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

Abstract

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.