Effects of sintering temperature and poling process on Li _0.058(Na_0.51K_0.49)_0.942NbO ₃ piezoceramics

The influence of sintering temperature and poling processing on the room temperature phase structure and piezoelectric properties of Li _0.058(Na_0.51K_0.49)_0.942NbO ₃ ceramics were systematically investigated. An approach was proposed to roughly determine the ratio of tetragonal and orthorhombic phase in the as-sintered samples. The result of temperature dependence of the dielectric constant proves this method feasible. The best piezoelectric properties of d₃₃ = 255 pC/N was obtained in specimens sintered at 1040 C. The dense microstructure and high percentage of 90 domains reorientation during poling processing could explain the best performance of samples for 1040 C. The loose microstructure and low density for the samples of 980 and 1080 C are responsible for the worse piezoelectric properties comparing with that of sample for 1040 C. Meanwhile, the segregation also plays an important role in the deteriorate properties for the sample sintered at 1080 C.