Electrical Polarization of β-Tricalcium Phosphate Ceramics

The beta-tricalcium phosphate (beta-TCP)-sintered pellets and powders were prepared and the ability of beta-TCP to store an electrical charge by electrical polarization was studied. The prepared beta-TCP was characterized by X-ray diffractometry and Fourier transform infrared spectroscopy. Alternating-current impedance conductivity and the energy of activation required for the ionic migration of beta-TCP were calculated. After electrical polarization of synthesized beta-TCP, the thermally stimulated depolarization current was measured, and the total stored charges in the samples were calculated. The energy of activation for the relaxation of electrical polarization in the synthesized beta-TCP pellets and powders approximated the energy of activation required for ionic migration in the beta-TCP pellets. It was confirmed that beta-TCP has a suitable composition and structure for ion conduction and a large electrical charge is stored in both the beta-TCP pellets and powders. Instead of proton transport polarization in hydroxyapatite, other charge carrier, such as Ca2+ or O2-, is assumed in beta-TCP, in which proton is not contained.