The Experts below are selected from a list of 84 Experts worldwide ranked by ideXlab platform
S. Ebisu - One of the best experts on this subject based on the ideXlab platform.
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microstructure and mechanical property of synthesized hydroxyapatite prepared by colloidal process
Biomaterials, 2000Co-Authors: Hideyuki Yasuda, S. Mahara, Yukichi Umakoshi, Satoshi Imazato, S. EbisuAbstract:Synthesized hydroxyapatite (HAp) was prepared by the colloidal process. Mixed slurry composed of 25 vol% HAp Powder and 75 vol% aqueous solution containing a small amount of polycarboxylic acid ammonium as dispersant was produced. Viscosity of the HAp slurry, microstructure and mechanical property of the synthesized HAp prepared by this process depends on the quantity of dispersant. A mainly uniform microstructure was obtained in both green and sintered HAp with 2 wt% dispersant by preventing the Agglomeration of Powder in the slurry. A homogeneous microstructure was maintained even after annealing at temperatures between 1200 and 1400 degrees C. Maximum bending strength of 88.5 MPa was also obtained at an optimum dispersant concentration.
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Microstructure and mechanical property of synthesized hydroxyapatite prepared by colloidal process.
Biomaterials, 2000Co-Authors: Hideyuki Yasuda, S. Mahara, Yukichi Umakoshi, Satoshi Imazato, S. EbisuAbstract:Abstract Synthesized hydroxyapatite (HAp) was prepared by the colloidal process. Mixed slurry composed of 25 vol% HAp Powder and 75 vol% aqueous solution containing a small amount of polycarboxylic acid ammonium as dispersant was produced. Viscosity of the HAp slurry, microstructure and mechanical property of the synthesized HAp prepared by this process depends on the quantity of dispersant. A mainly uniform microstructure was obtained in both green and sintered HAp with 2 wt% dispersant by preventing the Agglomeration of Powder in the slurry. A homogeneous microstructure was maintained even after annealing at temperatures between 1200 and 1400°C. Maximum bending strength of 88.5 MPa was also obtained at an optimum dispersant concentration.
Thomas A. Wolfe - One of the best experts on this subject based on the ideXlab platform.
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Effect of ammonium dimolybdate (ADM) on the reduction of molybdenum trioxide
International Journal of Refractory Metals and Hard Materials, 2012Co-Authors: Ravi K. Enneti, Thomas A. WolfeAbstract:Abstract Ammonium dimolybdate ((NH 4 ) 2 Mo 2 O 7 ) or molybdenum trioxide (MoO 3 ) is used as starting raw materials for manufacturing Mo Powders. In the initial step, usually carried out in rotary calciners, (NH 4 ) 2 Mo 2 O 7 or MoO 3 is reduced to MoO 2 . Agglomeration of Powder due to melting of eutectic formed between MoO 3 and Mo 4 O 11 and due to melting of MoO 3 occurs during this reduction step resulting in several manufacturing issues. The reduction from (NH 4 ) 2 Mo 2 O 7 involves an endothermic reaction however, reduction of MoO 3 occurs only by exothermic reaction. It is hypothesized that addition of (NH 4 ) 2 Mo 2 O 7 to MoO 3 will decrease Agglomeration of Powders due to the endothermic reaction involved in the reduction process. The current paper details experiments carried out to verify the hypothesis. MoO 3 containing varying amounts (NH 4 ) 2 Mo 2 O 7 were reduced at 550 °C, 650 °C and 750 °C in hydrogen atmosphere. The results show lower Agglomeration of Powder with addition of (NH 4 ) 2 Mo 2 O 7 . The thermal analysis results confirm reduction of MoO 3 at lower temperatures with the addition of (NH 4 ) 2 Mo 2 O 7 .
