Pyrochlore free 0.67PMN–0.33PT ceramics prepared by particle-coating method

In present study, pyrochlore-free 0.67Pb(Mg1/3Nb2/3)O3–0.33PbTiO3 (0.67PMN–0.33PT) powders and ceramics have been successfully prepared. Using oxides as raw materials, pyrochlore-free 0.67PMN–0.33PT powders were obtained by two-step particle-coating method. The XRD and EDS results confirmed that the Mg–citric acid polymeric complex coatings effectively prevent the direct contact between PbO and Nb2O5 and thus avoid the formation of pyrochlore phase. The obtained pyrochlore-free 0.67PMN–0.33PT powders at 800 °C showed uniform and even grain size. The 0.67PMN–0.33PT ceramics sintered at 1150 °C for 2 h exhibited 99% of relative density and a piezoelectric coefficient (d33) of 576pC/N, a remnant polarization (Pr) of 28.4 μC/cm2, a planar electromechanical coupling factor (kp) of 0.55 and a mechanical quality factor (Qm) of 90.