Scale-dependent properties in lead free piezoelectric ceramics” (ProLEAF)
Project code: PN-III-P1-1.1-TE-2016-1951
Project number: 22/2.05.2018
Funded by the Executive Unit for Financing High Education, Research, Development and Innovation, CNCS – UEFISCDI
Piezoelectric materials are used in many applications due to their ability to generate electric charge by application of mechanical pressure, or strain under the application of an electric field. For more than half a century, lead zirconate titanate family has been the prototype among the piezoelectric materials due to its large piezoelectric coefficient. However, the environment pollution caused by highly toxic lead has induced an urgent need in developing various lead-free piezoelectric ceramics for the demands of various applications. From lead free piezoelectric materials, BZT-BCT systems at morphotropic phase boundary seems to have similar performances with Pb-based materials. Take into account that BZT-BCT is a BaTiO3- based solid solution, the question that arises is if its properties may be influenced by similar parameters as pure BaTiO3. Therefore, a major challenge is to understand the role of grain size on the functional properties of BZT-BCT systems at its morphotropic phase boundary (MPB) for searching an optimal size for maximising the piezoelectric coefficient. The aim of the present project is to use a complex modelling-experimental approach to search an optimum size and to understand the origin of scale dependent properties and mixing degree level in lead free piezoelectric ceramics with GS larger than ~1 micrometer. For this aim, single phase and composite BZT-BCT dense ceramics, with compositions near the MPB and grain size in the range above ~1micrometer, will be comparatively investigated and their properties will be described by appropriate models. A highly scientific impact will have the combination of the present models with complex multiscale models able to describe size- dependent macroscopic properties. The project will help the Romanian group to preserve its leader role in experimental-modelling approach for describing size effects phenomena in ferroelectric based materials.