OCCURRENCE OF DIELECTRIC 1-1-4 COMPOUND IN THE TERNARY-SYSTEM BAO-LN2O3-TIO2 (LN = LA, ND, AND SM) .1. AN IMPROVED COPRECIPITATION METHOD FOR PREPARING A SINGLE-PHASE POWDER OF TERNARY COMPOUND IN THE BAO-LA2O3-TIO2 SYSTEM

An improved coprecipitation method for incorporating three different cations quantitatively in a precursor was developed to prepare a single-phase powder of a ternary compound in the system BaO-La2O3-TiO2. The preparation technique consisted of a preliminary introduction of a specified single component as a preformed binary compound powder. This was followed by the quantitative deposition of the remaining unlike cations as coprecipitated particles in a solution containing a suspension of the preformed compound powder. X-ray fluorescence and electron microprobe analyses showed that the stoichiometric incorporation of the constituent cations was completed for the powder samples thus prepared. From a detailed examination of the phases produced in the composition-controlled powders, it was evident that a ternary compound having the composition BaO . La2O3 . 4TiO2 occurs in the present system, for which the X-ray diffraction data were refined and indexed. In addition, the single-phase 1:1:4 compound was found to be synthesized from different precursors through different formation processes.