The Experts below are selected from a list of 3435 Experts worldwide ranked by ideXlab platform
H.c. Park - One of the best experts on this subject based on the ideXlab platform.
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TBA-based freeze/Gel Casting of porous hydroxyapatite scaffolds
Ceramics International, 2011Co-Authors: June Hong Kim, Jisung Lee, Tae Young Yang, Sang-yong Yoon, Byung Kyu Kim, H.c. ParkAbstract:Abstract Porous ceramic scaffolds with a controlled “designer” pore structure have been prepared by the freeze/Gel Casting route using a TBA-based hydroxyapatite slurry system with 20–40 wt.% solid content. The products were characterized in terms of sintered microstructure, together with physical and mechanical properties. After sintering at 1050–1250 °C, the advantages of freeze Casting and Gel Casting appeared in the pore structure and compressive strength of the ceramics, i.e., unidirectional aligned macro-pore channels developed by controlling the solidification direction of the TBA solvent used in the freeze Casting together with small diameter (micron sized) isolated pores formed in the dense outer walls of the pore channels when processed by Gel Casting. The sintered porosity and pore size generally resulted in a high solid loading giving low porosity and small pore size, this leading to higher compressive strengths. The scaffolds obtained exhibited an average porosity and compressive strength in the range 41.9–79.3% and 35.1–2.7 MPa, respectively, depending on the processing conditions used.
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tba based freeze Gel Casting of porous hydroxyapatite scaffolds
Ceramics International, 2011Co-Authors: June Hong Kim, Jisung Lee, Tae Young Yang, Sang-yong Yoon, Byung Kyu Kim, H.c. ParkAbstract:Abstract Porous ceramic scaffolds with a controlled “designer” pore structure have been prepared by the freeze/Gel Casting route using a TBA-based hydroxyapatite slurry system with 20–40 wt.% solid content. The products were characterized in terms of sintered microstructure, together with physical and mechanical properties. After sintering at 1050–1250 °C, the advantages of freeze Casting and Gel Casting appeared in the pore structure and compressive strength of the ceramics, i.e., unidirectional aligned macro-pore channels developed by controlling the solidification direction of the TBA solvent used in the freeze Casting together with small diameter (micron sized) isolated pores formed in the dense outer walls of the pore channels when processed by Gel Casting. The sintered porosity and pore size generally resulted in a high solid loading giving low porosity and small pore size, this leading to higher compressive strengths. The scaffolds obtained exhibited an average porosity and compressive strength in the range 41.9–79.3% and 35.1–2.7 MPa, respectively, depending on the processing conditions used.
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hydroxyapatite scaffolds processed using a tba based freeze Gel Casting polymer sponge technique
Journal of Materials Science: Materials in Medicine, 2010Co-Authors: Tae Young Yang, Jung Min Lee, Seogyoung Yoon, H.c. ParkAbstract:A novel freeze-Gel Casting/polymer sponge technique has been introduced to fabricate porous hydroxyapatite scaffolds with controlled “designer” pore structures and improved compressive strength for bone tissue engineering applications. Tertiary-butyl alcohol (TBA) was used as a solvent in this work. The merits of each production process, freeze Casting, Gel Casting, and polymer sponge route were characterized by the sintered microstructure and mechanical strength. A reticulated structure with large pore size of 180–360 μm, which formed on burn-out of polyurethane foam, consisted of the strut with highly interconnected, unidirectional, long pore channels (~4.5 μm in dia.) by evaporation of frozen TBA produced in freeze Casting together with the dense inner walls with a few, isolated fine pores (<2 μm) by Gel Casting. The sintered porosity and pore size generally behaved in an opposite manner to the solid loading, i.e., a high solid loading gave low porosity and small pore size, and a thickening of the strut cross section, thus leading to higher compressive strengths.
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Hydroxyapatite scaffolds processed using a TBA-based freeze-Gel Casting/polymer sponge technique.
