Abstract
As a rule crystallization of amorphous Bi2Sr2CaCu2Oy leads to the 24A phase followed by the formation of the 30A phase above 800°C. The nominal composition of the 24A phase is Bi2Sr2CuOy and hence the crystallization into the 24A phase causes the problem of the discrepancy of composition. In order to solve the problem, crystallization process of fast-quenched Bi2Sr2CaCu2Oy has been examined by using the X-ray diffraction and SEM-EDX. It has been found that the crystallization of amorphous Bi2Sr2CaCu2Oy into the 24A phase was accompanied with the phase separation into the 244 phase and a Cu-rich region so as to adjust the compositions. In the next step of crystallization, the separated regions reacted together above 800°C into the 30A phase.
