Effects of sintering temperature and poling process on Li0.058(Na0.51K0.49)0.942NbO3 piezoceramics

• The influence of sintering temperature and poling processing on the phase structure and piezoelectric properties of KNNLN ceramics were studied.
• An interesting approach was proposed to semi-quantitatively determine the amount of tetragonal phase and orthorhombic in the as-sintered samples.
• The dense microstructure and high percentage of 90° domains reorientation during poling processing could explain the best performance of samples for 1040 °C.

The influence of sintering temperature and poling processing on the room temperature phase structure and piezoelectric properties of Li0.058(Na0.51K0.49)0.942NbO3 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.

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