EFFECT OF CU2-STABILITY AND PHASE-SEPARATION IN BI2SR2CACU2OX GLASS( IONS ON THERMAL)

Bi2Sr2CaCu2Ox glass powders with high Cu2+ content were prepared by ox idizing Cu+ to Cu2+ through annealing the glass powders in oxygen at a temperature near the glass transition (430 degrees C, 0.5-72 h) witho ut causing crystallization. Both the glass transition and crystallizat ion temperatures change at around Cu2+/Sigma Cu = 0.8. In the as-quenc hed glass with Cu2+/Sigma Cu = 0.2, phase separation is observed using transmission electron microscopy, but in the annealed glass with Cu2/Sigma Cu = 1.0, a microstructure with a clear contrast is not observe d, indicating no phase separation. The phase-separation in the Bi(2)Sr (2)CaCu2O(x) glass is promoted by Cu+ ions.