Low‐Temperature Phase Relationships in the System ZrO ₂ ‐TiO ₂

The phase relationships in the system ZrO 2 ‐TiO 2 near the compound ZrTiO 4 have been clarified through an experimental study involving the characterization of both single‐crystal and powder specimens, the latter prepared through conventional solid‐state reaction and also by low‐temperature co‐precipitation methods. Zr 1+ x Ti 1‐ x O 4 (1/10 > x >‐1/6), having the α‐PbO 2 ‐type structure, is found to transform on cooling between ∼1100° and ∼1150°C. Below this temperature there is an unusual, continuous phase transition leading to the formation of the stable low‐temperature phase ZrTi 2 O 6 . Low‐level doping with Y 2 O 3 was found to enhance apparent cation ordering in intermediate compositions in the temperature range just below the phase transition.