Enhanced piezoelectricity over a wide sintering temperature (400–1050 °C) range in potassium sodium niobate-based ceramics by two step sintering

Abstract

Here, we report enhanced piezoelectricity over a very wide sintering temperature range (400–1050 °C) in 0.96(K_0.4Na_0.6)(Nb_0.96Sb_0.04)O₃–0.04Bi_0.5K_0.5Zr_0.9Sn_0.1O₃ lead-free ceramics prepared by two step sintering. All ceramics fall into the R–T phase boundary at room temperature, and a dense microstructure without serious loss of alkali elements was found in the samples. The enhanced dielectric, ferroelectric, and piezoelectric properties were attained by two step sintering over a wide sintering temperature range of 400–1050 °C. Most interestingly, the enhanced d₃₃ values of 350–400 pC N⁻¹ can be achieved over a wide temperature range of 400–1050 °C, and the temperature gap range of 650 °C is much wider with respect to previous studies by two step sintering. Besides, an enhanced unipolar strain of ∼0.26% (d^*₃₃ ∼ 736 pm V⁻¹) can also be attained in the ceramics.