Dielectric properties of PLZT prepared by three sol-gel methods

Lead lanthanum zirconate titanate (PLZT) powders were prepared by three different sol-gel methods. In one process, the precursor materials used were lead hydroxide, lanthanum nitrate hexahydrate, zirconium tetra-n-butoxide, and titanium tetraisopropoxide along with 2-methoxyethanol as a solvent. An amount of distilled water equivalent to the total molar concentration of Pb, Ti, and Zr was added to the above solution. In a second process, the precursor materials used were lead acetate, lanthanum nitrate hexahydrate, zirconium tetra-n-butoxide, and titanium tetraisopropoxide along with 2-methoxyethanol as a solvent. An amount of distilled water equivalent to the total molar concentration of Pb, Ti, and Zr was added to the above solution. In a third process, the precursor materials used were lead acetate, lanthanum nitrate hexahydrate, zirconyl nitrate, and titanium tetra-n-butoxide. Distilled water and acetic acid were used as solvents. Triethyleneglycol or diethanolamine was used in each of the above processes as a chemical additive to modify the hydrolysis and condensation of the solution. Thermal gravimetric-differential thermal analysis was used to study the weight changes of the dried gels as a function of annealing temperature. Dried samples were heated for 1 h in the range of 673 to 1073 K in air atmosphere. The crystalline phases of calcined PLZT powders were identified by X-ray diffraction analysis. The calcined powder was pressed by CIP at 100 MPa. The samples were sintered at 1173 K, 1273 K, and 1323 K and their relative dielectric constants were measured.