Relative shrinkage and activation energy of (1 − x)(Na,K)NbO3–x(Bi,Na)TiO3 depending on sintering temperature

• Activation energy for sintering process was simulated in NKN–BNT ceramics.
• The combined components of Bi and Ti lead to acceleration of sintering in NKN–BNT.
• The NKN–BNT ceramics have mixed tetragonal–orthorhombic structures with εr of 1139.

Even though (Na0.5K0.5)NbO3 (NKN) and (Bi0.5Na0.5)TiO3 (BNT) piezoelectric materials are both representative of the lead-free piezoelectric ceramics, stoichiometric preparation and sintering temperature are especially important for the (Na0.5K0.5)NbO3-based ceramics owing to sensitivity of the (Na0.5K0.5)NbO3 (NKN) to non-stoichiometry and a low reproducibility of the (Bi0.5Na0.5)TiO3 (BNT). In this work, (1 − x)(Na0.5K0.5)NbO3–x(Bi0.5Na0.5)TiO3 ceramics were prepared by varying the sintering temperature in order to improve its characteristics by complementing each other. The effects of the sintering temperature on the microstructure, and dielectric property were systematically investigated. In addition, the relative shrinkage and the activation energy of the (1 − x)(Na0.5K0.5)NbO3–x(Bi0.5Na0.5)TiO3 ceramics were analyzed at various temperatures ranging from 1080 to 1160 °C. The optimized sintering temperatures are expected to improve the dielectric and piezoelectric properties of (1 − x)(Na0.5K0.5)NbO3–x(Bi0.5Na0.5)TiO3 ceramics.

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