Effect of BBS ‐Based Frit on the Low Temperature Sintering and Electrical Properties of KNN Lead‐Free Piezoceramics

Using BaO – B 2 O 3 – SiO 2 ( BBS )‐based frit as sintering aid, the K 0.49 Na 0.51 NbO 3 ( KNN ) + x wt% BBS ( x  =   1.0, 1.5, 2.0 and 2.5) lead‐free piezoelectric ceramics were successfully fabricated by solid‐state reaction method under low‐sintering temperature of 1000°C. The effect of BBS frit doping amount on the structure and electrical properties of the ceramics was investigated. The KNN ceramics with 1.5 wt% BBS frit showed optimal properties as follows: piezoelectric constant d 33  = 108 pC /N, planar electromechanical coupling coefficient k p  = 41%, mechanical quality factor Q m  = 225, relative dielectric constant ε r  = 410, dielectric loss tan δ  = 0.57% and Curie temperature T c  = 400°C. This ceramic sample should be a good lead‐free candidate for actuators or high temperature sensors application due to its ultra‐low tan δ , relatively high Q m and T c .