The aluminium effect on the phospho-silicate materials

Because of the noted phase separation in phospho-silicate materials with sodium and calcium the attempt of homogenization by the addition of aluminium. has been undertaken. Constant amount of aluminium equal to 5 mol% of AlPO4 was added whereas the proportion of NaCaPO4/SiO2 was changed. X-ray diffraction (XRD) measurements made it possible to identify amorphous and crystalline samples. The amount of crystalline phases in comparison with the analogous NaCaPO4-SiO2 materials decreased. We used energy-dispersive X-ray analysis (EDX) to evaluate chemical composition and scanning electron microscopy (SEM) to find out the chemical elements distribution. It was found that the addition of aluminium caused more uniform distribution of all elements. Fourier transform infrared spectroscopy (FTIR) measurements as well as computer decomposition of the obtained spectra into component bands were performed. The decomposition made it possible to connect bands with the groups of phospho-oxygen, silico-oxygen and lattice vibrations. (C) 2002 Elsevier Science B.V. All rights reserved.