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Agglomeration during reduction of MoO3
International Journal of Refractory Metals and Hard Materials, 2012Co-Authors: Ravi K. Enneti, Thomas A. WolfeAbstract:Abstract Molybdenum Powder is manufactured in a two step process starting from MoO 3 . The first step reduction of MoO 3 to MoO 2 is carried out in rotary calciners. Agglomeration of Powder occurs during this reduction stage resulting in several manufacturing issues. The evolution of Agglomeration during the reduction of MoO 3 was investigated in the current study. As-received MoO 3 and MoO 3 milled for 0.5 h were used as the starting Powders. The Powders were reduced at 550 °C, 650 °C and 750 °C in a hydrogen atmosphere. The starting and reduced Powders at various temperatures were analyzed using BET surface area, XRD, and SEM techniques. The surface area of the reduced Powders was monitored for quantifying the degree of Agglomeration. The surface area was found to be minimum for the samples reduced at 650 °C. SEM observations confirmed the Agglomeration of Powders during reduction process. XRD analysis showed complete reduction of MoO 3 to MoO 2 at 650 °C and 750 °C. The Agglomeration of the Powders was either due to melting of eutectic formed between MoO 3 and Mo 4 O 11 or due to partial melting of MoO 3 . The reduction of MoO 3 is recommended to be completed at a low temperature to prevent Agglomeration of the oxide Powders.
Hideyuki Yasuda - One of the best experts on this subject based on the ideXlab platform.
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microstructure and mechanical property of synthesized hydroxyapatite prepared by colloidal process
Biomaterials, 2000Co-Authors: Hideyuki Yasuda, S. Mahara, Yukichi Umakoshi, Satoshi Imazato, S. EbisuAbstract:Synthesized hydroxyapatite (HAp) was prepared by the colloidal process. Mixed slurry composed of 25 vol% HAp Powder and 75 vol% aqueous solution containing a small amount of polycarboxylic acid ammonium as dispersant was produced. Viscosity of the HAp slurry, microstructure and mechanical property of the synthesized HAp prepared by this process depends on the quantity of dispersant. A mainly uniform microstructure was obtained in both green and sintered HAp with 2 wt% dispersant by preventing the Agglomeration of Powder in the slurry. A homogeneous microstructure was maintained even after annealing at temperatures between 1200 and 1400 degrees C. Maximum bending strength of 88.5 MPa was also obtained at an optimum dispersant concentration.
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Microstructure and mechanical property of synthesized hydroxyapatite prepared by colloidal process.
Biomaterials, 2000Co-Authors: Hideyuki Yasuda, S. Mahara, Yukichi Umakoshi, Satoshi Imazato, S. EbisuAbstract:Abstract Synthesized hydroxyapatite (HAp) was prepared by the colloidal process. Mixed slurry composed of 25 vol% HAp Powder and 75 vol% aqueous solution containing a small amount of polycarboxylic acid ammonium as dispersant was produced. Viscosity of the HAp slurry, microstructure and mechanical property of the synthesized HAp prepared by this process depends on the quantity of dispersant. A mainly uniform microstructure was obtained in both green and sintered HAp with 2 wt% dispersant by preventing the Agglomeration of Powder in the slurry. A homogeneous microstructure was maintained even after annealing at temperatures between 1200 and 1400°C. Maximum bending strength of 88.5 MPa was also obtained at an optimum dispersant concentration.
Ravi K. Enneti - One of the best experts on this subject based on the ideXlab platform.
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Effect of ammonium dimolybdate (ADM) on the reduction of molybdenum trioxide
International Journal of Refractory Metals and Hard Materials, 2012Co-Authors: Ravi K. Enneti, Thomas A. WolfeAbstract:Abstract Ammonium dimolybdate ((NH 4 ) 2 Mo 2 O 7 ) or molybdenum trioxide (MoO 3 ) is used as starting raw materials for manufacturing Mo Powders. In the initial step, usually carried out in rotary calciners, (NH 4 ) 2 Mo 2 O 7 or MoO 3 is reduced to MoO 2 . Agglomeration of Powder due to melting of eutectic formed between MoO 3 and Mo 4 O 11 and due to melting of MoO 3 occurs during this reduction step resulting in several manufacturing issues. The reduction from (NH 4 ) 2 Mo 2 O 7 involves an endothermic reaction however, reduction of MoO 3 occurs only by exothermic reaction. It is hypothesized that addition of (NH 4 ) 2 Mo 2 O 7 to MoO 3 will decrease Agglomeration of Powders due to the endothermic reaction involved in the reduction process. The current paper details experiments carried out to verify the hypothesis. MoO 3 containing varying amounts (NH 4 ) 2 Mo 2 O 7 were reduced at 550 °C, 650 °C and 750 °C in hydrogen atmosphere. The results show lower Agglomeration of Powder with addition of (NH 4 ) 2 Mo 2 O 7 . The thermal analysis results confirm reduction of MoO 3 at lower temperatures with the addition of (NH 4 ) 2 Mo 2 O 7 .
