FABRICATION OF POTASSIUM-SUBSTITUTED HYDROXYAPATITE CERAMICS VIA ULTRASONIC SPRAY-PYROLYSIS ROUTE

Abstract

Biological apatite presented in bone and teeth of mammals contains various ions, such as Na⁺, K⁺, Mg²⁺, F^- and CO₃^2- ions, in trace levels. Substitution of the above ions into hydroxyapatite (HAp) have great effect on the crystallinity, morphology, lattice parameters and stability of the apatite structure. It is known that potassium (K) in the living bone give a tremendous effect to the biomineralization process. Aim of this study is to clarify the influence of substitution of potassium into the HAp structure on the properties of powders and ceramics. In this study, we have fabricated the potassium-substituted hydroxyapatite (KAp) ceramics via an ultrasonic spray-pyrolysis route. Effect of potassium substitution on the phase, chemical composition, morphology and crystal lattice structure of HA was examined. Experimental results showed that the addition of potassium does not significantly affect the crystal phase, particle morphology and particle size. Sintered bodies fabricated from KAp powders were of single phase of HAp, and lattice constants of a-axis and c-axis increased with potassium contents. Substitution of potassium into the HAp lattice formed OH vacancies and caused grain growth.