Calcium tetragermanate and calcium digermanate glasses were prepared and studied with the aid of differential thermal analysis, X-ray diffraction and FTIR spectroscopy. The molar ratio of GeO6/GeO4 groups increases with the CaO/GeO2 molar ratio. A two steps crystallisation process was found: initially microcrystals are formed that at higher temperatures are transformed in well shaped crystals. An unidentified phase crystallises in both glasses. CaGe2O5 crystals also grow in calcium digermanate glass. The influence of the specific surface area of the glass sample and of a heat treatment of nucleation was pointed out. The activation energy for crystal growth in each glass was evaluated by a non isothermal method
BULK NUCLEATION AND CRYSTAL GROWTH IN CALCIUM TETRA AND DIGERMANATE GLASSES
CATAURO, Michelina;
1998
Abstract
Calcium tetragermanate and calcium digermanate glasses were prepared and studied with the aid of differential thermal analysis, X-ray diffraction and FTIR spectroscopy. The molar ratio of GeO6/GeO4 groups increases with the CaO/GeO2 molar ratio. A two steps crystallisation process was found: initially microcrystals are formed that at higher temperatures are transformed in well shaped crystals. An unidentified phase crystallises in both glasses. CaGe2O5 crystals also grow in calcium digermanate glass. The influence of the specific surface area of the glass sample and of a heat treatment of nucleation was pointed out. The activation energy for crystal growth in each glass was evaluated by a non isothermal methodI documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
