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Shiro Miyaji - One of the best experts on this subject based on the ideXlab platform.
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bone bonding behavior of Titanium and its alloys when coated with Titanium oxide Tio2 and Titanium silicate Ti5si3
Journal of Biomedical Materials Research, 1996Co-Authors: Toshiaki Kitsugi, Takashi Nakamura, Masanori Oka, Weiqi Yan, Tatsuya Goto, Takehiro Shibuya, Tadashi Kokubo, Shiro MiyajiAbstract:It has been proposed that the essenTial requirement for arTificial materials to bond to living bone is the formaTion of bone-like apaTite on their surfaces in the body. Recent studies have shown that Titanium hydrogel and silica gel induce apaTite formaTion on their surface in a simulated body fluid. In this study, the influence of Titanium oxide and Titanium silicate on the bonding of Titanium alloys to bone was studied. Rectangular implants (15 × 10 × 2.2 mm) of Titanium, Ti-6Al-4V, Ti-6Al-2Nb-Ta, Ti-6Al-4V coated with TiO2, and Ti-6Al-4V coated with Ti5Si3 were implanted into the Tibial metaphyses of mature rabbits. At 8 and 24 weeks after implantaTion, the Tibiae containing the implants were dissected out and subjected to a detaching tesTing. The failure load for Titanium, Ti-6Al-4V, Ti-6Al-2Nb-Ta, Ti-6Al-4V coated with TiO2, and Ti-6Al-4V coated with Ti5Si3 were, respecTively, 0.68 ± 0.48, 0.22 ± 0.46, 0.67 ± 0.59, 2.18 ± 0.71 and 2.03 ± 0.41 kgf at 8 weeks, and 2.7 ± 0.91, 2.58 ± 1.29, 2.38 ± 0.41, 3.79 ± 1.7, and 2.79 ± 0.87 kgf at 24 weeks after implantaTion. Histological examinaTion by Giemsa surface staining, CMR, and SEM-EPMA revealed the coated Titanium alloy implants directly bonded to bone Tissue during early implantaTion. A Ca-P layer was observed at the interface of the coated implants and the bone. The results of this study indicated that TiO2 and Ti5Si3 can enhance the early bonding of Titanium alloys to bone by inducing a Ca-P layer (chemical apaTite) on the surface of Titanium alloys. It also is suggested that the direct bone contact occurs in relaTion to the calcium and phosphorus adsorpTion onto the surface of the Titanium passive layer formed during long-term implantaTion. © 1996 John Wiley & Sons, Inc.
Younghag Koh - One of the best experts on this subject based on the ideXlab platform.
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dynamic freeze casTing for the producTion of porous Titanium Ti scaffolds
Materials Science and Engineering: C, 2013Co-Authors: Hyundo Jung, Se Won Yook, Hyounee Kim, Taesik Jang, Yuanlong Li, Younghag KohAbstract:Abstract This paper proposes dynamic freeze casTing as a new manufacturing technique for producing porous Ti scaffolds with a uniform porous structure and good ducTility. In this method, Ti/camphene slurries with various iniTial Ti contents (15, 20, and 25 vol.%) were frozen at 44 °C for 12 h in rotaTion, which allowed for the extensive growth of camphene crystals and the uniform construcTion of walls made of Ti parTicles. All the fabricated samples showed spherical-like pores surrounded by dense Ti walls that were uniformly formed after sintering at 1300 °C for 2 h in a vacuum. The porosity decreased from 71 to 52 vol.% with an increase in Ti content from 15 to 25 vol.%, whereas the pore size decreased from 362 to 95 μm. On the other hand, the compressive strength and sTiffness increased considerably from 57 ± 4 to 183 ± 6 MPa and from 1.3 ± 0.5 to 5.0 ± 0.8 GPa, respecTively, due to the decrease in the porosity of the samples.
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fabricaTion of porous Titanium scaffolds with high compressive strength using camphene based freeze casTing
Materials Letters, 2009Co-Authors: Se Won Yook, Hyounee Kim, Younghag KohAbstract:Abstract We herein report the fabricaTion of highly porous Titanium (Ti) scaffolds with unusually high compressive strength by freezing a Titanium hydride (TiH 2 )/camphene slurries at 42 °C. As the freezing Time was increased from 1 to 7 days, the pore size obtained was increased significantly from 143 to 271 μm due to the conTinual overgrowth of camphene dendrites. However, interesTingly, the formaTion of the micro-pores inside the Ti walls was suppressed at longer freezing Time. This resulted in a significant increase in compressive strength up to 110 ± 17 MPa with a porosity of 64%. It is believed that this unusually high compressive strength with large interconnected pores makes this material suitable for applicaTions as load-bearing parts.
