Atomic ordering in xZrO₂·(1-x) SiO₂ xerogels (x=0.3, 0.5) by X-ray diffraction and reverse Monte Carlo simulations

Atomic distribution functions for xZrO₂·(1-x) SiO₂ xerogels (x=0.3, 0.5) have been obtained by X-ray diffraction experiments. Three dimensional structure models that closely reproduce the experimental structural data have been constructed by reverse Monte Carlo simulations. The model results suggest that the investigated xerogels do not exhibit any characteristics of a phase segregation and have a homogeneous structure at the atomic scale. In particular, the local atomic ordering in 0.5ZrO₂·0.5SiO₂ xerogels heat treated to 770 K has been found to be similar to that in crystalline ZrSiO₄. The question as to why a phase segregation occurs on the crystallization of xZrO₂·(1-x)SiO₂ xerogels (x-0.3, 0.5) has been addressed.