Thermo-gravimetric and XRD analysis of KNN-based lead-free ceramics.

Environment protection and Human health concern is the driving force to eliminate the lead from commercial piezoelectric materials. Among lead-free ferroelectric ceramics, Potassium-sodium niobate (KxNa1-x) NbO3 (KNN) based ceramics have gain much attention as one of the effective alternatives for replacing lead-based ones. In the present study, we have synthesized 0.96(K0.48Na0.52)1-3xNdxNb0.96Sb0.04O3-0.04(Bi0.5K0.5) (Zr0.9Sn0.1) O3 (abb. as KNNNxS-BKZS) [x=0, 0.002 and 0.004] by a conventional solid-state reaction method. Thermal behaviour of mixed powders has been studied through TGA-DSC analysis to estimate the calcination temperature. TGA curve shows that, above 770°C, the decomposition of carbonates has completed and no significant weight loss has been observed after this temperature. A perovskite structure has been revealed in calcined as well as sintered ceramics through XRD analysis. The maximum crystallite size of calcined powders found to be ∼14.00 nm for x=0.002. Further, the crystallite size of the calcined powder for x=0 composition has been found to increase from ∼12.47 nm to ∼17.37 nm after sintering. [ABSTRACT FROM AUTHOR]