CRYSTALLIZATION AND SUPERCONDUCTIVITY IN HG DOPED BI1.7PB0.3HGXSR2CA2CU3OY GLASS-CERAMICS

Hg doped superconducting glass-ceramics of compositions Bi1.7Pb0.3HgxS r2Ca2Cu3Oy (0 less than or equal to x less than or equal to 1.0) were prepared by melt-quenching, The effects of Hg addition on the glass-fo rming ability under normal furnace-cooling conditions and crystallizat ion to glass-ceramics were examined using differential thermal analysi s (DTA) and X-ray diffraction. Thermogravimetry results (TGA) show tha t similar to 2 wt.% of oxygen was absorbed at 830 degrees C during the formation of the crystallized superconducting phases from the reheate d glasses, The microstructure and superconducting properties of the Hg doped glass-ceramics were correlated and an optimal heat-treatment co ndition at 843 degrees C for 60 to 80 h was found to give the most des irable microstructure.