TiO₂(B) nanocrystals in Ti-doped lithium aluminosilicate glasses

Highlights

• First evidence for the formation of the titania polymorph TiO₂(B) in a glass

• TiO₂(B) is the first crystal phase in ceramized LAS glasses with titania as nucleating agent.

• TiO₂(B) transforms to anatase upon ceramming at higher temperatures and for longer times.

Abstract

Three different compositions of TiO₂-doped lithium aluminosilicate glass were annealed and analyzed to investigate their first stages of crystallization. After phase separation had occurred, monoclinic TiO₂(B) was invariably observed as the first seed forming phase. Phase identification was confirmed by Raman spectroscopy and transmission electron microscopy, disproving its interpretation as pseudobrookite in previous literature sources. The phase was observed to undergo gradual transformation into anatase with increasing temperature, but its persistence was longer in the Si-richer samples. It disappeared right before the volume crystallization of high quartz solid solution and keatite solid solution.