Chemical Interactions Promoting the ZrO 2 Tetragonal Stabilization in ZrO 2 –SiO 2 Binary Oxides

Metastable tetragonal ZrO 2 phase has been observed in ZrO 2 –SiO 2 binary oxides prepared by the sol–gel method. There are many studies concerning the causes of ZrO 2 tetragonal stabilization in binary oxides such as Y 3 O 2 –ZrO 2 , MgO–ZrO 2 , or CaO–ZrO 2 . In these binary oxides, oxygen vacancies cause changes or defects in the ZrO 2 lattice parameters, which are responsible for tetragonal stabilization. Since oxygen vacancies are not expected in ZrO 2 –SiO 2 binary oxides, tetragonal stabilization should just be due to the difficulty of zirconia particles growing in the silica matrix. Furthermore, changes in the tetragonal ZrO 2 crystalline lattice parameters of these binary oxides have recently been reported in a previous paper. The changes of the zirconia crystalline lattice parameters must result from the chemical interactions at the silica–zirconia interface (e.g., formation of Si–O–Zr bonds or Si–O − groups). In this paper, FT‐IR and 29 Si NMR spectroscopy have been used to elucidate whether the presence of Si–O–Zr or Si–O − is responsible for tetragonal phase stabilization. Moreover, X‐ray diffraction, Raman spectroscopy, and transmission electron microscopy have also been used to study the crystalline characteristics of the samples.