SYNTHESIS AND CHARACTERISATION OF DIELECTRIC COMPOSITES PRODUCED FROM GLYCINE AND ALKALINE NIOBATE-BASED CERAMICS

Abstract

Glycine exhibits a little piezoelectric response when poled, while lead-free alkaline niobate-based ceramics show much higher responses. This research investigates the synthesis of a dielectric composite from a combination of glycine and (K0.45Na0.51Li0.04) (Nb0.85Ta0.1Sb0.04) O3 (KNNLST) ceramics. The mixed oxide ceramics synthesis method was used to produce the ceramics, while glycine powder was commercially procured. The composition range of the shaped and heat-treated composites is from no ceramics to 100 wt.% ceramics content. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), dielectric studies, and hysteresis measurements were used to characterize the samples. The obtained phases transformed from the monoclinic phase in glycine to a two-phase orthorhombic-tetragonal phase in the ceramics. The samples’ morphology revealed a dense microstructure with some cracks, large porosity, and smaller grain sizes. The dielectric properties showed increasing dielectric constant and loss values with increasing ceramics content, while the ac conductivity also increased with rising ceramics content. Improving the range of ceramics led to polarization hysteresis graphs indicating ferroelectricity in the samples. The properties of the composites show they can be used in electromechanical devices.

Keywords

• glycine
• composites
• knnlst ceramics
• amino acid
• dielectric