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Ti-49.5Ni (at%)합금의 다공성 구조가 뼈 세포 흡착에 미치는 영향
임연민,최정일,강동우,남태현,Im, Yeon-Min,Choi, Jung-Il,Khang, Dong-Woo,Nam, Tae-Hyun 한국재료학회 2012 한국재료학회지 Vol.22 No.2
Ti-Ni alloys are widely used in numerous biomedical applications (e.g., orthodontics, cardiovascular science, orthopaedics) due to their distinctive thermomechanical and mechanical properties, such as the shape memory effect, superelasticity and low elastic modulus. In order to increase the biocompatibility of Ti-Ni alloys, many surface modification techniques, such as the sol-gel technique, plasma immersion ion implantation (PIII), laser surface melting, plasma spraying, and chemical vapor deposition, have been employed. In this study, a Ti-49.5Ni (at%) alloy was electrochemically etched in 1M $H_2SO_4$+ X (1.5, 2.0, 2.5) wt% HF electrolytes to modify the surface morphology. The morphology, element distribution, crystal structure, roughness and energy of the surface were investigated by scanning electron microscopy (SEM), energy-dispersive Xray spectrometry (EDS), X-ray diffractometry (XRD), atomic force microscopy (AFM) and contact angle analysis. Micro-sized pores were formed on the Ti-49.5Ni (at%) alloy surface by electrochemical etching with 1M $H_2SO_4$+ X (1.5, 2.0, 2.5) wt% HF. The volume fractions of the pores were increased by increasing the concentration of the HF electrolytes. Depending on the HF concentration, different pore sizes, heights, surface roughness levels, and surface energy levels were obtained. To investigate the osteoblast adhesion of the electrochemically etched Ti-49.5Ni (at%) alloy, a MTT test was performed. The degree of osteoblast adhesion was increased at a high concentration of HF-treated surface structures.
Gas atomization으로 제조된 Ti50Ni30Cu20 합금 분말의 상변태 거동
최은수 ( Eun Soo Choi ),남태현 ( Tae Hyun Nam ),정영수 ( Young Soo Chung ),김연욱 ( Yoen Wook Kim ),임연민 ( Yeon Min Im ) 한국주조공학회 2011 한국주조공학회지 Vol.31 No.1
For the fabrication of bulk near-net-shape Ti-Ni-Cu shape memory alloys, consolidation of Ti-Ni-Cu alloy powders are useful because of their brittle property. In the present study, Ti50Ni30Cu20 shape memory alloy powders were prepared by gas atomization and martensitic transformation temperatures and microstructures of those powders were investigated as a function of powder size. The size distribution of the powders was measured by conventional sieving, and sieved powders with the specific size range of 25 to 150 μm were chosen for this examination. XRD analysis showed that the B2-B19 martensitic transformation occurred in the powders. In DSC curves of the as-atomized Ti50Ni30Cu20 powders as a function of powder size, only one clear peak was found on each cooling and heating curve. The martensitic transformation start temperature(Ms) of the 25-50 μm powders was 31.5oC. The Ms increased with increasing powder size and the difference of Ms between 25-50 μm powders and 100-150 μm powders is only 1oC. The typical microstructure of the rapidly solidified powders showed cellular morphology and very small pores were observed in intercellular regions.