Piezoelectric properties of the Pb(Sc1/2Nb1/2)O3 based ceramics

Piezoelectric properties and crystal structure of the Pb(Sc1/2Nb1/2)O-3 based ceramics are described. They are the ternary systems such as xPb(Sc1/2Nb1/2)O-3-yPb(Mg1/3Nb2/3)O-3-zPbTiO(3)(PSMNT/xyz) and xPb(Sc1/2Nb1/2)O-3-yPb(Zn1/3Nb2/3)O-3-zPbTiO(3) (PSZNT/xyz). For the PSMNT ceramics, the morphotropic phase boundary (MPB) was investigated. The MPB follows an almost linear line region between the PSMNT 58/00/42 and PSMNT 00/68/32 MPB compositions of the binary systems. The maximum piezoelectric constant, d(33)=680 pC/N, were found at PSMNT 29/33/38, where epsilon(33)/epsilon(0)=3,800, and electromechanical coupling factors, (k(p)=70%, k(31)=43%, and k(33)=76%) and T-c=207 degrees C were obtained. In the case of PSZNT ceramics, the perovskite phase exists in the composition rang of y<50. Addition of excess PbO to this system is effective for obtaining the perovskite structure. Piezoelectric properties of this system is lower compared with those of PSMNT ceramics.