EFFECTS OF VARIOUS METAL-OXIDE ADDITIONS ON SINTERING OF β-CALCIUM ORTHOPHOSPHAPIE PREPARED BY SPRAY-PYROLYSIS

Effects of various metal-oxide additions on sintering of β-calcium orthophosphate (β-Ca3(PO4)2) were examined. The metal-oxide additives used in this experiment were: (i) the monovalent metal oxides Li2O, Na2O and K2O; (ii) the divalent metal oxides MgO, CaO, SrO and BaO; (iii) trivalent metal oxides Al2O3 and Fe2O3; (iv) tetravalent metal oxides SiO2, TiO2 and ZrO2. The sintering of β-Ca3(PO4)2 was promoted only by the addition of Fe2O3; the relative density of the sintered compact with 10mol% of Fe2O3 addition fired at 1070°C for 5 h attained 98.7%.