Journal of Materials Science: Materials in Medicine, 2010Co-Authors: Tae Young Yang, Jung Min Lee, Seogyoung Yoon, H.c. ParkAbstract:A novel freeze-Gel Casting/polymer sponge technique has been introduced to fabricate porous hydroxyapatite scaffolds with controlled “designer” pore structures and improved compressive strength for bone tissue engineering applications. Tertiary-butyl alcohol (TBA) was used as a solvent in this work. The merits of each production process, freeze Casting, Gel Casting, and polymer sponge route were characterized by the sintered microstructure and mechanical strength. A reticulated structure with large pore size of 180–360 μm, which formed on burn-out of polyurethane foam, consisted of the strut with highly interconnected, unidirectional, long pore channels (~4.5 μm in dia.) by evaporation of frozen TBA produced in freeze Casting together with the dense inner walls with a few, isolated fine pores (
Ruiping Liu - One of the best experts on this subject based on the ideXlab platform.
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Fabrication of porous alumina–zirconia ceramics by Gel-Casting and infiltration methods
Materials & Design, 2014Co-Authors: Ruiping Liu, Chang-an Wang, Shengnian TieAbstract:Abstract Porous alumina–zirconia ceramics were obtained by infiltrating porous alumina ceramics, which were prepared by tert-butyl alcohol (TBA)-based Gel-Casting method. Back scattering images of the fracture surface and energy dispersive spectroscopy were performed to obtain composition profiles on the fracture surface and across sections of the sintered composites. The porosity, pore size distribution and compressive strength were also investigated. The results show that the content of zirconia can be adjusted effectively by infiltration times and it decreases with increasing distance from the surface of the samples. The porosity and compressive strength can also be controlled by the infiltration times. With increases of the infiltration times from 1 to 3 cycles, the open porosity decreases slightly from 62.43% to 56.62%, while the compressive strength of the porous alumina–zirconia ceramics increases from 13.57 ± 1.21 to 26.87 ± 2.01 MPa, indicating that the porous ceramics with high porosity and high strength can be prepared by TBA-based Gel-Casting method combined with the infiltration process.
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fabrication of porous alumina zirconia ceramics by Gel Casting and infiltration methods
Materials & Design, 2014Co-Authors: Ruiping Liu, Chang-an Wang, Shengnian TieAbstract:Abstract Porous alumina–zirconia ceramics were obtained by infiltrating porous alumina ceramics, which were prepared by tert-butyl alcohol (TBA)-based Gel-Casting method. Back scattering images of the fracture surface and energy dispersive spectroscopy were performed to obtain composition profiles on the fracture surface and across sections of the sintered composites. The porosity, pore size distribution and compressive strength were also investigated. The results show that the content of zirconia can be adjusted effectively by infiltration times and it decreases with increasing distance from the surface of the samples. The porosity and compressive strength can also be controlled by the infiltration times. With increases of the infiltration times from 1 to 3 cycles, the open porosity decreases slightly from 62.43% to 56.62%, while the compressive strength of the porous alumina–zirconia ceramics increases from 13.57 ± 1.21 to 26.87 ± 2.01 MPa, indicating that the porous ceramics with high porosity and high strength can be prepared by TBA-based Gel-Casting method combined with the infiltration process.
Claudia Ossa Orozco - One of the best experts on this subject based on the ideXlab platform.
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Suspension Rheology, Porosity and Mechanical Strength of Porous Hydroxyapatite Obtained by Gel-Casting and Infiltration
Journal of Materials Engineering and Performance, 2016Co-Authors: Jazmín González Ocampo, Mateo Escobar Jaramillo, Diana Escobar Sierra, Claudia Ossa OrozcoAbstract:The Gel-Casting technique (GC) and infiltration of polymer foam combined with Gel-Casting (IG) were used to produce hydroxyapatite porous bodies. Due to the fact that the process begins with the preparation of the suspensions, it is necessary to know the rheological properties of the ceramic slurry. This is a critical factor needed to optimize the mechanical strength of the porous body obtained. Therefore, the rheological behavior of various HA slurries was assessed. 40 and 50% solids and three different monomers were evaluated. Subsequently, the compressive strength and porosity of the porous bodies obtained were evaluated. The results revealed that the chemical composition of each monomer can affect the dispersion and rheological properties of the suspension, which directly affects the mechanical properties of the porous bodies. The porous bodies obtained by the GC technique showed strengths higher than those obtained by IG compression. The control executed over the rheology of the suspension was more effective in bodies produced by GC, because IG pyrolysis of polyurethane foam also influenced the mechanical properties of the final product.
