The influence of acceptor doping, stoichiometry and processing on the mechanical properties and microstructure of PZT ceramics

Šafář, Martin (2019). The influence of acceptor doping, stoichiometry and processing on the mechanical properties and microstructure of PZT ceramics. University of Birmingham. Ph.D.

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Abstract

Lead zirconium titanate (PZT) is the most widely used ferroelectric ceramic material on the market. The majority of published research revolves around its piezoelectric and dielectric properties. This thesis is focused on the complex dependencies between the material’s composition (Sr^{2+}, Fe^{3+} doping and Zr/Ti ratio), microstructure, structure, physical, functional and mechanical properties. The goal was to identify the most important strength-controlling factors to create stronger and more reliable PZT products and reduce their manufacturing waste.

PZT specimens were prepared from metal oxides using an optimised conventional powder processing route and industrial processing parameters. Fracture strength was tested under equibiaxial flexural stress using a custom-designed ring-on-ring fixture and the results were evaluated using a 2-parameter Weibull distribution. Large pores and machining-induced damage were identified as the weakest flaws. The pore size distribution was affected by all studied factors. The most notable increase in strength was caused by the acceptor doping, which was linked to the changes in grain boundary strength; and by an increase in the sintering temperature (for pure PZT). The strength of the acceptor-doped PZT showed no significant change with Zr/Ti ratio or sintering temperature, unlike the undoped PZT.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):