Structural properties and state of the surface layer of zirconium dioxide modified by tungstate anions

A tetragonal metastable phase of zirconium dioxide formed after the addition of tungstate anions (>13 mol %) to the hydroxide precursor by different methods with heating (600–700°C), as revealed by X-ray diffraction analysis and X-ray photoelectron and IR spectroscopy. The W⁶⁺ and W⁵⁺ cations formed a solid solution with ZrO₂. On the surface of the solid solution, the tungsten cations formed tungstate clusters (?WO _x ?)n. The formation of the WO₃ phase was observed at concentrations of tungstate anions higher than 17.6 mol % or at temperatures of 850–870°C.