SINTERABILITY OF BETA-CALCIUM ORTHOPHOSPHATE POWDER PREPARED BY SPRAY-PYROLYSIS

Mixed solutions of Ca(NO3)2 and (NH4)2HPO, with Ca/P = 1.50 were spray -pyrolyzed at 600-degrees-C to produce beta-calcium orthophosphate (be ta-Ca3(PO4)2) powder; the spray-pyrolyzed powder was ground and then c alcined at 600-degrees-C for 1 h. The best crystalline beta-Ca3(PO4)2 powder was obtained from the solution with 1.80 mol.L-1 Ca(NO3)2, 1.20 mol.L-1 (NH4)2HPO4. The resulting powder was composed of primary part icles with sizes of <0.5 mum. Dense beta-Ca3(PO4)2 ceramics with a rel ative density of 96.1% could be fabricated by firing this compressed p owder at 1070-degrees-C for 5 h.