Li2O . 7GeO2 gel was synthesized by the hydrolytic polycondensation reactions of germanium ethoxide with lithium methoxide. The crystallization behaviour of the gel, examined by differential thermal analysis and X-ray diffraction, is reported and discussed. Lithium heptagermanate gel was found to crystallize in two steps. In the primary transformation, microcrystallites of Li2Ge7O15 are crystallized in an amorphous matrix. In the second transformation, well-shaped Li2Ge7O15 crystals are formed. The activation energy values for the two stages are found to be 589 and 495 kJ mol-1, respectively. The results are compared with those obtained for conventional lithium heptagermanate glass.
Gel Synthesis and Crystallization of Li2O.7GeO2 Glass Powders / Aronne, Antonio; M., Catauro; Pernice, Pasquale; A., Marotta. - In: THERMOCHIMICA ACTA. - ISSN 0040-6031. - STAMPA. - 216:(1993), pp. 169-176. [10.1016/0040-6031(93)80390-V]
Gel Synthesis and Crystallization of Li2O.7GeO2 Glass Powders
ARONNE, ANTONIO;PERNICE, PASQUALE;
1993
Abstract
Li2O . 7GeO2 gel was synthesized by the hydrolytic polycondensation reactions of germanium ethoxide with lithium methoxide. The crystallization behaviour of the gel, examined by differential thermal analysis and X-ray diffraction, is reported and discussed. Lithium heptagermanate gel was found to crystallize in two steps. In the primary transformation, microcrystallites of Li2Ge7O15 are crystallized in an amorphous matrix. In the second transformation, well-shaped Li2Ge7O15 crystals are formed. The activation energy values for the two stages are found to be 589 and 495 kJ mol-1, respectively. The results are compared with those obtained for conventional lithium heptagermanate glass.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
