Low‐Temperature Sintering of CuO‐Doped 0.94(K _0.48 Na _0.535 )NbO ₃ –0.06LiNbO ₃ Lead‐Free Piezoelectric Ceramics

Abstract

Lead‐free 0.94(K 0.48 Na 0.535 )NbO 3 –0.06LiNbO 3 – x mol%CuO ceramics were synthesized by conventional ceramics processes. The doping of CuO can decrease the sintering temperature to 890°C and effectively promote the densification of 0.94(K 0.48 Na 0.535 )NbO 3 –0.06LiNbO 3 ceramics. X‐ray diffraction result reveals that doping of CuO induces lattice distortion. Homogeneous grain growth is observed, due to the presence of liquid phase that resulted from the addition of CuO. The ceramics sintered at 890°C show fairly good properties with the planar electromechanical coupling factor k p =34.8%, piezoelectric constant d 33 =157.5 pC/N, dielectric constant ɛ 33 T /ɛ 0 =391, and mechanical quality factor Q m =173.5.