Synthesis and structure of cerium-substituted hydroxyapatite.

The aim of this study was to explore the effect of cerium ions on the formation and structure of hydroxyapatite (HAP). All particles, prepared by hydrothermal method, were synthesized at varied X(Ce) = Ce/(Ca + Ce) (from 0 to 10%) with the atomic ratio (Ce + Ca)/P fixed at 1.67. Their morphology, composition and crystal structure were characterized by TEM, EPMA, XRD and FTIR. The results showed that in this composition range the apatite structure is maintained, Ce3+ ions could enter the crystal lattice of apatite and substitute Ca2+ ions. The doping of Ce3+ ions resulted in the decrease of the crystallite size with increase in X(Ce). The HAP particles without doping were short rods having a diameter from 10 to 20 nm and a length from 30 to 50 nm. They grew into long needles upon increasing X(Ce).