Microstructure and mechanical property of synthesized hydroxyapatite prepared by colloidal process.

Synthesized hydroxyapatite (HAp) was prepared by the colloidal process. Mixed slurry composed of 25 vol% HAp powder and 75 vol% aqueous solution containing a small amount of polycarboxylic acid ammonium as dispersant was produced. Viscosity of the HAp slurry, microstructure and mechanical property of the synthesized HAp prepared by this process depends on the quantity of dispersant. A mainly uniform microstructure was obtained in both green and sintered HAp with 2 wt% dispersant by preventing the agglomeration of powder in the slurry. A homogeneous microstructure was maintained even after annealing at temperatures between 1200 and 1400 degrees C. Maximum bending strength of 88.5 MPa was also obtained at an optimum dispersant concentration.