JPH0526501B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a medical implant used in the medical and dental fields. (Prior art) Titanium or titanium alloy implants are already widely used in the medical field and have excellent corrosion resistance.
It also has the excellent features of high biocompatibility and low risk of false negative effects. However, even though titanium-based implant materials have such excellent features, if they are left in the body for a long time,
Due to corrosion and frictional corrosion caused by tissue fluids and body fluids, the parts that come into contact with the implant and the entire surface of the implant are subject to extremely strong corrosive and destructive effects, resulting in various defects and inconveniences. In order to eliminate such drawbacks, many proposals have been made to improve the implant material by surface treatment. For example, Unexamined Japanese Patent Publication 1973-
As seen in No. 24429, the implant aims to improve corrosion resistance and wear resistance by forming metal oxides, nitrides, carbides, etc. on the surface of the implant using known methods. (Problems to be Solved by the Present Invention) However, when forming the above-mentioned surface layer directly on a titanium-based implant material, for example, a TiO ₂ oxide layer is formed by a known method of anodic oxidation. Although these have excellent adhesion, the thickness of the coating layer is usually less than 1 μm;
It could not be said that the wear resistance was sufficient. On the other hand, products with a nitride or carbide surface layer have excellent wear resistance due to their high surface height, and also have advantages such as good adhesion and good throwing power when used with the ion plating method. However, on the other hand, it was difficult to uniformly control the structure of the formed layer, there were problems with corrosion resistance, and there were concerns about biotoxicity. Therefore, the object of the present invention is to provide a titanium-based implant having a coating layer that is excellent in corrosion resistance, has no biotoxicity, has good adhesion, and is comparable in terms of wear resistance. (Means for solving the problem) As a result of various experiments in view of the above, we first coated the surface of titanium and titanium alloy implants with a thin aluminum film using a known method, and then coated this with an anodic oxidation method. It is characterized by forming a sufficiently thick alumina surface layer with unprecedented abrasion resistance and adhesion by applying a series of known surface treatments such as chemical conversion treatment and pore sealing. Example 1 A was applied to the surface of a pure titanium dental implant to a thickness of 2 to 5 μm by ion plating.
Coated with m. After degreasing and washing with water, it was anodized in a 5% oxalic acid solution at a voltage of 50 V DC for 20 to 30 minutes at 5 to 20°C. The surface of the implant thus obtained was white, and when the cross section of the film was observed under an electron microscope, a typical cell structure was observed. Then, in order to fill the porous layer on the surface, a heat treatment was performed for 20 to 40 minutes in pressurized steam at 3 to 5 atmospheres to seal the pores. A hard alumite layer made of r-type A ₂ O ₃ was formed on the surface of the finally obtained implant. Example 2 An unsealed alloy Ti-6A-4V implant member obtained in the same manner as in Example 1 was mixed with commercially available basic aluminum lactate (containing 10% by weight of A ₂ O ₃ and 15% by weight of lactic acid). After air drying, the sample was immersed in a solution of 300 to 600°C for 1 to 2 hours. The surface of the implant thus obtained was filled with molecularly dispersed ultrafine alumina particles, and had a solid, dense, non-porous amorphous alumina surface. Example 3 The surface of a surgical implant made of titanium alloy Ti-6A-4V was coated with aluminum A to a thickness of 8 to 25 μm using an ion plating device (trade name: IvAdizer). After degreasing and washing with water
Constant current electrolysis was carried out at 0.5 A/dm ² for 1 to 2 hours in a molten salt bath consisting of KHSO ₄ -NaHSO ₄ (2:1 mol). Crystallized α-A ₂ O ₃ in the form of white ground glass was formed on the surface of the implant thus obtained, and showed excellent chemical resistance that was not affected by anything other than hydrofluoric acid. The surface hardness of Examples 1 to 3 as well as the comparative example
Shown in the table.

[Table] From the surface hardness measurement results listed in Table 1, in the case of Example 1, uncoated pure Ti, alloy Ti-
It was confirmed that the surface hardness was higher than that of 6A-4V, and in Examples 2 and 3, the surface hardness was higher than that of ionic Ti nitride, and that it had excellent wear resistance. Next, aluminum coatings of various thicknesses were applied to titanium implant members by ion plating, and alumina layers were formed by anodizing under the same conditions, and their wear resistance was investigated. As a result, when the thickness of the alumina layer was 1 μm or less, no improvement in wear resistance was observed due to the formation of the alumina layer. Also 200μm
Although the wear resistance increases in the above case, it was observed that not only did it take a long time to generate the alumina layer, but it also tended to peel off easily from the surface of the ion plant member. In this example, the surface of the titanium-based implant substrate was coated with aluminum using the ion plating method, but the method is of course not limited to this, and known methods such as molten aluminum plating, aluminum penetration plating, etc. Depending on the application, one or a combination of several methods may be selected, such as a radiation method, a metal cladding method, a vacuum evaporation method, and a sputtering method. In addition, various known methods are available for sealing treatment to further improve the physicochemical properties such as corrosion resistance and abrasion resistance of the anodic oxide coating, including hydration sealing,
Inorganic sealing, organic sealing, etc. can be freely selected using chemical methods and electrochemical methods, and the pores can be sealed with non-biotoxic hardening substances. (Effects of the Invention) As described above, the titanium-alumina composite implant according to the present invention forms an alumina layer with a thickness of 1 to 200 μm on the base of the titanium implant,
A biomedical implant that has excellent not only corrosion resistance but also wear resistance because it is coated with a dense coating layer with good adhesion and filled with a sealing material that is not harmful to the body as necessary. can be provided.

Claims (1)

[Scope of Claims] 1. A titanium-alumina composite implant, characterized in that an alumina layer is adhered to the surface of a metal base made of titanium or a titanium alloy. 2. The titanium-alumina composite implant according to claim 1, wherein the alumina layer has a thickness of 1 to 200 μm. 3. After obtaining a metal base by molding titanium or a titanium alloy into a desired shape, an aluminum coating layer is applied to the surface of the metal base by a known method such as ion plating, thermal spraying, vapor deposition, or plating. 1. A method for producing a titanium-alumina composite implant, which comprises depositing a titanium-alumina composite implant, and then anodizing this coating layer to form an alumina layer.