Sol-gel derived P2O5-doped cordierite powders: characterization and phase transformation

The application of cordierite glass-ceramics as electronic materials has be en studied extensively because of their excellent dielectric properties. In this study, stoichiometric and P2O5-doped cordierite powders were synthesi zed by sol-gel method. The effect of P2O5 additive on the crystallization a nd phase tansformation was investigated using differential thermal analysis (DTA), infrared spectroscopy (IR) and X-ray diffraction (XRD. The activati on energies for mu -cordierite to alpha -cordierite transition with various additive concentrations were obtained using Kissinger equation. It was fou nd that P2O5 promotes the mu -cordierite to cr-cordierite transition at low additive concentrations, while it plays a non-steady inhibitory role at hi gher concentrations. IR spectra and XRD results revealed the presence of fa rringtonite at lower P2O5 additive concentrations and magnesium pyrophospha te at the higher concentrations, which lead to the increment of activation energies. (C) 2001 Elsevier Science Ltd. All rights reserved.