TY - JOUR
T1 - Fabrication of hydroxyapatite with controlled morphology in a micro-reactor
AU - Fujii, Eiji
AU - Kawabata, Koji
AU - Nakazaki, Yoshiaki
AU - Tanizawa, Yuji
AU - Shirosaki, Yuki
AU - Hayakawa, Satoshi
AU - Osaka, Akiyoshi
N1 - Copyright:
Copyright 2018 Elsevier B.V., All rights reserved.
PY - 2011/2
Y1 - 2011/2
N2 - A flow-micro-reactor system was employed to fabricate hydroxyapatite (HAp) in order to mimic the interface between calcium and phosphate solutions on a wet chemical procedure. The mixing ratioof calcium nitrate tetrahydrate and diammonium hydrogenphosphate solution was set to the stoichiometric atomic ratio HAp, 1.67, whilepH value of the product suspension was varied from 6.4 to 10.0. The product morphology was changed from nano-sheet type to nano-particle type via nano-rod one, while theirsize was decreased from 100-500 nm to 50 nm. All as-prepared samples, irrespective of pH value of the resultant suspension, consisted of HAp, predominant phase, octacalcium phosphate (OCP), and dicalcium phosphate dihydrate (DCPD) or dicalcium phosphate anhydrate (DCPA). A batch system using the same solutions yielded very similar results, which confirmed that the reactions inthismicro-reactor well reproduced a large-scalemixing system. Calcining sample obtained from pH 6.4 suspension for 2h at lower temperatures (<400°C) lead to decomposition of DCPD, DCPA, and OCP. Trace tricalcium phosphate (TCP) appeared on calcination above 400°C. HAp remained the predominant phase throughout the process. After calcination at 600°C, no other phases than HAp and TCP were present in the product. The analyzed ratioCa/P (1.38) implied that those crystalline phases were highly Ca-deficient, and that amorphous calcium phosphates were involved in both as-prepared and calcined sample pH 6.4.
AB - A flow-micro-reactor system was employed to fabricate hydroxyapatite (HAp) in order to mimic the interface between calcium and phosphate solutions on a wet chemical procedure. The mixing ratioof calcium nitrate tetrahydrate and diammonium hydrogenphosphate solution was set to the stoichiometric atomic ratio HAp, 1.67, whilepH value of the product suspension was varied from 6.4 to 10.0. The product morphology was changed from nano-sheet type to nano-particle type via nano-rod one, while theirsize was decreased from 100-500 nm to 50 nm. All as-prepared samples, irrespective of pH value of the resultant suspension, consisted of HAp, predominant phase, octacalcium phosphate (OCP), and dicalcium phosphate dihydrate (DCPD) or dicalcium phosphate anhydrate (DCPA). A batch system using the same solutions yielded very similar results, which confirmed that the reactions inthismicro-reactor well reproduced a large-scalemixing system. Calcining sample obtained from pH 6.4 suspension for 2h at lower temperatures (<400°C) lead to decomposition of DCPD, DCPA, and OCP. Trace tricalcium phosphate (TCP) appeared on calcination above 400°C. HAp remained the predominant phase throughout the process. After calcination at 600°C, no other phases than HAp and TCP were present in the product. The analyzed ratioCa/P (1.38) implied that those crystalline phases were highly Ca-deficient, and that amorphous calcium phosphates were involved in both as-prepared and calcined sample pH 6.4.
KW - Calcium phosphate
KW - Hydroxyapatite
KW - Micro-reactor
KW - Nano-sheet
KW - Spherical particle
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U2 - 10.2109/jcersj2.119.116
DO - 10.2109/jcersj2.119.116
M3 - Article
AN - SCOPUS:79551677545
VL - 119
SP - 116
EP - 119
JO - Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan
JF - Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi/Journal of the Ceramic Society of Japan
SN - 1882-0743
IS - 1386
ER -