Effects of CaAl2O4 on the electrical properties and temperature stability of (Na0.53K0.404Li0.066)Nb0.92Sb0.08O3 ceramics

Lead-free (1 − x)(Na0.53K0.404Li0.066)Nb0.92Sb0.08O3 + xCaAl2O4 (NKLNS–xCA) ceramics were prepared by the conventional mixed oxide method. The effects of the addition of CaAl2O4 on the phase transitions and electrical properties of the KNN-based ceramics were studied and the temperature stability of their piezoelectric and electromechanical properties was also discussed. It is found that 1.5 mol% CaAl2O4 doped NKLNS ceramic exhibits stable piezoelectric and electromechanical properties in −40 to 60 °C due to the extended polymorphic phase transition region induced by the B-site composition fluctuation. The piezoelectric constant d33, dielectric loss tanδ, and electromechanical coupling factor kp of the NKLNS–0.0150CA ceramic are found to be 254 pC/N, 3.5%, and 45%, respectively, demonstrating that the NKLNS–0.0150CA ceramic is a very promising lead-free piezoelectric material for practical applications.

► NKLNS–CA lead-free piezoelectric ceramics are synthesized by normal sintering.
► High piezoelectric properties are obtained.
► The NKLNS–CA ceramic shows very stable temperature behavior.