Production of Sheet-Like Hydroxyapatite Particles Using a Microreactor

Abstract

Abstract Calcium hydroxyapatite (Hap) particles were produced using a microreactor, and the relationship between the morphology of the Hap particles and the synthesis conditions using a microreactor was investigated. Sheet-like Hap particles could be produced continuously using a microreactor, whereas only rod-like Hap particles were produced by a batch method. The Ca/P atomic ratio of the Hap particles produced by microreactor processing was 1.40–1.46, which was lower than the stoichiometric value of 1.67. This result suggests that the Hap particles produced by microreactor processing were calcium-deficient. The size of the sheet-like Hap particles increased, and the length of b and c axes of the Hap particles increased as the mixing efficiency of the microreactor increased, whereas the length of a axis remained almost unchanged. The X-ray diffraction patterns revealed that the lattice constant of the c axis increased while that of the a axis decreased as the mixing efficiency of the microreactor increased and they came close to data reported in a previous study. The size and shape of Hap particles produced by microreactor processing significantly depend on the mixing efficiency of the microreactor.