Effect of addition of MnO2 on piezoelectric properties of PNW–PMS–PZT ceramics

The piezoelectric ceramics Pb(Ni1/2W1/2)O3–Pb(Mn1/3Sb2/3)O3–Pb(Ti1/2Zr1/2)O3–x wt% MnO2 (abbreviated as PNW–PMS–PZT) were prepared by traditional ceramics process. The phase structure of ceramics sintered at 1150 °C was analyzed. Results show that the pure perovskite phase is in ceramics specimens. The effect of MnO2 doping on dielectric and piezoelectric properties was investigated. When the content of MnO2 was less than 0.2 wt%, dielectric constant ɛr, piezoelectric constant d33 and mechanical quality factor Qm increased, dielectric loss tan δ decreased. When the content of MnO2 was more than 0.2 wt%, ɛr, d33 and Qm decreased, tan δ increased with increasing amount of MnO2. kp and Tc decreased all the while with the amount of MnO2 increased. The piezoelectric ceramics with 0.2 wt% MnO2 is suited for high-power piezoelectric transformer, and properties were ɛr = 2138, tan δ = 0.0058, kp = 0.613, Qm = 1275, d33 = 380 pC/N, Tc = 205 °C.