Textured processing, reactive templated grain growth, and electrical property relationships for sodium bismuth titanate PI015

Abstract

The investigation of lead-free piezoelectric ceramic compositions has recently gained an increased level of interest due to the efforts to reduce lead based components. The most widely used piezoelectric/ferroelectric ceramic material today, including specialized ceramics for military applications (ex. sonar), consists of PbTiO3-PbZrO3 (i.e. PZT-system). It has become imperative to integrate a processing strategy with a lead-free ferroelectric material capable of competing with or surpassing the properties of lead-based compositions. This work examines the development of optimal processing parameters through texturing and reactive templated grain growth to selectively engineer a polycrystalline ceramic microstructure. It presents how these parameters can affect the electro-mechanical properties for a sodium bismuth titanate based composition. The final properties for all ceramic materials are highly influenced by the processing steps and forming techniques used to construct the bulk ceramic component. Texturally modified ceramic compositions have recently exhibited enhanced properties that, depending on the system, match and even surpass those of an optimum modified lead-based composition. In this work we report on the development and use of a texture induced forming process combined with reactive templated grain growth to produce grain-oriented polycrystalline bulk ceramics. Thermal analysis, x-ray diffraction characterization, microstructure stereology and the dielectric and electromechanical performance will be presented. A processing space has been characterized and mapped in order to drive towards achieving maximized electrical performance for this lead-free system.