Characterization of 50wt%SiO2-20wt%P2O5-30wt%CaO Glass-ceramic Powders Prepared by the Sol-gel Process

Abstract

Glass-ceramic powders with the oxide batch formulation 50wt%SiO2, 20wt%P2O5 and 30wt%CaO were prepared by the sol-gel process using tetraethoxysilane, calcium nitrate and phosphoric acid as raw materials. The obtained gels and powders were characterized by TG-DTA thermal analysis, FTIR analyses and XRD measurements. The results indicated that (1) heating to more than 600°C brought about elimination of -OC2H5 side chains from gels, and formation of a SiO2-based glass network, (2) crystallization such as Ca3(PO4)2 notably occurred in the SiO2-based glass matrix when heated to more than 900°C, (3) -OH groups existed on SiO2-based glass-ceramic surfaces in the temperature region less than 900°C, and (4) the melting point of this composition was more than 1400°C. This study suggests that sol-gel-derived SiO2-based glass-ceramic powder containing P and Ca might be useful as bioactive implant materials.