Preferentially oriented crystallites of Bi2CaSr2Cu2Ox ceramics formed during phase transformation

In this paper Bi2CaSr2Ox ceramics derived through glass-ceramics technique is studied under various heat treatment conditions. X-ray diffraction and SEM results indicate that the preferentially oriented crystallites of Bi2CaSr2Cu2Ox are consequences of crystalline-crystalline phase transformation rather than simple surface nucleation and growth directionally in the glass matrix. During the course of heat treatment, oxygen content in the atmosphere controls the growth rate of oriented crystallites toward the inner body of the glass-ceramic bulk. This opens up an entire new route in controlling the microstructure of the resulting superconducting ceramics. This technique is also generally applicable to derivation of 110 degrees K phase with preferred orientation