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porous Titanium Ti scaffolds by freezing Tih2 camphene slurries
Materials Letters, 2008Co-Authors: Se Won Yook, Byungho Yoon, Hyounee Kim, Younghag Koh, Yong Sik KimAbstract:Abstract Porous Titanium (Ti) scaffolds with interconnected pores were fabricated by freezing Titanium hydride (TiH 2 )/camphene slurries at 33 °C for 24 h, followed by freeze-drying and subsequent heat-treatment at 1300 °C for 2 h in vacuum. All of the fabricated samples revealed highly porous structures having large pores up to 100 μm in size surrounded by Ti metal walls without any secondary phases. When the iniTial TiH 2 content was increased from 15 to 25 vol.%, the porosity was decreased from 63 to 49%, while the compressive strength was significantly improved from 81 to 253 MPa.
Hyounee Kim - One of the best experts on this subject based on the ideXlab platform.
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effect of hf hno3 treatment on the porous structure and cell penetrability of Titanium Ti scaffold
Materials & Design, 2018Co-Authors: Hyun Soon Lee, Hyounee Kim, Hyundo Jung, Minho Kang, Juha Song, Taesik JangAbstract:Abstract Porous Titanium (Ti) implants have been used in orthopedic and dental applicaTions because of their superior mechanical properTies. Sufficient pore interconnecTivity is required for effecTive bone regeneraTion and growth inside the Ti scaffold pore structure. We proposed post-treatment with HF/HNO3 to efficiently modify the internal pore structure of a Ti scaffold and achieve controllable mechanical properTies with a pore neck structure. The porosity, pore size, wall thickness, and pore neck size were easily controlled by varying the acid treatment Time, which produced a Ti scaffold with mechanical properTies that were suitable for bone Tissue engineering. As the mixed acid treatment Time increased, internal isolated pores were gradually interconnected with adjacent pores. After 10 min of treatment, nearly all the pores were interconnected. The post-treatment with HF/HNO3 also affected the surface properTies. Surface carbon contaminants were significantly reduced after treatment with no hydride formaTion. Micron-scale surface roughness was uniformly generated across the whole surface. The actual cell penetrability of the Ti scaffold was evaluated using a perfusion-based in vitro cell test. Over 90% of the surface pores depict cell penetrability with a sufficient number of cells attached to the wall surface of the pore after performing acid treatment for 12 min.
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dynamic freeze casTing for the producTion of porous Titanium Ti scaffolds
Materials Science and Engineering: C, 2013Co-Authors: Hyundo Jung, Se Won Yook, Hyounee Kim, Taesik Jang, Yuanlong Li, Younghag KohAbstract:Abstract This paper proposes dynamic freeze casTing as a new manufacturing technique for producing porous Ti scaffolds with a uniform porous structure and good ducTility. In this method, Ti/camphene slurries with various iniTial Ti contents (15, 20, and 25 vol.%) were frozen at 44 °C for 12 h in rotaTion, which allowed for the extensive growth of camphene crystals and the uniform construcTion of walls made of Ti parTicles. All the fabricated samples showed spherical-like pores surrounded by dense Ti walls that were uniformly formed after sintering at 1300 °C for 2 h in a vacuum. The porosity decreased from 71 to 52 vol.% with an increase in Ti content from 15 to 25 vol.%, whereas the pore size decreased from 362 to 95 μm. On the other hand, the compressive strength and sTiffness increased considerably from 57 ± 4 to 183 ± 6 MPa and from 1.3 ± 0.5 to 5.0 ± 0.8 GPa, respecTively, due to the decrease in the porosity of the samples.
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fabricaTion of porous Titanium scaffolds with high compressive strength using camphene based freeze casTing
Materials Letters, 2009Co-Authors: Se Won Yook, Hyounee Kim, Younghag KohAbstract:Abstract We herein report the fabricaTion of highly porous Titanium (Ti) scaffolds with unusually high compressive strength by freezing a Titanium hydride (TiH 2 )/camphene slurries at 42 °C. As the freezing Time was increased from 1 to 7 days, the pore size obtained was increased significantly from 143 to 271 μm due to the conTinual overgrowth of camphene dendrites. However, interesTingly, the formaTion of the micro-pores inside the Ti walls was suppressed at longer freezing Time. This resulted in a significant increase in compressive strength up to 110 ± 17 MPa with a porosity of 64%. It is believed that this unusually high compressive strength with large interconnected pores makes this material suitable for applicaTions as load-bearing parts.
