PROCESS FOR PRODUCING HIGHLY CRYSTALLINE AND HOMOGENEOUS SUB-MICRON DOPED AND UNDOPED PIEZOELECTRIC CERAMIC POWDERS WITH CONTROLLED STOICHIOMETRY AND PARTICLE SIZE

摘要

PROCESS FOR PRODUCING HIGHLY CRYSTALLINE AND HOMOGENOUS SUB-MICRON DOPED AND UNDOPED PIEZOELECTRIC CERAMIC POWDERS WITH CONTROLLED STOICHOMETRY AND PARTICLE SIZE This invention provides a single crystal, solid solution, chemically homogenous powder of a lead zirconate titanate perovskite compound having useful electrical properties and the general formula Pb(Zr1-xTix)O3, wherein x has a value between 0.44 and 0.56. The powder may also contain other secondary ingredients, such as dopants and solid solution substitutions, up to 13 mole % that alter electrical properties. The powder may have a sintering temperature of less than about 1100.degree.C and a controlled average particle size ranging from about 0.4 to about 1.2 microns. A process for making this powder is also provided which comprises: (a) preparing a first acidic solution containing zirconium and titanium ions, and optionally other ions; (b) preparing a second basic solution containing a sufficient concentration of hydroxide to provide a pre-determined pH when mixed with the first solution; (c) adding the first acidic solution to the second basic solution to precipitate a substantially pure mixture of hydroxides; (d) washing the precipitate and adding a lead compound; (e) preparing an aqueous slurry of the washed precipitate and adding lead ions, and optionally other ions; (f) hydrothermally treating the slurry at an elevated temperature and pressure for a time sufficient to form the powder; and (g) drying the powder.