Synthesis and characterization of lead free ferroelectric materials
New concepts must be developed to achieve densification or nanostructuration in order to optimize the properties of the replacement materials and obtain compounds with similar performance as previous lead based components.
To achieve this, researchers in the OXYDES team use solid state, sol-gel and Pecchini syntheses, sintering under atmosphere or by SPS (Spark Plasma Sintering) to produce new materials. Special attention is payed on the characteristics and different qualities of their crystallographic structure as well as their micro-structural architecture, in order to link these parameters with the electro-active properties of the different material shaping and order. These researches must allow the identification and the selection of candidates with promising performances, available for potential applications. Necessarily, the existing characterization methods have to be continuously adapted to the constraints induced by the newly synthesized materials, in close collaboration with the other teams of GREMAN.
Tools and methods
Development of sintering methods
Spark plasma sintering chamber during a run and relative densities after sintering with Ta substitution in (K,Na)(Nb,Tax)O3 piezoelectric ceramics.
Shaping of ceramics, films and crystals
Grain size monitoring in KNN ceramics up to millimeter size single crystal (obtained by zone melting) enables to investigate the grain size effects on the piezoelectric properties.
Structure and micro-structure characterizations
SEM , PFM, XRD are parts of a complete set of characterizationsCareful and multiscale characterizations of the structure and microstructure evolution with compositions, synthesis and shaping methods are keys for the complete comprehension of the links between material and properties.
Materials
Powder diffractogram pure (K,Na)NbO3 after synthesis.
Transducers including different KNN ceramics and their measured echos in water.