PHASE-RELATIONSHIPS OF THE PB-SR-CA-O SYSTEM IN AIR

The subsolidus phase relationships of the PbO-SrO-CaO system in air we re investigated at 830 degrees C to 835 degrees C, Complete solid solu tion exists between Ca2PbO4 and Sr2PbO4. Compatibility between SrPbO3 and the (Ca,Sr)(2)PbO4 solid solution terminates at approximately (Ca0 .80Sr0.20)(2)PbO4. Tie-line relationships between (Ca,Sr)(2)PbO4 and P bO, SrPbO3, and the solid solutions (Ca,Sr)O and (Sr,Ca)O were also de termined. At 830 degrees C to 835 degrees C, SrO and CaO do not form a complete solid solution, Tie-lines were found to extend from the Ca-r ich solid solution (CaO to Ca0.89Sr0.11O) to nearly the entire range o f (Ca,Sr)(2)PbO4. Tie-lines were also found between (Sr,Ca)(2)PbO4 (fr om Sr2PbO4 to Sr1.95Ca0.5PbO4) and (Sr,Ca)O (from SrO to Sr0.83Ca0.17O ). No other ternary oxide phases were found in this system.