Structure and phase stability of the CdTiO3–PbTiO3 system

The formation of solid solutions in the CdTiO3–PbTiO3 system has been examined using x-ray diffraction (XRD) and differential scanning calorimetry. The XRD data showed two solid-solution ranges for the (Pb1−xCdx)TiO3 system at 1170 °C; orthorhombic on the cadmium-rich side and tetragonal on the lead-rich side, separated by a two-phase region for 0.08 10% increase in the c/a ratio, demonstrating that the role of Cd in this structure is quite unique. The enthalpy of the tetragonal-to-cubic phase transformation also increases with increasing Cd substitution, although the temperature of the transition is ∼20° lower than that found in pure PbTiO3.