To improve the adhesiveness to a base material, and prevent breakage, separation and elution to a body fluid by forming an amorphous apatite film directly or indirectly on the surface of a base material for a biological material, and forming a c-axis oriented crystal apatite film on the outermost layer.
An amorphous apatite film 2 about 0.1-5 μm thick and a c-axis oriented crystal apatite film 3 are stacked in order on a base material 1 formed of suitable material by sputtering. At the time of sputtering, the temperature of the base material 1 is 50°C or less in forming the amorphous apatite film 2, and 250-500°C in forming the c-axis oriented crystal apatite film 3. Thus, an amorphous apatite film 2 having great joint strength can be formed so as to improve the joining performance. Further, the c-axis oriented crystal apatite film 3 which has good affinity to a living body and has little elution to a body fluid can be formed on the outermost layer so as to improve durability.
ARAKI KATSUYUKI
ITO HIDEAKI
SAKAKAWA TATSUAKI
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