Enthalpies of formation of lead zirconate titanate (PZT) solid solutions

Manisha V. Rane, Alexandra Navrotsky, George A. Rossetti

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


The formation energetics and heats of mixing of lead zirconate titanate (PZT) PbZrxTi1-xO3 solid solutions have been investigated using high-temperature oxide melt solution calorimetry. While the heat content (H973-H298) is almost constant (80-82 kJ/mol) for x = 0.15-1.0, its value for PbTiO3 (x = 0.0) is larger (86.15 ± 0.55 kJ/mol). Linear variation in the enthalpy of drop solution, ΔHds, and the enthalpy of formation from the oxides, ΔHf,ox (298K), is observed in the tetragonal region (0≤x≤ 0.5) and continues smoothly into part of the rhombohedral region (0.5≤x≤ 0.65). Fitting the data in the tetragonal phase region (0≤x≤ 0.5) to a straight line enables an extrapolation to give the heat of the virtual transformation PbTiO3 (tetragonal → orthorhombic) as 24.0 ± 3.9 kJ/mol. An extrapolation from the rhombohedral region gives 33.3 ± 3.6 kJ/mol for ΔH of the virtual transition PbZrO3 (orthorhombic or rhombohedral → tetragonal). The transition enthalpy between orthorhombic and rhombohedral PbZrO3 is zero within experimental error. The enthalpy of formation from the oxides, ΔHf, ox(298 K), varies from -36.7 ± 2.7 kJ/mol for PbTiO3 to 0.7 ± 4.3 kJ/mol for PbZrO3. The ΔHf,ox(973 K) values agree with previously reported ΔHf,ox values measured in alkali borate solvent at 1073 K. Fitting ΔHmix(973 K) to a regular solution model yields an interaction parameter, W, of 39.8 ± 4.6 kJ/mol. However, structural complexity makes the regular solution model only a crude physical description.

Original languageEnglish (US)
Pages (from-to)402-409
Number of pages8
JournalJournal of Solid State Chemistry
Issue number2
StatePublished - Nov 1 2001
Externally publishedYes


  • Calorimetry
  • Enthalpy of formation
  • Enthalpy of transition
  • Heat of mixing
  • PZT

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry


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