JP2001340365A - Biogenic implant and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a biogenic implant in which an metallic body and a ceramic body have sufficient joining strengths in its used environment in an organism and which has no toxicity and, accordingly, can be used stably for a long period and a method of manufacturing the implant. SOLUTION: In the method of manufacturing biogenic implant comprising a step of joining the ceramic body and metallic body to each other by heating the bodies while the metallic body is placed on the surface of the ceramic body, the metallic body is placed on an intermediate layer composed of the same metallic material as that of the metallic body after the layer is arranged on the surface of the ceramic body and the ceramic body and metallic body are joined to each other by heating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an artificial bone and an artificial joint for orthopedic surgery, which are used in a treatment for repairing a bone function or a joint function of a limb due to a disease or a disaster. Alternatively, the present invention relates to a biological implant material constituting an artificial root and the like used for restoring a tooth lost due to aging, disease, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the development of implantology has been remarkable, and in particular, in the field of orthopedics, artificial joints for restoring lost joint functions have been widely used. In the field, artificial dental roots are in the spotlight.

[0003] Intraosseous implants such as artificial bones, artificial joints and artificial tooth roots require high strength, and therefore, stainless steel, cobalt chromium alloy, titanium alloy, etc. are used for these. However, ceramic materials such as alumina and zirconia, which are excellent in corrosion resistance and sliding characteristics in a living body, have been widely used.

As a biological implant combining a metal body and a ceramic body in order to take advantage of such materials, there is an artificial hip joint having a ceramic head and a stem made of ceramic. This artificial hip joint is obtained by pressing and fitting a ceramic head cap having a corresponding tapered hole onto a tapered pin-shaped stem neck of a metal stem.

[0005] However, the combination of the metal body and the ceramic body is generally limited to the configuration of the femoral member, and there is no other practical example. That is, if a metal body and a ceramic body are mechanically engaged to form a composite, there are many restrictions on the shape, and such a structure cannot be generalized.

[0006] Conventionally, the following various methods have been known as metallurgical joining methods of metal and ceramic. A mixture of a powder mainly composed of Mo-Ti-W and an organic binder was applied to the joint surface of the ceramic body,
Heat to 1700 ° C. to react. This is a method usually called metallizing. Next, after performing Ni plating on the metallizing layer, a metal body (for example, Cu) is joined to the Ni plating layer by Pb-Sn based solder or the like. Such a joining method is used in an electronic component to form a ceramic body as an insulator and a C body as a conductor.
It is often used when joining u members. A method of joining a metal body and a ceramic body using an alloy mainly composed of a noble metal such as Au or Pt, that is, a metal having a low affinity for oxygen. Ti, Ni, Zr on the joint between metal and ceramic
A method in which an active metal such as, for example, or an active metal hydride that is converted into an active metal by heat treatment is interposed, and then joined at high temperature and high pressure. A method in which a laminate of a titanium foil and a nickel foil is inserted between a metal body and a ceramic body and heated in a vacuum or in an inert gas atmosphere.

[0007] As described above, there are many joining techniques for a metal body and a ceramic body in other technical fields. However, in any of the conventional methods, when the joining technique is diverted to a living body implant material, safety in a living body is required. There is a problem with sex.

[0008] In other words, in these joining methods, a joining surface is formed by eutectic bonding of different metal materials, and such a joining surface is corroded by vigorous electrolytic corrosion in a living body environment. (Galvanic corrosion). As a result, the living body is harmed, such as an allergic reaction.

Some of the metals used are dangerous to living organisms (for example, Ni and the like have carcinogenicity), and these conventional joining methods have never been used for living implant materials. Was.

In view of the above-mentioned problems of the prior art, the present invention has a metal body and a ceramic body having sufficient bonding strength in a use environment in a living body, and has no toxicity to a living body.
Therefore, an object is to provide a biological implant material that can be used stably for a long period of time and a method for producing the same.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to a process of joining a ceramic body and a metal body by heating the metal body with the metal body placed on the surface of the ceramic body. In the method for producing a living body implant material, comprising: placing an intermediate layer made of the same metal material as the metal body on the surface of the ceramic body; placing the metal body on the intermediate layer; It is characterized in that the metal body is heated and joined.

According to this configuration, the intermediate layer causes a plastic flow in the heat bonding step, and the degree of adhesion between the intermediate layer and the metal layer increases, so that the metal body and the ceramic body can be used in vivo through the intermediate layer. A biological implant having a sufficient bonding strength in an environment can be obtained.

