PHASE-EQUILIBRIA IN THE BATIO3-LA2TIO5-TIO2 SYSTEM

Subsolidus phase relations in the BaTiO3-La2TiO5-TiO2 part of the tern ary BaO-La2O3-TiO2 system at 1300 degrees C in air were determined. Th e phases were characterized by x-ray diffraction, scanning electron mi croscopy, and electron probe wavelength dispersive spectroscopic micro analysis. A combination of techniques was employed because of insensit ivity in detecting secondary phases by x-ray diffraction. The location and extent of Ba6-xLa8+2x/3Ti18O54 ternary solid solution 0.2(1) less than or equal to x less than or equal to 2.3(1) and Ba1-yLayTi1-y/4 ( V-Ti)(y/4)O-3 binary solid solution 0 less than or equal to y less tha n or equal to 0.3 at 1300 degrees C was established. Tie lines between various barium polytitanates with a sequence of Ba6-xLa8+2x/3Ti18O54 solid solution regions were determined.