Zirconia as a Nucleating Agent in a Yttria-Alumina-Silica Glass

摘要

The crystallization behaviour of a ZrO_2-containing glass and a ZrO_2-free glass in the Y_2O_3-Al_2O_3-SiO_2 system prepared at 1700℃ were compared in order to study the influence of ZrO_2 on the nucleation and growth processes. Techniques used included SEM, DTA and XRD analysis. The microstructural development of the ZrO_2-containing material during crystallization was more complex than that of the ZrO_2-free material. In the crystallization treatments no phase separation prior to crystallization could be observed and no precursor crystalline phase was observed to form in the ZrO_2-containing glass. Thus the added zirconia could be considered to act as a growth modifier rather than a catalyst nucleating agent.