Characterization of potassium-modified Li0.12Na0.88Nb0.97Sb0.03O3 lead-free piezoceramics

Abstract Potassium modified Li 0.12 Na 0.88 Nb 0.97 Sb 0.03 O 3 (LNNS) based piezoceramics were synthesized by solid state sintering methods. In this work, the substitution of voluminous K + ions induced a phase transition from orthorhombic to pseudo-tetragonal structure. This transition increased the rattling space in BO 6 octahedra, leading to an increase of Curie-temperature ( T C ). The dielectric behavior above T C was also studied and followed the well-known Curie–Weiss law. The para-ferroelectric phase transition shows the typical displacive ferroelectric behavior and belongs to the first-order phase transition. A set of material constants was characterized by using a resonance–antiresonance method in LNN-based piezoceramics. It was found that the potassium-modifications make a ‘softening’ effect on LNNS-based piezoceramics. Additionally, high piezoelectric voltage coefficient ( g 33  ∼ 50 mV m/N) was found in LNNS-based ceramics.