• Proceedings of the Korean Fiber Society Conference
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• 2007.11a
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• pp.509-510
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• 2007

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• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.311-320
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• 1990

Hydroxyapatite powders were synthesized with Ca/P=1.67, 1.70 and pH=7, 11 by precipitation method and fluorine substituted hydroxyapatite ceramics were prepared using these powders. After characterization of these hydorxyapatite bioceramics, chemical bonding between these sepcimens in simulated body fluid was investigated. Bysubstitution of 7.5% of fluorine, hydroxyapatite was prevented to decompose into β-tricalcium phosphate and its sintered density and mechanical strength were increased. The bending strength of these hydroxyapatite ceramics was 137MPa. The hydroxyapatite ceramics chemically bonded each other in Ringer's solution and the component of bonded layer was also hydroxyapatite.

• Korean Journal of Materials Research
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• v.17 no.10
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• pp.544-547
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• 2007

Human teeth were scratched by the abrasive paper, dropping in hydroxyapatite solution during 1, 2, 3, 4 months. We studied teeth surface change with SEM each months. After 1 months treatment the surface appeared the change. Because of the hydroxyapatite ion exchange mechanism. The scratched surface was recovered by the hydroxyapatite. The results of EDS showed that $Ca^{2+}$ ion and $PO_4^{3-}$ ion were removed from hydroxyapatite solution to scratched teeth surface.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.2
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• pp.79-85
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• 2005

Commercial hydroxyapatite (HA) powders were calcined at the temperature range of $1000{\sim}1350^{\circ}C$ in air, for 2h, and the calcined powders were immersed in simulated body fluid (SBF) of pH 7.4 at $37^{\circ}C$ for 3 or 7 days. Thermal decomposition and their related dissolution behaviors of hydroxyapatite were investigated by XRD, FT-IR, and TEM. At the temperature of $1200^{\circ}C$, HA gradually releases its $OH^-$ ions and transforms to OHAP((oxyhydroxyapatite, ($Ca_{10}(PO_4)_6O_x(OH)_{2-2x}$)). HA thermally decomposes to ${\alpha}-TCP$ (${\alpha}-tricalcium$ phosphate) and TTCP (tetracalcium phosphate) phase at $1350^{\circ}C$. It was found that the surface dissolution of the hydroxyapatite powders was accelerated by non-stoichiometric composition and decomposed to ${\alpha}-TCP$ and TTCP.