Abstract: A bone repair material being superior in apatite-forming ability and its stability in a storage and high in scratch resistance is disclosed. The material is produced by a method comprising the steps of: immersing a substrate made of titanium or a titanium alloy in a first aqueous solution that does not contain calcium ions but contains at least one cation selected from the group consisting of sodium ions and potassium ions and is alkaline; immersing the substrate in a second aqueous solution that does not contain phosphate ions but contains calcium ions; heating the substrate in a dry atmosphere; and treating the substrate with hot water of 60° C. or higher or with steam.

Abstract: Bone repair materials are disclosed, from which ions are hardly eluted in living body and which are superior in apatite-forming ability and resistance to apatite peeling and have a scratch resistance high enough for practical use. The material comprises a substrate made of titanium or titanium alloys, and a surface layer, made substantially of titanium oxide, along the surface of the substrate. The substrate has on the surface thereof irregularities of from 1 nm to 10 ?m in average in both width and depth. The layer has a zeta potential of +4.5 mV or more under an aqueous solution environment of pH 6 to 8, and a critical scratch resistance of 35 mN or more when vibration 100 ?m in amplitude is added to a stylus with a spring constant of 200 g/mm on the surface layer and the stylus is moved at a rate of 10 mm/sec under a load increasing at a rate of 100 mN/min.

Abstract: A bone repair material being superior in apatite-forming ability and its stability in a storage and high in scratch resistance is disclosed. The material is produced by a method comprising the steps of: immersing a substrate made of titanium or a titanium alloy in a first aqueous solution that does not contain calcium ions but contains at least one cation selected from the group consisting of sodium ions and potassium ions and is alkaline; immersing the substrate in a second aqueous solution that does not contain phosphate ions but contains calcium ions; heating the substrate in a dry atmosphere; and treating the substrate with hot water of 60° C. or higher or with steam.

Abstract: A bone repair material being superior in apatite-forming ability and its stability in a storage and high in scratch resistance is disclosed. The material is produced by a method comprising the steps of: immersing a substrate made of titanium or a titanium alloy in a first aqueous solution that does not contain calcium ions but contains at least one cation selected from the group consisting of sodium ions and potassium ions and is alkaline; immersing the substrate in a second aqueous solution that does not contain phosphate ions but contains calcium ions; heating the substrate in a dry atmosphere; and treating the substrate with hot water of 60° C. or higher or with steam.

Abstract: Bone repair materials are disclosed, from which ions are hardly eluted in living body and which are superior in apatite-forming ability and resistance to apatite peeling and have a scratch resistance high enough for practical use. The material comprises a substrate made of titanium or titanium alloys, and a surface layer, made substantially of titanium oxide, along the surface of the substrate. The substrate has on the surface thereof irregularities of from 1 nm to 10 ?m in average in both width and depth. The layer has a zeta potential of +4.5 mV or more under an aqueous solution environment of pH 6 to 8, and a critical scratch resistance of 35 mN or more when vibration 100 ?m in amplitude is added to a stylus with a spring constant of 200 g/mm on the surface layer and the stylus is moved at a rate of 10 mm/sec under a load increasing at a rate of 100 mN/min.

Abstract: A bone repair material being superior in apatite-forming ability and its stability in a storage and high in scratch resistance is disclosed. The material is produced by a method comprising the steps of: immersing a substrate made of titanium or a titanium alloy in a first aqueous solution that does not contain calcium ions but contains at least one cation selected from the group consisting of sodium ions and potassium ions and is alkaline; immersing the substrate in a second aqueous solution that does not contain phosphate ions but contains calcium ions; heating the substrate in a dry atmosphere; and treating the substrate with hot water of 60° C. or higher or with steam.

Abstract: An artificial joint member made of a polymeric material including a portion made of a polymeric substance has a sliding surface composed of a polymer having phosphoryl choline groups. With such an arrangement, the artificial joint member is provided with a sliding part capable of keeping a satisfactory lubricating state for a long time.

Abstract: A method for producing an artificial bone precursor is disclosed. The method comprises: extracting a part corresponding to a cancellous bone and/or a cortical bone from digitalized three-dimensional image data of a living bone, followed by setting a center line on the part; drawing a beam or a wall having a uniform diameter or thickness along the center line to form artificial bone image data; and stacking a sintered layer by laser-sintering a powder of titanium and the like based on the artificial bone image data. The precursor is suitable for an artificial bone having excellent osteoconductivity and osteoinductivity.

Abstract: An artificial bone is disclosed. The artificial bone comprises: a porous body comprising a lump of titanium or titanium alloy and having a porosity of 30 to 80%, the body having a interconnected pore (3) with a diameter of 100 to 3000 ?m and a hole (4) with a diameter of 50 ?m or less on an inner surface of the pore; and a film formed on at least a part of a surface of the pore and the hole, the film comprising at least one phase selected from an amorphous titanium oxide phase, an amorphous alkali titanate phase, an anatase phase and a rutile phase aligned with (101) plane. The artificial bone has high strength and osteoinductivity.

Abstract: Disclosed herein is a ceramic member for a medical implant which exhibits improved binding with the bone without detracting from the excellent mechanical properties inherent to the ceramic material. The ceramic member for a medical implant has a surface layer having a roughened surface. When attention is paid to one type of crystal phase of the crystal phases of the ceramics constituting the surface layer, difference between the content in % by mass of this crystal phase of interest in the surface layer and the content in % by mass of this crystal phase of interest deep in the ceramic member is within 10%.

