Structure and Thermal Stability of Lithium-Substituted Hydroxyapatite Ceramics

— We have studied the effect of doping with lithium cations on the phase composition, lattice parameters, and crystallite size of hydroxyapatite at different heat treatment temperatures (900, 1200, and 1400°C). The results demonstrate that, at high degrees of substitution (20 mol %) and heat treatment temperatures of 1200 and 1400°C, lithium cations contribute to conversion of apatite into lithium-substituted tricalcium phosphate. At degrees of substitution of 1, 5, and 10 mol %, the addition of lithium causes no destabilization of the apatite structure even at a temperature of 1400°C.