Host: The Ceramic Society of Japan
Effect of colloidal silica addition on the formation of porous spherical a -calcium orthophosphate (a -Ca3(PO4)2 ; a - TCP) agglomerates was examined in this research. The aqueous solutions containing the solution with 1.8 mol·dm-3 Ca(NO3)2, 1.2 mol dm-3 (NH4)2HPO4 and 0 ~ 0.4 mass% colloidal silica (primary particle size: 14 ~ 55 nm) were spray-pyrolyzed at 600ºC. After the solution containing colloidal silica (primary particle size: 24 nm) was spray-pyrolyzed at 600ºC, the resulting powder was further heat-treated at 1200ºC for 10 min. The crystalline phase of resulting powder was only a -TCP. This powder contained hollow spherical agglomerates with diameters of 1 ~ 11 um. After the calcium phosphate paste (CPP) with 50 mass% a -TCP was immersed into the simulated body fluid at 37 ºC for 7 d, the compressive strength was reduced down to 20 MPa, due to the increased porosity.