Guangyao Meng - One of the best experts on this subject based on the ideXlab platform.
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BaZr0.1Ce0.7Y0.2O3−δ proton-conducting electrolyte prepared by Gel-Casting for low-temperature solid oxide fuel cells
Journal of Alloys and Compounds, 2009Co-Authors: Hanping Ding, Bin Lin, Daru Fang, Yingchao Dong, Songlin Wang, Xingqin Liu, Guangyao MengAbstract:Abstract BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (BZCY7) perovskite oxide was prepared by Gel-Casting and solid-state reaction techniques as proton-conducting electrolyte for low-temperature solid oxide fuel cells (LT-SOFCs). X-ray diffraction analysis indicated that the phase formation temperature of BZCY7 powder synthesized by Gel-Casting was 100–150 °C lower than that by solid-state reaction method. The BZCY7 electrolytes prepared by Gel-Casting exhibited better sintering activity and higher electrical conductivity. After sintering at 1550 °C for 5 h, the relative density and electrical conductivity of the Gel-Casting derived BZCY7 reached 95% and 5 × 10 −3 S/cm in H 2 (∼3% H 2 O) at 500 °C. However, for the solid-state reaction method, the sample had a relative density of 86% and electrical conductivity of 2 × 10 −3 S/cm under the same condition.
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BaZr0.1Ce0.7Y0.2O3−δ proton-conducting electrolyte prepared by Gel-Casting for low-temperature solid oxide fuel cells
Journal of Alloys and Compounds, 2009Co-Authors: Hanping Ding, Bin Lin, Daru Fang, Yingchao Dong, Songlin Wang, Xingqin Liu, Guangyao MengAbstract:BaZr0.1Ce0.7Y0.2O3-δ (BZCY7) perovskite oxide was prepared by Gel-Casting and solid-state reaction techniques as proton-conducting electrolyte for low-temperature solid oxide fuel cells (LT-SOFCs). X-ray diffraction analysis indicated that the phase formation temperature of BZCY7 powder synthesized by Gel-Casting was 100-150 °C lower than that by solid-state reaction method. The BZCY7 electrolytes prepared by Gel-Casting exhibited better sintering activity and higher electrical conductivity. After sintering at 1550 °C for 5 h, the relative density and electrical conductivity of the Gel-Casting derived BZCY7 reached 95% and 5 × 10-3 S/cm in H2 (∼3% H2O) at 500 °C. However, for the solid-state reaction method, the sample had a relative density of 86% and electrical conductivity of 2 × 10-3 S/cm under the same condition. © 2008 Elsevier B.V. All rights reserved.link_to_subscribed_fulltex
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prontonic ceramic membrane fuel cells with layered gdbaco2o5 x cathode prepared by Gel Casting and suspension spray
Journal of Power Sources, 2008Co-Authors: Shangquan Zhang, Hanping Ding, Linchao Zhang, Lei Bi, Guangyao MengAbstract:Abstract In order to develop a simple and cost-effective route to fabricate protonic ceramic membrane fuel cells (PCMFCs) with layered GdBaCo 2 O 5+ x (GBCO) cathode, a dense BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (BZCY7) electrolyte was fabricated on a porous anode by Gel-Casting and suspension spray. The porous NiO–BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (NiO–BZCY7) anode was directly prepared from metal oxide (NiO, BaCO 3 , ZrO 2 , CeO 2 and Y 2 O 3 ) by a simple Gel-Casting process. A suspension of BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ powders synthesized by Gel-Casting was then employed to deposit BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (BZCY7) thin layer by pressurized spray process on NiO–BZCY7 anode. The bi-layer with 10 μm dense BZCY7 electrolyte was obtained by co-sintering at 1400 °C for 5 h. With layered GBCO cathode synthesized by Gel-Casting on the bi-layer, single cells were assembled and tested with H 2 as fuel and the static air as oxidant. An open-circuit potential of 0.98 V, a maximum power density of 266 mW cm −2 , and a low polarization resistance of the electrodes of 0.16 Ω cm 2 was achieved at 700 °C.
