PREPARATION OF NEEDLE-LIKE TIZRO4 AND PZT POWDERS

Needle-like TiZrO4 powder was prepared by reacting TiO2 and ZrO2 in the presence of molten chloride (NaCl or KCl) or sulphate (Na2SO4 or Li2SO4). Either a single-phase TiZrO4 or a three-phase mixture (TiZrO4, ZrO2 and amorphous TiO2) was obtained from the chloride or sulphate system. Particle morphology was dependent on heating temperature and duration as well as salt species. Needle-like PZT powder was obtained by reacting needle-like TiZrO4 powder with PbO above 750-degrees-C. The PZT powder obtained at 750-degrees-C was composed of both tetragonal and rhombohedral phases, indicating a wide compositional variation. An increase in heating temperature reduced the degree of compositional variation, but enhanced the deformation of needle-like particles.