Influence of Lithium on the Structure and Phase Composition Formation in the Synthesis of Hydroxyapatite

Abstract

The influence of lithium substitution for calcium over a broad concentration range (0–20 mol %) on the crystal lattice parameters, coherent scattering regions, and phase composition was studied for hydroxyapatite synthesized by precipitation from solutions and heat treatment at 900, 1200, and 1400°C. The lithium substitution in a more than 10 mol % concentration and increase in the heat treatment temperature to 1400°C give rise to a complex phase composition, which includes not only the apatite phase, but also two tricalcium phosphate phases and calcium pyrophosphate. The results are useful for the development of hydroxyapatite-based materials for bone surgery.