Abstract: An artificial joint member made of a polymeric material including a portion made of a polymeric substance has a sliding surface composed of a polymer having phosphoryl choline groups. With such an arrangement, the artificial joint member is provided with a sliding part capable of keeping a satisfactory lubricating state for a long time.

Abstract: An artificial joint made from a zirconia-alumina composite ceramic and having the capability of providing a good joint motion for a long time period with a high degree of reliability is provided. This artificial joint is composed of a first bone member and a second bone member, which is slidably engaged to a part of the first bone member to form a joint portion. At least one of the first and second bone members is made from the zirconia-alumina composite ceramic comprising a matrix phase of zirconia grains and a second phase of alumina grains dispersed in the matrix phase. The zirconia grains contains ceria as a stabilizer in such an amount that the matrix phase is largely composed of tetragonal zirconia. In addition, this composite ceramic has an average grain size of 0.1 to 1 &mgr;m, preferably 0.1 to 0.8 &mgr;m, and particularly preferably 0.1 to 0.65 &mgr;m.

Abstract: There is disclosed a method for hot lubricated metal extrusion in which a billet is extruded into a solid or tubular form by means of a die and/or a mandrel with an organic lubricant interposed within a container, the method comprising feeding a combustion improver or a mixture of a combustion improver and water into an extruded product thereby burning off the carbide of the lubricant deposited on the surfaces of the extruded product.

Abstract: A method for producing cold rolled titanium strips having good surface quality. The cold rolling of a titanium strip is carried out under the conditions represented by the following formula:X.ltoreq.(48673/Y.sup.1.3283)where X is an average grain size (.mu.m) of the pre-cold rolled titanium strip and Y is a diameter (mm) of the roll for the cold rolling.

Abstract: A die for use in a hot hydrostatic extrusion process, in which a billet comprised of aluminum or an aluminum alloy or a billet having aluminum and an aluminum alloy at its outer periphery is preheated and charged into a container whereupon extrusion is carried out by means of a pressure medium, said die comprising a plurality of stepped conical portions serving as approach portions to the die outlet; said conical portions having conical surfaces whose opening angles increase from the inlet of the die toward the outlet thereof, said conical surface which is closest to said inlet having an opening angle of less than 60 degrees, and the difference between the opening angles between adjacent conical surfaces being less than 90 degrees.

Abstract: A method and machine for use in hydrostatic extrusion wherein a portion of an elastic-plastic viscous pressure medium is introduced into the rear portion of a container, with the rear end thereof being sealed in a fluid tight fashion. The pressure medium being of such a nature that it has a high viscosity and cannot flow by itself. Subsequently, a billet is charged into the container and then a die is mounted in the container at the forward end thereof. The aforesaid pressure medium is caused to fill around the outer circumferential surface of the billet. In this respect, a high pressure seal is provided for the junctions between the die and the forward end of the container and between the die and the forward end of the billet before the pressure medium flows out of the container in a practically negligible small amount, immediately after which a pressure stem is pushed into the container from the rear end thereof, thus proceeding with the hydrostatic extrusion.

Abstract: A hydrostatic extrusion method and apparatus for the extrusion of tubes is disclosed wherein the simplified structure of the nose or tip portion of the billet and the cooperating surfaces of the die defining the die cavity and those of the mandrel facilitate an improved initial sealing among the associated surfaces of the die, billet and mandrel. Such an initial sealing is effected between such interfaces of the members and billet at a point which is located substantially rearwardly from the position at which the actual extrusion to the final tubular configuration occurs between the bearing portion of the die and the cooperating sizing portion of the mandrel. Such structure and method permits the extrusion of tubes having walls of asymmetric or non-circular configurations in cross section, even those of complex configurations.

Abstract: A method and machine for use in hydrostatic extrusion wherein a portion of an elastic-plastic viscous pressure medium is introduced into the rear portion of a container, with the rear end thereof being sealed in a fluid tight fashion. The pressure medium being of such a nature that it has a high viscosity and cannot flow by itself. Subsequently, a billet is charged into the container and then a die is mounted in the container at the forward end thereof. The aforesaid pressure medium is caused to fill around the outer circumferential surface of the billet. In this respect, a high pressure seal is provided for the junctions between the die and the forward end of the container and between the die and the forward end of the billet before the pressure medium flows out of the container in a practically negligible small amount, immediately after which a pressure stem is pushed into the container from the rear end thereof, thus proceeding with the hydrostatic extrusion.

Abstract: In the manufacture of compound billets composed of two or more different metals for use in hydrostatic extrusion, care must be exercised to see whether or not products possessing a predetermined compound status are produced from the compound billets by means of the hydrostatic extrusion process.

Abstract: There are disclosed herein a method and an apparatus for manufacturing tubes or tubular bodies by means of hydrostatic extrusion, which tubes or tubular bodies have axially running holes therethrough having cross-sections of irregular shapes. The method and apparatus utilize a mandrel of novel construction which comprises a conical tip portion having a smooth peripheral surface, a cut or grooved intermediate portion with a sloped groove starting at a peripheral edge and a body portion formed with a flange and adapted to move longitudinally of a pressure chamber, as necessary. The conical tip portion is specifically intended to seal against the conical end of a metallic billet. Unless there is such a provision, there would be leakage of a fluid through the grooved portion because of direct contact of the grooved edge with the inner end surface of the billet.