Preparation and dielectric property of sintered monoclinic hydroxyapatite

A preparation method of sintered monoclinic hydroxyapatite, Ca10(PO4)6(OH)2 is presented and its dielectric properties at various temperatures and/or frequencies are discussed. Sintered monoclinic hydroxyapatite showed two dielectric-loss peaks which can be attributed to reorientation of hydroxyl ions and defects of hydroxyl ions due to formation of oxyapatite. A dielectric anomaly at 483 K was observed, being consistent with the phase transition that change the hydroxyl dipole moments; the hydroxyl dipole moment is ordered at temperature lower than 483 K and that is disordered at temperatures higher than 483 K.