Application of Raman spectroscopy to the study of the phase composition ofphosphate based glass-ceramics

Porous glass-ceramics prepared by crystallization of 6Li(2)O.24TiO(2).39CaO .31P(2)O(5) glasses and acid leaching of soluble phases were characterized by powder X-ray Diffractometry, Infrared and Raman Spectroscopies. X-ray di ffractometry indicated that LiTi2(PO4)(3) and beta -Ca-3(PO4)(2) are major crystalline phases before acid leaching and that beta -Ca-3(PO4)(2) is remo ved during this treatment. In Raman spectra, the most noticeable change obs erved upon acid leaching is the disappearance of a band at 742 cm(-1), whic h cannot be assigned to beta -Ca-3(PO4)(2). It is evident from this observa tion that the ceramics contain additional phases not detected by X-ray diff ractometry. beta -Ca2P2O7 and Li(TiO)PO4 are proposed here as additional ph ases, on the basis of vibrational data. (C) 2001 Elsevier Science Ltd. All rights reserved.