Structure and Properties of Rapidly Quenched Li2O‐Al2O3‐Nb2O5 Glasses

Abstract

In the system Li2O‐A12O3‐Nb2O5, glasses were prepared in a wide range of compositions using a twin‐roller quenching technique. The glass‐transition temperature, ranging from 495° to 780°C, was primarily determined by the Li2O content and was independent of the Al2O3 and Nb2O5 contents in the composition region with the Li2O/Nb2O5 ratio smaller than unity, whereas it increased with the replacement of Nb2O5 by A12O3 in the region of the ratio larger than unity. Although the conductivity, ranging from 10‐9 to 10‐5Ω‐1 cm‐1 at 500 K, was also primarily determined by the Li2O content, it tended to decrease slightly as Nb2O5 was replaced by A12O3 in glasses containing a given Li2O5 content; such a tendency was pronounced in the composition region with the Li2O/Nb2O5 ratio larger than unity. Ir spectra and the chemical shifts of AIKα X‐ray fluorescence lines of the glasses revealed that aluminum ions in the glasses with the Li2O/Nb2O5 ratio smaller than unity were mainly in the octahedral coordination state, Aloe, and that, when the ratio exceeded unity, the amount of the tet‐rahedrally coordinated aluminum ions AlO4 increased with increasing Li2O/Nb2O5 ratio.