The influence of Na+ and Ca2+ ions on the SiO2-AlPO4 materials structure -: IR and Raman studies

The series of samples containing 0-20 mol% of NaCaPO4 and 20-0 mol% of AlPO4, respectively, with the constant amount Of SiO2 (80 mol%) have been selected. The materials were prepared using both sol-gel as well as aerosil pseudo-aqua solution method. The AlPO4. SiO2 and NaCaPO4. SiO2 (80 mol% of SiO2) samples have been prepared. IR and Raman spectra of these samples are presented. The spectra of materials from NaCaPO4-AlPO4-SiO2 system are compared to those of NaCaPO4. SiO2 and AlPO4. SiO2 sample (samples without Al3+ or Na+ and Ca2+ cations, respectively). The studies have enabled us to identify the bands arising from the internal and lattice vibrations. The slight differences between the spectra of sol-gel and aerosil pseudo-aqua solution materials are pointed out and discussed. The influence of Na+ and Ca2+ ions on the AlPO4-SiO2 materials structure is analysed. (C) 2001 Elsevier Science BN. All rights reserved.