An Approach to Improve the Piezoelectric Property of (Bi 0.5 Na 0.5 )TiO 3 –(Bi 0.5 K 0.5 )TiO 3 –BaTiO 3 Lead‐Free Ceramics

Lead‐free piezoelectric ceramics of an a (Bi 0.5 Na 0.5 )TiO 3 – b (Bi 0.5 K 0.5 )TiO 3 – c BaTiO 3 (BNBK) ternary system close to the composition of MPB have been widely investigated in recent decades. In this research, the MPB Linear Combination Rule (LCR) is introduced to explore the ternary system of lead‐free piezoelectric ceramics for the first time, and the best properties of d 33 =220 pC/N, k p =0.31, k t =0.476, T d =157°C, and ɛ r =1648 are obtained for a composition with a / b / c =85.25/10.995/3.755. It is suggested that BNBK with the composition (85.25/10.995/3.755) is a candidate material for lead‐free applications. Moreover, the LCR of MPB is an effective method, applicable to lead‐free ceramics to search for an optimal composition with excellent properties.