Synthesis and dissolution behavior of β-TCP and HA/β-TCP composite powders

Calcium phosphate powders, beta-TCP and biphasic HA/beta-TCP, were synthesized by calcining the powders obtained from the coprecipitation method using Ca(NO3)(2)(.)4H(2)O and (NH4)(2)HPO4. The effects of the initial Ca/P ratio and pH of the solution on the phase evolution and in vitro dissolution behavior of the powders in a Ringer's solution were investigated. The Ca/P ratio of the resulting powders was strongly dependent on the pH of the solution and weakly dependent on the initial Ca/P ratio. Single phase TCP powder was obtained at pH = 7.4 and the initial Ca/P ratio had a little effect on the resulting Ca/P ratio. Biphasic composite powders were prepared at pH = 8.0 and the Ca/P ratio of resulting powder was controllable by adjusting the initial Ca/P ratio. TCP powder showed the highest dissolution rate in the Ringer's solution and biphasic composite powder exhibited an intermediate dissolution behavior between that of HA and TCP. (C) 2002 Elsevier Science Ltd. All rights reserved.