Effects of Al2O3 on the ferroelectric properties of sodium potassium lithium niobate lead-free piezoceramics

Aluminum oxide (Al2O3) has been known as a promising additive to modify the piezoelectric properties of lead-based piezoceramics. However there are few reports regarding Al2O3 added lead-free piezoceramics. In this study, sodium potassium lithium niobate ((Na0.5K0.5)0.925Li0.075NbO3, NKLN) lead-free piezoelectric ceramics have been prepared and their crystal structures, microstructures and dielectric properties have been also investigated with different Al2O3 amounts and sintering temperatures. With increasing Al2O3 content up to 0.5 wt%, the density and grain size increased, accompanying with the increased dielectric and piezoelectric properties. These results could be explained in terms of sinterability such as density and grain size.