NEW TRICKS IN THE RAPID QUENCH ROUTE TO HIGH T(C) MATERIALS

High T(c) materials containing Bi form glasses when quenched from thei r melts. These materials pass through a number of intermediate phases when furnace heated, causing chemical segregation along the way; exten ded annealing is then required to achieve a chemically uniform product . Chemical uniformity is preserved from the glass directly to a high T (c) phase by placing the glass suddenly into a furnace at a temperatur e in which the final product is stable. In addition, it was found poss ible to hot press the glass flakes into a compact at a sufficiently lo w temperature without chemical segregation so that a sudden heating st ep will achieve the same result in bulk material.