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Agglomeration during reduction of MoO3
International Journal of Refractory Metals and Hard Materials, 2012Co-Authors: Ravi K. Enneti, Thomas A. WolfeAbstract:Abstract Molybdenum Powder is manufactured in a two step process starting from MoO 3 . The first step reduction of MoO 3 to MoO 2 is carried out in rotary calciners. Agglomeration of Powder occurs during this reduction stage resulting in several manufacturing issues. The evolution of Agglomeration during the reduction of MoO 3 was investigated in the current study. As-received MoO 3 and MoO 3 milled for 0.5 h were used as the starting Powders. The Powders were reduced at 550 °C, 650 °C and 750 °C in a hydrogen atmosphere. The starting and reduced Powders at various temperatures were analyzed using BET surface area, XRD, and SEM techniques. The surface area of the reduced Powders was monitored for quantifying the degree of Agglomeration. The surface area was found to be minimum for the samples reduced at 650 °C. SEM observations confirmed the Agglomeration of Powders during reduction process. XRD analysis showed complete reduction of MoO 3 to MoO 2 at 650 °C and 750 °C. The Agglomeration of the Powders was either due to melting of eutectic formed between MoO 3 and Mo 4 O 11 or due to partial melting of MoO 3 . The reduction of MoO 3 is recommended to be completed at a low temperature to prevent Agglomeration of the oxide Powders.
Marek Polanski - One of the best experts on this subject based on the ideXlab platform.
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the effects of ball milling and molar ratio of lih on the hydrogen storage properties of nanocrystalline lithium amide and lithium hydride linh2 lih system
Journal of Alloys and Compounds, 2010Co-Authors: R A Varin, M Jang, Marek PolanskiAbstract:Abstract High-energy ball milling was applied to the mixtures of LiNH 2 and LiH having the molar ratio 1:1, 1:1.2 and 1:1.4LiH. During a high-energy ball milling of the 1:1 molar ratio mixture the grain (crystallite) size of LiNH 2 and LiH constituent decreases monotonically with increasing milling time while the specific surface area (SSA) of Powder increases up to 25 h of milling duration and then decreases after milling for 100 h due to the excessive Agglomeration of Powder particles into lumps. A single-phase LiNH 2 decomposes through melting and the release of ammonia (NH 3 ). A just mixed LiNH 2 + LiH mixture still mostly decomposes through the melting of LiNH 2 and release of NH 3 . For the hydrogen to be effectively released from the mixture of (LiNH 2 + LiH) a high-energy ball milling is necessary which makes an intimate contact between both constituents. The activation energy for hydrogen desorption from the ball milled mixture of (LiNH 2 + LiH) decreases with increasing SSA of Powders up to ∼26 m 2 /g and then levels off with further increase of SSA. For the ball milled mixture of LiNH 2 :LiH the lowest activation energy is observed for the molar ratio of 1:1.2LiH. The hydrolysis/oxidation of the fraction of LiH into LiOH in the mixture makes a fraction of LiH inactive in the intermediate reaction NH 3 + LiH → LiNH 2 + H 2 and creates the major obstacle to the hydrogen desorption from the ball milled mixture of LiNH 2 + LiH. At the molar ratio 1:1.2 of LiNH 2 :LiH the mass of the active LiH is the largest one which leads to the largest quantity of desorbed hydrogen (∼5 wt.%). The amount of hydrogen desorbed from LiNH 2 + LiH slightly decreases with increasing milling time from 5 to 100 h due to the reduction in grain (crystallite) size of LiH which renders it more sensitive to hydrolysis and the formation of LiOH.
