Fully densified zircon co-doped with iron and aluminium prepared by sol–gel processing

A sol–gel technique has been used to prepare Fe and Al doped zircon. Structural properties have been studied by X-ray diffraction, nuclear magnetic resonance, scanning electron microscopy and transmission electron microscopy (TEM). Fully densified zircon was produced with high zircon yield and promising microstructures. The presence of Fe promotes zircon formation, while Al improves densification. The zircon phase starts to form at 1215 °C, with almost single phase zircon obtained at 1400 °C when heated for 1 h. Densification increases very significantly (to 99.7% of theoretical density) when the holding time was increased to 48 h from 1 h. TEM micrographs reveal a crystalline grain boundary phase containing some Fe and Al.