TY - GEN
T1 - Carbon-based nanostructured coatings on NiTi shape memory alloy for biomedical applications
AU - Takeno, Takanori
AU - Shiota, Hiroyuki
AU - Miki, Hiroyuki
AU - Takagi, Toshiyuki
AU - Luo, Yun
N1 - Funding Information:
This work was partially supported by a Graint-in-Aid for Scientific Research (B) (20360380) from the Japan Society for the Promotion of Science (JSPS), the Global COE program, ”World Center of Education and Research for Transdisciplinary Flow Dynamics” by the Ministry of Education, Culture, Sports, Science and Technology, Japan, and by the State Key Laboratory of Mechanical System and Vibration, Shanghai Jiao Tong University, China. We are thankful to Mr. Takeshi Sato in the Institute of Fluid Science, Tohoku University, Japan, for his technical assistance.
PY - 2010
Y1 - 2010
N2 - Here, we propose carbon-based nanostructured coatings for nickel-titanium (NiTi) shape memory alloys (SMAs) for biomedical applications. NiTi SMAs are well-known biomedical materials; however, the elution of toxic Ni ions into the body has prevented SMAs from expanding their applications, particularly in the complete implantation of SMAs for human artificial muscles. One possibility for the suppression of leaching ions is to create a barrier coating, for which diamond-like carbon (DLC) may be a candidate. Due to the strong internal stress derived from the mismatch of the thermal expansion coefficient, however, the adhesive strength of DLCs is very low. In this study, we focused on the incorporation of tungsten into a DLC in order to reduce the internal stress of the coating. First, we present the definition of appropriate fabrication conditions. Uniaxial tensile tests were then performed, and we evaluated the adhesive strength of the coatings. We then determined the conditions that support the fabrication of a coating with the strongest adhesive strength. Thereafter, we deposited the coating onto the SMA with shape memory effects and conducted self-bending tests. We observed that the cracks initiated parallel to the longer direction of the specimens, most likely a result of a boundary slip between the parent phases of the SMA. The removed fraction area of the coating was estimated at less than 1 % after 105 cycles, indicating the potential usage of tungsten-containing DLC coatings for biomedical applications.
AB - Here, we propose carbon-based nanostructured coatings for nickel-titanium (NiTi) shape memory alloys (SMAs) for biomedical applications. NiTi SMAs are well-known biomedical materials; however, the elution of toxic Ni ions into the body has prevented SMAs from expanding their applications, particularly in the complete implantation of SMAs for human artificial muscles. One possibility for the suppression of leaching ions is to create a barrier coating, for which diamond-like carbon (DLC) may be a candidate. Due to the strong internal stress derived from the mismatch of the thermal expansion coefficient, however, the adhesive strength of DLCs is very low. In this study, we focused on the incorporation of tungsten into a DLC in order to reduce the internal stress of the coating. First, we present the definition of appropriate fabrication conditions. Uniaxial tensile tests were then performed, and we evaluated the adhesive strength of the coatings. We then determined the conditions that support the fabrication of a coating with the strongest adhesive strength. Thereafter, we deposited the coating onto the SMA with shape memory effects and conducted self-bending tests. We observed that the cracks initiated parallel to the longer direction of the specimens, most likely a result of a boundary slip between the parent phases of the SMA. The removed fraction area of the coating was estimated at less than 1 % after 105 cycles, indicating the potential usage of tungsten-containing DLC coatings for biomedical applications.
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U2 - 10.1007/978-3-642-16587-0_67
DO - 10.1007/978-3-642-16587-0_67
M3 - Conference contribution
AN - SCOPUS:78650466668
SN - 3642165869
SN - 9783642165863
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 742
EP - 753
BT - Intelligent Robotics and Applications - Third International Conference, ICIRA 2010, Proceedings
T2 - 3rd International Conference on Intelligent Robotics and Applications, ICIRA 2010
Y2 - 10 November 2010 through 12 November 2010
ER -