Dielectric and piezoelectric properties of hydroxyapatite-BaTiO3 composites

This letter describes the relationships between the composition and the dielectric and piezoelectric properties of hydroxyapatite-barium titanate composites for polarized bone substitutes. The ac conductivity and permittivity were characterized from 0.1 Hz to 1 MHz, along with measurements of the d(33) piezoelectric charge coefficient. The addition of BaTiO3 led to an increase in permittivity and ac conductivity of the material. The increase in both properties was attributed to the presence of the high permittivity ferroelectric phase. The d(33) and g(33) coefficients decreased rapidly as hydroxyapatite was introduced into BaTiO3 material. Composites below 80% by volume of BaTiO3 exhibited no net piezoelectric effect. (c) 2006 American Institute of Physics.