Influence of rare-earth Nd, Dy, and Ho doping on structural and electrical properties of (Na0.53K0.47)0.942Li0.058NbO3 based lead-free piezoceramics

Influence of larger rare-earth Nd and intermediate rare-earth Dy and Ho on the structure, doping behavior, dielectric, and piezoelectric properties of (Na0.53K0.47)0.942Li0.058NbO3 (KNNLN) lead-free ceramics was reported. Phase transition in KNNLN ceramics with increasing Nd, Dy, and Ho doping content occurs from the coexistence of tetragonal–orthorhombic phases to tetragonal–orthorhombic–pseudocubic phases. Both larger rare-earth Nd and intermediate rare-earth Dy and Ho ions preferentially occupy A-site and then B-site as amphoteric ions when Nd, Dy, and Ho doping content increases. Nd, Dy, and Ho doping can increase sintering density, tailor grain morphology and size, and improve piezoelectric coefficient of KNNLN ceramics. Grain size of Nd, Dy, and Ho doped KNNLN ceramics is more homogeneous and much finer than that of undoped ones. KNNLN lead-free ceramic with 2 wt% Nd doping exhibits an optimum piezoelectric coefficient (d33) ~128 pCN−1.