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porous Titanium Ti scaffolds by freezing Tih2 camphene slurries
Materials Letters, 2008Co-Authors: Se Won Yook, Byungho Yoon, Hyounee Kim, Younghag Koh, Yong Sik KimAbstract:Abstract Porous Titanium (Ti) scaffolds with interconnected pores were fabricated by freezing Titanium hydride (TiH 2 )/camphene slurries at 33 °C for 24 h, followed by freeze-drying and subsequent heat-treatment at 1300 °C for 2 h in vacuum. All of the fabricated samples revealed highly porous structures having large pores up to 100 μm in size surrounded by Ti metal walls without any secondary phases. When the iniTial TiH 2 content was increased from 15 to 25 vol.%, the porosity was decreased from 63 to 49%, while the compressive strength was significantly improved from 81 to 253 MPa.
Yanxin Qiao - One of the best experts on this subject based on the ideXlab platform.
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comparison of the corrosion behavior of pure Titanium and its alloys in fluoride containing sulfuric acid
Corrosion Science, 2016Co-Authors: Zhen Wang, H X Hu, Yong Zheng, Wei Ke, Yanxin QiaoAbstract:Abstract The corrosion behavior of pure Titanium, Ti-0.2Pd and Ti-0.3Mo-0.8Ni alloy in fluoride-containing sulfuric acid were invesTigated using electrochemical methods combined with surface characterizaTion. The results showed that Titanium alloys exhibited higher corrosion resistance than pure Titanium at fluoride concentraTions lower than 0.002 M due to the acceleraTion effects of Pd and Ni on cathodic process and the inhibiTion effect of Mo on anodic process. But Titanium alloys are sTill corroded as severely as pure Titanium at higher fluoride concentraTions. The influences of alloying elements on the corrosion behavior at different fluoride concentraTions were well explained using the mixed potenTial theory.
Se Won Yook - One of the best experts on this subject based on the ideXlab platform.
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dynamic freeze casTing for the producTion of porous Titanium Ti scaffolds
Materials Science and Engineering: C, 2013Co-Authors: Hyundo Jung, Se Won Yook, Hyounee Kim, Taesik Jang, Yuanlong Li, Younghag KohAbstract:Abstract This paper proposes dynamic freeze casTing as a new manufacturing technique for producing porous Ti scaffolds with a uniform porous structure and good ducTility. In this method, Ti/camphene slurries with various iniTial Ti contents (15, 20, and 25 vol.%) were frozen at 44 °C for 12 h in rotaTion, which allowed for the extensive growth of camphene crystals and the uniform construcTion of walls made of Ti parTicles. All the fabricated samples showed spherical-like pores surrounded by dense Ti walls that were uniformly formed after sintering at 1300 °C for 2 h in a vacuum. The porosity decreased from 71 to 52 vol.% with an increase in Ti content from 15 to 25 vol.%, whereas the pore size decreased from 362 to 95 μm. On the other hand, the compressive strength and sTiffness increased considerably from 57 ± 4 to 183 ± 6 MPa and from 1.3 ± 0.5 to 5.0 ± 0.8 GPa, respecTively, due to the decrease in the porosity of the samples.
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fabricaTion of porous Titanium scaffolds with high compressive strength using camphene based freeze casTing
Materials Letters, 2009Co-Authors: Se Won Yook, Hyounee Kim, Younghag KohAbstract:Abstract We herein report the fabricaTion of highly porous Titanium (Ti) scaffolds with unusually high compressive strength by freezing a Titanium hydride (TiH 2 )/camphene slurries at 42 °C. As the freezing Time was increased from 1 to 7 days, the pore size obtained was increased significantly from 143 to 271 μm due to the conTinual overgrowth of camphene dendrites. However, interesTingly, the formaTion of the micro-pores inside the Ti walls was suppressed at longer freezing Time. This resulted in a significant increase in compressive strength up to 110 ± 17 MPa with a porosity of 64%. It is believed that this unusually high compressive strength with large interconnected pores makes this material suitable for applicaTions as load-bearing parts.
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porous Titanium Ti scaffolds by freezing Tih2 camphene slurries
Materials Letters, 2008Co-Authors: Se Won Yook, Byungho Yoon, Hyounee Kim, Younghag Koh, Yong Sik KimAbstract:Abstract Porous Titanium (Ti) scaffolds with interconnected pores were fabricated by freezing Titanium hydride (TiH 2 )/camphene slurries at 33 °C for 24 h, followed by freeze-drying and subsequent heat-treatment at 1300 °C for 2 h in vacuum. All of the fabricated samples revealed highly porous structures having large pores up to 100 μm in size surrounded by Ti metal walls without any secondary phases. When the iniTial TiH 2 content was increased from 15 to 25 vol.%, the porosity was decreased from 63 to 49%, while the compressive strength was significantly improved from 81 to 253 MPa.