Composition design, phase transitions and electrical properties of Sr2+-substituted xPZN–0.1PNN–(0.9−x)PZT piezoelectric ceramics

The influences of PZN content and Sr2+ substitution on the structure and electrical properties of Pb(Zn1/3Nb2/3)O3–Pb(Ni1/3Nb2/3)O3–Pb(Zr0.52Ti0.48)O3 (abbreviated as PZN–PNN–PZT) piezoelectric ceramics were studied. All as-prepared PZN–PNN–PZT ceramics presented single phase of perovskite structure, while higher PZN contents favored rhombohedral symmetry and larger grain size. Meanwhile, with the increase in Sr2+ content, the phase structure changed from a mix of tetragonal and rhombohedral symmetries to a pure rhombohedral symmetry. Although the ferroelectric Curie temperature (TC) was decreased with increasing the PZN and Sr2+ contents, the piezoelectric constant (d33) exhibited the opposite trend. As a result, optimum comprehensive electrical properties were obtained in the 0.1PZN–0.1PNN–0.8PZT composition with 10 mol% Sr2+ substitution: d33~800 pC/N, kp ~0.65, ɛr~4081, TC~176 °C, Pr~30.92 µC/cm2. Thus, the 10 mol% Sr2+-substituted 0.1PZN–0.1PNN–0.8PZT ceramic is a promising candidate for high performance applications.