Nanocrystallization of amorphous zirconia-germania mixed oxides prepared by sol–gel technique

The low-temperature preparation method based on organic-free sol–gel sequence has been elaborated for the binary oxide system ZrO2–GeO2. The coprecipitation method developed within the framework of the present work owing to the strong acid–base interaction of the components allowed to produce stable sols of the binary oxides with high dispersity and homogeneity. A usage of this method has extended the homogeneity range in the ZrO2–GeO2 system up to the molar ratio ZrO2–GeO2=24:76. A heat-treatment of ZrO2–GeO2 xerogels (dried in air sols) resulted in transformation of amorphous materials into homogeneous nanocrystalline glass-ceramic composition. The earlier crystallization steps were detected with XRD, DTA, and IR spectroscopy. ZrO2–GeO2 molar ratio was studied in the range 50:50<ZrO2–GeO2<24:76.