Further, since the intermediate layer and the metal body are made of the same metal material, there is no corrosion due to electrolytic corrosion which occurs when a combination of different metals is used. Therefore, it is possible to provide a biological implant that can be used stably in vivo for a long period of time.

Further, in the biological implant material of the present invention, in a biological implant member in which a metal body is joined to a ceramic body, an intermediate layer made of the same metal material as the metal body is provided between the ceramic body and the metal body. It is characterized by having.

[0015]

Embodiments of the present invention will be described below. The bioimplant material of the present invention has a structure in which an intermediate layer is provided between the ceramic body and the metal body in a bioimplant member obtained by bonding a metal body to a ceramic body. As the above ceramic body,
Oxide ceramic (alumina, zirconia, titania), nitride ceramic (silicon nitride, titanium nitride, aluminum nitride) or carbide ceramic (silicon carbide)
Alternatively, a mixed ceramic with improved material strength, such as alumina-dispersed zirconia or titania-dispersed alumina, can be used. Further, as the above-mentioned metal body, a metal which is well-adapted to the living body and has no toxicity, for example, one selected from titanium, tantalum, tungsten, zirconium, molybdenum, niobium, titanium alloy, cobalt chromium alloy, and stainless steel Alternatively, two or more kinds can be used.

[0016] The metal body may be a porous member. For example, as described in JP-A-9-173434, a structure formed by laminating a porous metal plate, a structure obtained by compression-molding a mesh formed by knitting metal wires, and firing a metal bead. A structure or the like obtained by mutual fixing by knotting can be used. By arranging such a structure on the surface of the ceramic body, bones can grow and enter into the pores, and a direct connection with the bone can be obtained, and a surface structure with high mechanical strength can be obtained. be able to. With such a structure, it is possible to obtain an excellent bioimplant material utilizing the good slidability of the ceramic, the good bonding of the metal body to the bone, and the durability due to its high strength.

It is preferable to use zirconia as a ceramic body and titanium as a metal body as a material of the above-mentioned living body implant material. According to this combination, since the respective thermal expansion coefficients are close to each other, it is possible to prevent problems such as generation of minute cracks in the ceramic body at the time of heat bonding. The intermediate layer is made of the same metal material as the metal body. For example, when the metal body is titanium, the intermediate layer is made of titanium, and when the metal body is a titanium alloy, the intermediate layer is made of a titanium alloy. As described above, since the intermediate layer is made of the same metal material as the metal body, the bioimplant material of the present invention does not cause corrosion due to electrolytic corrosion that occurs in the case of a combination of different metals even in a living body environment.

As a method of forming the intermediate layer, a coating means can be used. In this case, it is preferable to use a low thermal shock coating method. Here, the low thermal shock resistance means that the thermal shock is not applied to the ceramic body when forming the coating layer, or the stress due to the cooling shrinkage of the coating layer when coating the ceramic body. The case where no impact is given. As such a low thermal shock coating method, a PVD method such as vacuum evaporation, ion beam evaporation, sputtering, ion plating, and dynamic mixing method, and a wet coating method such as electroplating and electroless plating can be used.

Since the intermediate layer formed by coating by the PVD method has a good plastic flow action due to the fine crystals formed, a large bonding strength can be obtained. In addition, production costs can be reduced by a large amount of processing. In particular, these advantages are remarkable in the sputtering and the ion plating method.

Further, as the intermediate layer, a foil of the same metal material as the metal body can be used. In this case, the intermediate layer of the metal foil is placed on the surface of the ceramic body before the heat bonding step described later. As an advantage of using the intermediate layer of the metal foil, since a coating operation is not required, the operation is simple and the cost is low.

Although the thickness of the intermediate layer varies depending on the material used and the coating method, the thickness of the intermediate layer is preferably from 0.005 mm to 0.1 mm.
When the thickness is less than 0.005 mm, the thickness is too small compared to the size of the unevenness of the contact surface between the ceramic substrate and the metal body, so that the effect of increasing the contact area even by the plastic flow of the intermediate layer in the heating joining process is effective. I can't expect much. On the other hand, if the thickness exceeds 0.1 mm, there is a possibility that intralayer destruction occurs in the intermediate layer.

