文摘
The piezoelectricity of (K,Na)NbO3 ceramics strongly depends on the phase boundary types as well as the doped compositions. Here, we systematically studied the relationships between the compositions and phase boundary types in (K,Na) (Nb,Sb)O3鈥揃i0.5Na0.5AO3 (KNNS-BNA, A = Hf, Zr, Ti, Sn) ceramics; then their piezoelectricity can be readily modified. Their phase boundary types are determined by the doped elements. A rhombohedral-tetragonal (R鈥揟) phase boundary can be driven in the compositions range of 0.035 鈮?BNH 鈮?0.040 and 0.035 鈮?BNZ 鈮?0.045; an orthorhombic-tetragonal (O鈥揟) phase boundary is formed in the composition range of 0.005 鈮?BNT 鈮?0.02; and a pure O phase can be only observed regardless of BNS content (鈮?.01). In addition, the phase boundary types strongly affect their corresponding piezoelectricities. A larger d33 (鈭?40鈥?50 pC/N) and a higher d33* (鈭?42鈥?34 pm/V) can be attained in KNNS-BNA (A = Zr and Hf) ceramics due to the involvement of R鈥揟 phase boundary, and unfortunately KNNS-BNA (A = Sn and Ti) ceramics possess a relatively poor piezoelectricity (d33 鈮?200 and d33* < 600 pm/V) due to the involvement of other phase structures (O鈥揟 or O). In addition, the underlying physical mechanisms for the relationships between piezoelectricity and phase boundary types were also discussed. We believe that comprehensive research can design more excellent ceramic systems concerning potassium鈥搒odium niobate.