PZT ceramics from hydrothermally synthesized powders

Abstract

PZT (PbTi/sub 1-x/Zr/sub x/O/sub 3/, x=0.52 to 0.64) powders were hydrothermally produced at 200/spl deg/C for 24 hrs, from a solution containing Ti(OH)4/spl middot/xH/sub 2/O, ZrOCl/sub 2/, Pb(CH/sub 3/COO)/sub z/, and NaOH. PZT (x=0.52) powder was also produced by the solid-state sintering method. The powders from both the hydrothermal method and the solid-state reaction method were pressed and subsequently sintered at 1250/spl deg/C for 2 hrs. The characteristic difference of the ceramics produced from both powders were compared with each other. The hydrothermal PZT powders are chemically homogeneous, and around 0.2 /spl mu/m in particle size (numerical average). The solid state reacted powder is a mixture of tetragonal PbTiO/sub 3/, rhombohedral PbZrO/sub 3/, unreacted TiO/sub z/, and unreacted PbO. The PZT ceramics from hydrothermal powders become softer, i.e., lower Ec and higher Pr, as more Zr/sub x/ is added in PZT (higher x value). The K, Q, and Kp values reach maximum when x=0.54. The Q value monotonously increases with the x value and the Kp value likely increase with the grain size of the ceramics. The ceramics from the hydrothermal method have higher density, grain size, dielectric constant, Kp, and lower D and Qm. The hydrothermal powders are much more sinterable than powders produced by the solid-state reaction method.