Structural examinations of gel-derived materials of the CaO-P2O5-SiO2 system

The effect of the different CaO and P2O5 precursors on the formation of gel-derived materials of CaO-P2O5-SiO2 System as well as on the structure of these materials was determined. As the substrates introducing the particular oxides the following materials were used: Si(OC2H5)(4) (TEOS); Ca(NO3)(2)4H(2)O; Ca(OOCCH3)(2)H2O; CaO dissolved in ethylene glycol, Ca dissolved in methoxyethanol, OP(OC2H5)(3), H3PO4, P2O5 dissolved in izopropanol or izobutanol or methoxyethanol. The obtained gels were dried and heated up to the following temperatures: 200, 400, 600, 800 and 1000 degrees C, Dried gels and gels after thermal treatment were examined by the X-ray diffraction spectroscopy. It has been found that the kind of CaO and P2O5 precursors influences the progress of gel polymerisation as well as the ability of gels to crystallise and the type of crystallising phases, (C) 1999 Elsevier Science B.V. All rights reserved.