Synthesis of Hydroxyapatite Powders by Homogeneous Precipitation Method and Their Thermal Changes

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J. Korean Ceram. Soc. > Volume 33(1); 1996 > Article

Journal of the Korean Ceramic Society 1996;33(1): 7.

균일침전법을 이용항 Hydroxyapatite 분말의 제조 및 가열변화

이진호, 박훈, 김창은

연세대학교 세라믹공학과

Synthesis of Hydroxyapatite Powders by Homogeneous Precipitation Method and Their Thermal Changes

ABSTRACT

${CO_3}^{2-}$ containing whisker-like hydroxyapatite powders were synthesized byhomogeneous precipitation method using urea, Dicalcium phosphate anhdrate[DCPA; $CaHPO_4$] and octacalcium phosphate [OCP; $Ca_8H_2(PO_4_)6cdot5H_20$]were obtained as precursors and they transformed to high crystalline hydroxyapatites at pH 5.62, and 6.54 respectively. According to the condition of the final pH in the solutions for the solution products and urea contents OCP was remained. When the solution product of $Ca^{2-}$ and ${PO_4}^{3-}$ was $1.5times 10^4$[$mM^2$] and the content of urea was 0.25 mol.$dm^{-3}$ well crystallized whisker-like hydroxyapatite tens of micrometer in length was obtained. By heat treatment DCPA and OCP were decomposed into $beta$-tricalcium phosphate [$beta$-TCP ; $beta$-$Ca_3{PO_4}_2$] and $beta$-dicalcium phosphate [$beta$-DCP ;$beta$-$Ca_2P_2O_4}_2$]. And well-crystallized hydroxyapatite was partially decomposed into $beta$-TCP at $800^{circ}C$.

Key words: Homogeneous precipitation method, Hydroxyapatite, pH, DCPA, OCP, Whisker