Improving non-sensitivity of sintering behavior in KNN-based ceramics via Fe2O3 doping

The non-sensitivity of sintering behavior in piezoceramics is critical to realize the large-scale industrial productions. However, high piezoelectricity in lead-free KNN-based ceramics can usually only be achieved in very narrow sintering temperature regions. Herein, we provide a simple method to broaden the sintering temperature range with decreased sintering temperature sensitivity by adding appropriate sintering aid Fe2O3. Compared with the narrow sintering temperature range (20-30 degrees C) of previous KNN-based ceramics, the prepared ceramics exhibit a much wider sintering temperature range (-100 degrees C). The optimal properties (d33 = 370 pC/N, d3*3 = 447 pm/V, kp = 0.47, TC = 323 degrees C) are obtained in the ceramics sintered at Ts = 1040 degrees C. Relevant impedance characterization demonstrates the origination (defect-dependent grain growth me-chanism) of enhanced electric and sintering properties. It is believed this work can provide a feasible and effective method for widening the sintering temperature and obtaining high piezoelectricity in KNN-based material system at the same time.(c) 2023 Elsevier B.V. All rights reserved.