In the implant of the present invention, after the intermediate layer is disposed on the surface of the ceramic body, the ceramic body and the metal body are joined by heating while the metal body is placed on the intermediate layer. Prepared by In the heat bonding step, the ceramic body and the metal body are heated at a predetermined temperature to thereby strongly bond the ceramic body and the intermediate layer, and the intermediate layer and the metal body. That is, in the heat bonding step, at the interface between the ceramic body and the intermediate layer, both elements are diffused to the other party and both are bonded. On the other hand, at the interface between the intermediate layer and the metal body, both metal atoms are diffused to the other party and they are joined.

Further, in the heating bonding step, the intermediate layer causes a plastic flow, and as a result, the contact area between the intermediate layer and the metal body increases. Thereby, the bonding strength between the intermediate layer and the metal body is sufficiently large.

When titanium is used for the intermediate layer, titanium has a high affinity for oxygen, and diffusion of oxygen from the zirconia side to the intermediate layer and the metal occurs when the ceramic and the metal are joined by heating. As a result, a strong bonding strength between the ceramic body and the metal body can be obtained. Such oxygen diffusion phenomenon,
It is also found in other oxide-based ceramics. For example, even with a combination of alumina and titanium, a high bonding strength between a ceramic body and a metal body can be obtained, though it is inferior to the combination of zirconia and titanium.

The heating temperature varies depending on the combination of materials. In the case of zirconia and titanium, the heating temperature is about 1000.
C was optimal.

In the heat bonding step, the heat treatment is performed for 1
It is preferable that the load be applied in a state where a load of 1 g to 100 g per square mm is applied to the living body implant material. Under a load condition of less than 1 g, a sufficient plastic flow of the intermediate layer cannot be obtained, resulting in a decrease in adhesion. On the other hand, under a load condition exceeding 100 g, the plastic flow is too large, and there is a possibility that a portion where the metal body and the ceramic body directly contact each other may occur, and further, the metal body may be deformed and crushed.

In the biological implant material of the present invention, the intermediate layer may be formed after ions of the metal material and the metal material constituting the intermediate layer are implanted in the ceramic body in advance. By forming in this manner, it is possible to improve the adhesion between the ceramic body and the intermediate layer. For example, if titanium is previously injected into the surface of a ceramic body made of alumina, the adhesion strength can be significantly improved when titanium is used as the intermediate layer.

Further, between the intermediate layer and the ceramic body,
A composite layer including a metal material forming the intermediate layer and a ceramic forming the ceramic body may be provided in which the composition ratio thereof is changed obliquely along the thickness direction of the layer. For example,
In the case of a combination of a ceramic body of titanium nitride and a metal body of pure titanium, by forming a composite gradient layer of zirconia and titanium in which the content of zirconia gradually increases toward the ceramic body between the intermediate layer and the ceramic body. Thus, high adhesion between the intermediate layer and the ceramic body can be obtained.

The composite layer and the intermediate layer can be manufactured in a continuous process. For example, in the ion plating method, first flow a large amount of nitrogen gas, coat titanium nitride on the ceramic body, gradually reduce the amount of nitrogen gas to change the composition of the mixed layer of titanium nitride and titanium, Finally, the nitrogen gas is stopped to form an intermediate layer made of titanium.

[0030]

The present invention will be described below in more detail with reference to examples.

[0031] Example diameter 17 mm, after degreasing the zirconia ceramic disc having a thickness of 5 mm, on one side of the diameter 17 mm, was coated titanium thickness 10μm by a sputtering method, a porous thick 200μm same diameter Ten layers of pure titanium thin plates (effective diameter of through-holes: 300 μm, hole pitch: 500 μm) were laminated, and subjected to diffusion bonding at 1000 ° C. under a load of 10 g per 1 mm 2 to produce test specimens for experiments. Evaluation items are cross-sectional analysis and adhesion strength test. In the cross-sectional analysis, the test piece was cut and polished after embedding in a resin, and the cross section of the test piece was observed with a metallographic microscope (400-fold magnification). On the other hand, the adhesion strength test was performed in accordance with JIS H8666 (ceramic spraying test method). Both sides of each test piece were bonded to a test jig with an epoxy-based adhesive, and a load was applied using an Instron type tensile tester at a pull rate of 1 mm / min until the test piece broke, and the breaking strength was measured. did. Confirmation of the fracture site of each test piece was performed visually and by observation with an optical microscope. In carrying out this test, a test piece without a sputtering layer was also manufactured as a comparative example, and comparative evaluation was performed.

Table 1 shows the results of this test.

