The property improvement of lead-free Li0.058(K0.535Na0.48)0.966(Nb0.9Ta0.1) O3-based (LKNNT-based) piezoelectric ceramics with high mechanical quality factor (Qm)

摘要

In this study, LiF (Lithium Fluoride) and HfO₂(Hafnium Oxide) were selected and doped with CuO (Copper Oxide) as a sintering promoter to improve the mechanical quality of Li_0.058(K_0.480Na_0.535)_0.966(Nb_0.90Ta_0.10) O₃lead-free piezoelectric ceramics. A series of [Li_0.058(K_0.480Na_0.535)_0.966(Nb_0.90Ta_0.10) O₃-(0.2 wt% LiF + 0.1 wt% HfO₂)] + xCuO [LKNNT-(0.2L0.1H)] + x CuO(x= 0, 0.5, 0.75, 1, 2, 3, 4, 5 wt%) of lead-free piezoelectric ceramics were prepared by conventional solid state sintering. For a selected LiF content 0.2 wt% and HfO₂content 0.1 wt%, a high density and high electromechanical coupling was achieved due to the modest addition of LiF and HfO₂with the addition of 0.75 wt% CuO. Beside the mechanical quality factor Q_malso increased from 725 to 1,365. The specifications of this study including 98.82% of relative density, piezoelectric coefficient d₃₃= 360 pC / N, dielectric constant k_p= 48%, dielectric constant ε_r= 2,764, and dielectric loss tanδ = 1.1% are superior to other LKNNT-based ceramic.