SmAlO3-modified (K0.5Na0.5)0.95Li0.05Sb0.05Nb0.95O3 lead-free ceramics with a wide sintering temperature range

Abstract Lead-free ceramics (1 −  x )(K 0.5 Na 0.5 ) 0.95 Li 0.05 Sb 0.05 Nb 0.95 O 3 - x SmAlO 3 (KNLNS- x SA) were prepared by conventional sintering technique. The phase structure, dielectric and piezoelectric properties of the ceramics were investigated. All compositions show a main perovskite structure, exhibiting room-temperature symmetries of tetragonal at x  ≤ 0.0075, of pseudo-cubic at x  = 0.0100. The Curie temperature of KNLNS- x SA ceramics decreases with increasing SmAlO 3 content. Moreover, the addition of SmAlO 3 can effectively broaden the sintering temperature range of the ceramics. The KNLNS- x SA ceramic with x  = 0.0050 has an excellent electrical behavior of piezoelectric coefficient d 33  = 226 pC/N, planar mode electromechanical coupling coefficient k p  = 38%, dielectric loss tan  δ  = 3.0%, mechanical quality factor Q m  = 60, and Curie temperature T C  = 327 °C, suggesting that this material could be a promising lead-free piezoelectric candidate for piezoelectric applications.