[0033]

[Table 1]

As a result of the test, in the comparative example group, the adhesive strength was significantly low, and almost no bonding between the zirconia substrate and the metal porous layer was recognized in the cross-sectional analysis. On the other hand, in the test piece group of the present invention, it is generally said that the bioimplant material to be implanted in the bone needs to have a bonding strength of 28 MPa or more, but a high adhesiveness of 45 MPa was obtained.
In the cross-sectional analysis, diffusion bonding between the sputtering layer and the porous metal layer accompanied by deformation of the sputtering layer due to plastic flow was observed.

[0035]

As described above, according to the manufacturing method of the present invention, the ceramic body and the metal body are heated by heating the metal body with the metal body mounted on the surface of the ceramic body. In the method for manufacturing a biological implant material including a joining step, after arranging an intermediate layer made of the same metal material as the metal body on the surface of the ceramic body, placing the metal body on the intermediate layer to form the ceramic Since the body and the metal body are joined by heating, the intermediate layer causes a plastic flow in the heating joining step, and the joining strength between the ceramic body and the metal body increases.

Therefore, it is possible to obtain a living body implant having a sufficient bonding strength between the metal body and the ceramic body in a use environment in a living body.

Further, since the interface between the intermediate layer and the metal body is made of the same metal material or the same kind of metal material, the above-mentioned biological implant does not cause corrosion due to electrolytic corrosion which occurs when a combination of different metals is used. Therefore, it can be used stably in vivo for a long time.

According to the bioimplant material of the present invention, in the bioimplant material in which a metal body is joined to a ceramic body, an intermediate layer made of the same metal material as the metal body is provided between the ceramic body and the metal body. Is provided, the bonding strength between the ceramic body and the metal body is increased.

Therefore, it is possible for the metal body and the ceramic body to have a sufficient bonding strength in an in-vivo use environment.

Further, since the interface between the intermediate layer and the metal body is made of the same metal material or the same kind of metal material, corrosion due to electrolytic corrosion which occurs in the case of a combination of different metals does not occur. Therefore, it can be used stably in vivo for a long time.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C23C 14/18 C23C 14/18 (72) Inventor Junji Ikeda 10-1 Kawai, Gamo-cho, Gamo-gun, Shiga Prefecture Inside the Gamo block of the Cera Corporation Shiga Factory (72) Hiroyuki Kitano Inventor, 10-10 Kawai, Gamo-cho, Gamo-gun, Shiga Prefecture Inside the Gamo Block of the Kyocera Corporation Shiga Factory (72) Inventor Shingo Masuda No. 10 at Kawai F-term in Gamo block of Shiga Plant of Kyocera Corporation 4C059 AA02 AA08 4C081 AB03 AB05 AB06 AC03 BA02 BA15 CF121 CG02 CG03 CG04 CG05 CG06 CG08 DC02 EA06 4C097 AA02 AA11 AA30 BB01 CC03 DD03 BB21 BE04 BF31 BF41 BF42 BG03 BH13 4K029 AA04 AA24 BA06 BA11 BA17 BD00 CA05

Claims (7)

[Claims] 1. A method for manufacturing a living body implant material, comprising a step of joining a ceramic body and a metal body by heating the metal body with the metal body placed on the surface of the ceramic body. After disposing an intermediate layer made of the same metal material as the metal body on the surface, the metal body is placed on the intermediate layer, and the ceramic body and the metal body are joined by heating. Manufacturing method of implant material. 2. The method according to claim 1, wherein the intermediate layer is formed on the surface of the ceramic body by P
The method for producing a biological implant material according to claim 1, wherein the material is formed by a VD method. 3. The method according to claim 1, wherein the intermediate layer is a metal foil. 4. The intermediate layer has a thickness of 0.005 to 0.1 m.
The method for producing a biological implant material according to claim 1, wherein m is m. 5. The method according to claim 1, wherein the metal body is made of one or more selected from titanium, tantalum, tungsten, zirconium, molybdenum, niobium, a titanium alloy, a cobalt-chromium alloy, and stainless steel. Item 10. A method for producing a biological implant material according to Item 1. 6. The ceramic body is made of zirconia,
The method according to claim 1, wherein the metal body is made of titanium or a titanium alloy. 7. A biological implant member in which a metal body is joined to a ceramic body, wherein an intermediate layer made of the same metal material as the metal body is provided between the ceramic body and the metal body. Wood.