Glass formation and crystalline phases in the ternary systems CaO-Bi 2O3-B2O3and SrO-Bi2O 3-B2O3

Large glass forming areas in the ternary systems CaO-Bi2O 3-B2O3and SrO-Bi2O 3-B2O3have been revealed by supercooling of melts. Transparent glass samples have been obtained in a narrow bismuth-rich area of composition in the SrO-Bi2O3system. Four pseudo-binary eutectic and four peritectic compositions have been revealed in the melting diagrams of the pseudo-binary systems Bi2O 3-CaB2O4, BiBO3-CaB 2O4, Bi2O3-SrB2O 4, BiBO3-SrB2O4. The existence of ternary compounds CaBi2B2O7and CaBi 2B4O10in the CaO-Bi2O 3-B2O3system, and SrBi2B 2O7and SrBi2B4O10in the SrO-Bi2O3-B2O3system has been confirmed. These compounds have good glass forming ability and are in the area of stable glasses. The melting behaviour of ternary compounds CaBi 2B2O7, CaBi2B4O 10, SrBi2B2O7, and SrBi 2B4O10has been studied. They melt incongruently at 770,730,755 and 790°C, respectively.