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Prontonic ceramic membrane fuel cells with layered GdBaCo2O5+x cathode prepared by Gel-Casting and suspension spray
Journal of Power Sources, 2008Co-Authors: Bin Lin, Hanping Ding, Xingqin Liu, Shangquan Zhang, Linchao Zhang, Jianfeng Gao, Guangyao MengAbstract:Abstract In order to develop a simple and cost-effective route to fabricate protonic ceramic membrane fuel cells (PCMFCs) with layered GdBaCo 2 O 5+ x (GBCO) cathode, a dense BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (BZCY7) electrolyte was fabricated on a porous anode by Gel-Casting and suspension spray. The porous NiO–BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (NiO–BZCY7) anode was directly prepared from metal oxide (NiO, BaCO 3 , ZrO 2 , CeO 2 and Y 2 O 3 ) by a simple Gel-Casting process. A suspension of BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ powders synthesized by Gel-Casting was then employed to deposit BaZr 0.1 Ce 0.7 Y 0.2 O 3− δ (BZCY7) thin layer by pressurized spray process on NiO–BZCY7 anode. The bi-layer with 10 μm dense BZCY7 electrolyte was obtained by co-sintering at 1400 °C for 5 h. With layered GBCO cathode synthesized by Gel-Casting on the bi-layer, single cells were assembled and tested with H 2 as fuel and the static air as oxidant. An open-circuit potential of 0.98 V, a maximum power density of 266 mW cm −2 , and a low polarization resistance of the electrodes of 0.16 Ω cm 2 was achieved at 700 °C.
Shengnian Tie - One of the best experts on this subject based on the ideXlab platform.
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Fabrication of porous alumina–zirconia ceramics by Gel-Casting and infiltration methods
Materials & Design, 2014Co-Authors: Ruiping Liu, Chang-an Wang, Shengnian TieAbstract:Abstract Porous alumina–zirconia ceramics were obtained by infiltrating porous alumina ceramics, which were prepared by tert-butyl alcohol (TBA)-based Gel-Casting method. Back scattering images of the fracture surface and energy dispersive spectroscopy were performed to obtain composition profiles on the fracture surface and across sections of the sintered composites. The porosity, pore size distribution and compressive strength were also investigated. The results show that the content of zirconia can be adjusted effectively by infiltration times and it decreases with increasing distance from the surface of the samples. The porosity and compressive strength can also be controlled by the infiltration times. With increases of the infiltration times from 1 to 3 cycles, the open porosity decreases slightly from 62.43% to 56.62%, while the compressive strength of the porous alumina–zirconia ceramics increases from 13.57 ± 1.21 to 26.87 ± 2.01 MPa, indicating that the porous ceramics with high porosity and high strength can be prepared by TBA-based Gel-Casting method combined with the infiltration process.
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fabrication of porous alumina zirconia ceramics by Gel Casting and infiltration methods
Materials & Design, 2014Co-Authors: Ruiping Liu, Chang-an Wang, Shengnian TieAbstract:Abstract Porous alumina–zirconia ceramics were obtained by infiltrating porous alumina ceramics, which were prepared by tert-butyl alcohol (TBA)-based Gel-Casting method. Back scattering images of the fracture surface and energy dispersive spectroscopy were performed to obtain composition profiles on the fracture surface and across sections of the sintered composites. The porosity, pore size distribution and compressive strength were also investigated. The results show that the content of zirconia can be adjusted effectively by infiltration times and it decreases with increasing distance from the surface of the samples. The porosity and compressive strength can also be controlled by the infiltration times. With increases of the infiltration times from 1 to 3 cycles, the open porosity decreases slightly from 62.43% to 56.62%, while the compressive strength of the porous alumina–zirconia ceramics increases from 13.57 ± 1.21 to 26.87 ± 2.01 MPa, indicating that the porous ceramics with high porosity and high strength can be prepared by TBA-based Gel-Casting method combined with the infiltration process.
