Effect of sintering parameters on the electrical and the piezoelectric properties of double-calcined (K0.48Na0.48Li0.04) (Nb0.96Sb0.04) O3 nanopowders

The present work is an attempt towards understanding the effect of sintering parameters on the various morphological, electrical and piezoelectric properties of (K 0.48 Na 0.48 Li 0.04 ) (Nb 0.96 Sb 0.04 ) O 3 (KNLNS) ceramics. We first synthesized the powder composition from various raw materials by using a conventional solid-state reaction method followed by high-energy ball milling. The powder sample was then sintered under various sintering conditions with temperatures ranging from 1050°C to 1090°C and durations from 2 h to 3 h. The ceramic samples so obtained were then characterized for various properties. The density was found to increase significantly within a narrow temperature range, but tended to decrease when the sintering temperature slightly exceeded the optimal one. Also, by merely reducing the duration of sintering from 3 h to 2 h while keeping the temperature constant, we observed an enhancement in the density of the ceramics by about 10% ~ 20%. The room-temperature dielectric constant ( εRT ), the electromechanical coupling factor ( k p ) and the piezoelectric charge constant ( d 33 ) were found to vary with the sintering parameters. The study reveals the necessity for striking a strict balance between the sintering temperature and the sintering period in order to improve the microstructural, dielectric and piezoelectric properties of such a ceramic composition containing highly-volatile alkaline members.