Crystallization behaviour of the series of solid solutions ZrxTi1−xO2 and PbyZrxTi1−xO2+y prepared by the sol-gel process

A series of solid solutions of zirconium titanium oxide Zr x Ti 1–x O 2 (0≤x≤1) and Pb y Zr x Ti 1–x O 2+y (0≤y≤1.15, 0≤x≤1) up to lead zirconate titanate PbZr x Ti 1–x O 3 was prepared from zirconium and titanium n-propoxide and lead acetate, dissolved in 2-methoxyethanol, by the sol-gel process. The crystallization was investigated by differential thermal analysis (DTA), and the apparent activation energies, crystallization enthalpies and Avrami exponents were determined. The crystalline phases were identified by X-ray diffraction (XRD). Within the series of solid solutions Zr x Ti 1–x O 2 , the activation energy changes from ca. 200 kJ mol –1 for samples with low (x≤0.14) or high (x≥0.9) ZrO 2 content, to ca. 800 kJ mol –1 for intermediate ZrO 2 contents. Within the series of solid solutions Pb y Zr x Ti 1–x O 2+y , PbO lowers the activation energies and hinders the crystallite growth.