An X-ray diffraction and NMR study into the mechanism of zircon formation from aqueous sols

Solid solutions of the formula Zr1-xSixO2 (x=0-0.5) were produced by an aqueous inorganic set-gel route. X-ray diffraction and solid state magic-angle spinning-nuclear magnetic resonance (MAS-NMR) were used to characterize the products at various calcination temperatures. The solubility limit of silica in zirconia at <950 degrees C was found to be similar to x=0.15 and that this amount stabilized the tetragonal zirconia phase to higher temperatures and inhibited the formation of zircon. With x=0.5, zircon formation was 70% at only 1100 degrees C.