Yuancheng Teng

Effects of Li content on the phase structure and electrical properties of lead-free (Ag0.85−xLixNa0.1K0.05)NbO3 piezoelectric ceramics

Lead-free ceramics (Ag0.85−xLixNa0.1K0.05)NbO3 (ALNKN−x, x = 0−0.16) doped with 0.5 mol. % CuO were prepared by solid state reaction method under air atmosphere. The effects of Li content on the phase structure and electrical properties of the ALNKN−x ceramics were investigated. A morphotropic phase boundary (MPB) between orthorhombic and rhombohedral phases is found at x ≈ 0.08−0.14. Both the ferroelectric–ferroelectric phase transition temperature (TFE) and Curie temperature (TC) shift toward higher temperatures with increasing x. Only the phase transition peak near the TC is observed when x ≥ 0.12. The ferroelectric phase of the ALNKN−x ceramics becomes more stable with increasing x. Furthermore, the ceramics with x = 0.12 exhibit relatively good electrical properties along with a high Curie temperature (d33 = 44 pC/N, kp = 17.7%, Pr = 14.5 µC/cm2, Ec = 37.2 kV/cm, and Tc = 335 °C). The results provide helpful guidance to develop new lead-free piezoelectric materials with good temperature stability.