Effect of Co3+ on Structure and Electrical Properties of Na0.5Bi2.5Nb2O9 Ceramics

Na0.5Bi2.5Nb2-xCoxO9 (NBNC-x, x = 0.00, 0.02, 0.05, 0.07, 0.09) bismuth layered piezoelectric ceramics were synthesized by the traditional solid-state method. The microstructure, piezoelectric, dielectric and ferroelectric properties of Co3+ doped NBNC-x ceramics were systematically investigated. The XRD results showed all ceramics possess bismuth layered structure. The Curie temperature (Tc) gradually enhanced from 778 to 793 °C with the addition of Co3+ content. Moreover, the Co3+ doping significantly enhance piezoactivity (d33) and ferroelectricity (Pr), and reduce dielectric loss (tan δ). The Na0.5Bi2.5Nb1.93Co0.07O9 ceramic had optimum combinations of electrical properties (e.g., d33 ~ 20.1 pC/N, Pr ~ 4.22 μC cm−2, tan δ ~ 0.31%, Qm ~ 3405). These results indicate that the Co3+ doped Na0.5Bi2.5Nb2O9 ceramics has potential application in the high-temperature field.