of porous calcium phosphate compound particles having large and small particle diameters and a metal; and an inner layer substantially composed of metal and calcium phosphate compound particles having a small particle diameter. . 3. The composite sintered body according to claim 1, wherein (the total exposed area of the large and small particle size porous calcium phosphate compound particles) / (the large and small particle size). A composite sintered body, characterized in that the ratio (area ratio) of the surface layer containing the porous calcium phosphate compound particles is 5 to 70%. 4. The composite sintered body according to claim 1, wherein said large-sized porous calcium phosphate compound particles have an average particle size of 0.5 to 10 mm and a porosity of 20 to 70%. Having a metal at least partially in the pores of the large-diameter porous calcium phosphate-based compound particles, whereby the large-diameter porous calcium-phosphate-based compound particles are firmly bonded to the metal phase. A composite sintered body characterized in that: 5. The composite sintered body according to claim 1, wherein the porous calcium phosphate compound particles having a small particle diameter have an average particle diameter of 10 to 200 μm and a porosity of 70% or less. A composite sintered body characterized by having: 6. The composite sintered body according to claim 1, wherein the metal is Ti, Cr, Fe, Co, Cu, Mo,
A composite sintered body characterized by being a metal selected from the group consisting of Ag, Au, Pd, Pt, Al and Ni or an alloy thereof. 7. The composite sintered body according to claim 1, wherein a weight ratio of said large particle size and small particle size porous calcium phosphate compound particles to said metal in said surface layer is 1%. / 20 to 1/4. 8. The composite sintered body according to claim 2, wherein a weight ratio of the small-sized porous calcium phosphate compound particles to the metal in the inner layer is 1%.
/ 40 to 1/5. 9. The method for producing a composite sintered body of a porous calcium phosphate compound particle having a large particle size and a small particle size according to claim 1 and a metal, wherein the calcium phosphate compound having a large particle size is used. The compound powder is preliminarily fired at a temperature equal to or higher than the sintering start temperature to produce a porous calcium phosphate compound powder having a large particle diameter, and the large particle diameter and the small particle diameter porous A powder to be sintered is produced from the porous calcium phosphate compound powder having a large particle diameter and a small particle diameter and a metal powder so that the calcium phosphate compound powder is present, and the powder to be sintered is pressure-sintered. A method comprising: 10. The method for producing a composite sintered body according to claim 9, wherein a pre-firing temperature of the large particle size calcium phosphate compound powder is 700 to 1300 ° C. 11. The method for producing a composite sintered body according to claim 9, wherein a spark plasma sintering method is performed as the pressure sintering method. 12. The method for producing a composite sintered body according to claim 9, wherein the surface layer portion of the obtained sintered body is ground, and the large particle size and the small particle size A method characterized by increasing the exposed area of the porous calcium phosphate compound particles. 13. The method for producing a composite sintered body according to any one of claims 9 to 12, wherein the porous calcium phosphate compound powder having a large particle diameter has an average particle diameter of 0.5 to 10 mm and a particle diameter of 20 to 10.
A method having a porosity of 70%, wherein at least a part of the pores of the porous calcium phosphate-based compound powder having a large particle diameter has a size allowing a metal to enter. 14. The method for producing a composite sintered body according to claim 9, wherein the porous calcium phosphate compound powder having a small particle diameter has an average particle diameter of 10 to 200 μm and a particle diameter of 70 to 70 μm.
% Or less porosity. 15. The method for producing a composite sintered body according to claim 9, wherein the metal powder is 1 to 500 μm.
A method characterized by having an average particle size of 16. The method for producing a composite sintered body according to claim 9, wherein the sintering temperature is 500 to 1300 ° C., and the time for maintaining the sintering temperature is 5 to 30 minutes. A method comprising: