Stability of the low temperature polymorphs (y and α) of Lu-doped Y2Si2O7

The present study analyses the formation kinetics as well as the thermodynamic stability of the a and y polymorphs of Lu-doped Y2Si2O7. The analysis has been carried out by means of both in situ and ex situ diffraction experiments. Si-29 MAS-NMR spectroscopy has also been used to complement the information obtained from the diffraction measurements. The results indicate that both a and y polymorphs display the same temperature stability field (975 degrees C <= T < 1075 degrees C) although crystallization kinetics of a seems to be faster than that of y. (c) 2007 Published by Elsevier Ltd.