Synthesis of monoclinic celsian from seeded alkoxide gels

Abstract

Celsian gels seeded with fine monoclinic celsian seeds were prepared by an all-alkoxide gel route and the effect of seeding on crystallization of the gel-derived glass examined. Gels seeded with 10 wt.% of fine crystals sintered to greater than 93% and 95% density in the form of cold pressed gel powder pellets and as bulk gel respectively, when sintered at temperatures below 1050°C. XRD analysis indicated that seed facilitated the formation of monoclinic celsian in the densified celsian glass, and the amount of monoclinic celsian formed increased with increasing seed content. 92% of the glass crystallized into monoclinic celsian when 10% of 3.2 μm seeds were introduced. Transmission Electron Microscopy revealed epitaxial growth of monoclinic celsian from the crystal seeds but homogeneous nucleation and growth of hexacelsian.