2005 Fiscal Year Final Research Report Summary
Development of titanium wire ropes for implantable stimulation electrode and their evaluation
| Project/Area Number |
16360342
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Structural/Functional materials
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
IGUCHI Yasutaka Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (90005413)
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| Co-Investigator(Kenkyū-buntansha) |
OUCHI Chiaki Tohoku University, Graduate School of Engineering, Professor, 大学院・工学研究科, 教授 (00312603)
NARUSHIMA Takayuki Tohoku University, Biomedical Engineering Research Organization, Professor, 先進医工学研究機構, 教授 (20198394)
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| Project Period (FY) |
2004 – 2005
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| Keywords | biomaterials / titanium / titanium alloy / rotating-bending fatigue test / wire / biocompatibility / fatigue limit / stimulation electrode |
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| Research Abstract |
1. Development of titanium wore for implantable stimulation electrodes
(1) α+β type Ti-4.5Al-6Nb-2Fe-2M titanium alloy was drawn to the wire with 100 μm in diameter. Anodic oxidation was effective to the oxide formation on the surface for wire drawing. In the atmospheric oxidation for oxide formation process, it was suggested that the low temperature process was preferred.
(2) β type Ti-14Mo-3Nb-1.5Zr titanium alloy was drawn to the wire with 42 μm in diameter. The low temperature atmospheric oxidation was used for oxide formation process on the surface. In addition to that, the β type alloy was drawn to 100 μm in diameter using anodic oxidation, which showed the smooth surface after drawing.
(3) CP titanium (4N) was drawn to the wire with 47 μm in diameter. The surface morphology of this wire was better than that of commercially available CP titanium wire with 46 μm in diameter.
(4) α type Ti-10Zr titanium alloy was drawn to the wire with 51 μm in diameter, which exhibited the excellent surface smoothness and mechanical properties. The wire ropes with 7 and 7x7 strands made of Ti-10Zr titanium alloy were successfully developed.
2. Evaluation
(1) The maximum tensile strength and total elongation of CP titanium wire with 47 μm in diameter were 980 MPa and 3.5 %. The mechanical properties of the β type Ti-14Mo-3Nb-1.5Zr titanium alloy wire and the α type Ti-10Zr titanium alloy wire were measured.
(2) The fatigue limits of the developed CP titanium wire with 47 μm in diameter and commercially available CP titanium wire with 46 μm in diameter were 200 MPa and 300 MPa, respectively. The difference of fatigue limit may be caused by the surface roughness after fatigue testing. The commercially available CP titanium wire exhibited the smoother surface than developed CP titanium wire after 10^7 cycles.
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