Effect of powder processing conditions on the electromechanical properties of lithium doped potassium sodium niobate

Abstract

Lithium doped potassium sodium niobate ceramics with (K0.50-x/2Na0.50-x/2Lix)NbO3 composition where x=0.04 and 0.07 were fabricated by solid state calcination and pressureless sintering methods. However, two different powder processing and calcination routes were used in this study and their effect on the structural and electrical properties were investigated and discussed. The routes were namely loose calcination and compact calcination. A general trend of decreasing grain size was observed in the sintered ceramics prepared from these powders. The most drastic effect was observed on the electromechanical properties of the samples, where the maximum strain of 7% lithium modified sample under an E-field of 50 kV/cm was increased from 0.09% to 0.12% by changing processing route. Furthermore, hysteretic behavior of the strain was found to decrease. This tendency was also valid for ferroelectric hysteresis property, with remnant polarization (2P(r)) increasing from 23 mu C/cm(2) to 46 mu C/cm(2). The improvements observed in the electrical properties were discussed on the basis of chemical homogeneity and uniform ionic distribution. (C) 2016 SECV. Published by Elsevier Espana,