The PZT system (PbTixZr1−xO3, 0≤x≤1.0): High temperature X-ray diffraction studies. Complete x-T phase diagram of real solid solutions (Part 3)

• Published in: Ceramics international Vol. 39; no. 3; pp. 2889 - 2901
• Main Authors: Andryushina, I.N., Reznichenko, L.A., Shilkina, L.A., Andryushin, K.P., Dudkina, S.I.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-04-2013
• Subjects: D. PZT; High temperature; Homogeneity regions; Phase diagram; High temperature; D. PZT; Phase diagram; Homogeneity regions
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2012.09.063

Based on high temperature x-ray diffraction studies of the PZT system (PbTixZr1−xO3, 0.0≤x≤1.0) the complete x-T phase diagram of solid solutions is built, which exhibits peculiar properties due to the real structure of ceramics:
-irregularity of the phase transition line to the paraelectric state, which is more pronounced in the rhombohedral–tetragonal transition region;-appearance of intermediate “region of indistinct symmetry” at 0.2≤x≤1.0, which forestalls the transition to the non-polar cubic phase at temperature increase;-formation of two morphotropic regions: contracting (rhombic–rhombohedral) and expanding (rhombohedral–tetragonal) at temperature increase;-richness of single-symmetry phase diagram fragments by regions of coexistence of phase states.
The homogeneity regions of the real solid solutions contain phase-boundary lines of a new type evidencing of intraphase transitions prevailing in the rhombohedral phase, which show up in the presence of two and more different cell values (preserving the global crystal lattice symmetry).