Abstract
To enhance the formation of Bi,Sr,Ca,Cu,O,(Bi-2223) single phase in a shorter reaction time, the intermediate compounds such as Bi,Sr,CuO,(Bi-2201). BizSr,CaCuz08(Bi-2212) and (Ca, Sr,, ,9)CuOz in the Bi-Sr-Ca-Cu-0 system were used as the precursors. The formation of Bi-2223 was enhanced in the mixture of Bi-2201 and (Ca, ,,Sr, 119)C~eOsZpe,c ially from the mixture with (Ca, 9I Sr, ,,)CuO,-rich composition compared to Bi, iPb, 4Sr2Ca,Cu3010-cxo mposition. The formation of Bi- 2223 essentially completed within 60h at 860$^{\circ}$C and 870$^{\circ}$C. However, a small amount of the remnant Bi-2212 phase did not disappear even after a prolonged reaction at 870'C. The merit of the proposed synthetic method using the intermediate precusors can be summarized as a shorter reaction time for the formation of Bi-2223 phase, in addition to a smaller amount of second phases compared to the conventional solid-state reaction method.
Bi-계 고온초전도체인 Bi2Sr2Ca2Cu3O10(Bi-2223)단일상을 반응시간을 줄이면서 합성하기 위하여 Bi-Sr-Ca-Cu-O계 내에 존재하는 Bi2Sr2Ca2Cu3O10(Bi-22o1), Bi2Sr2Ca2Cu3O10(Bi-2212), (Ca0.91Sr0.09)-CuO2의 혼합물, 특히 정확한 Bi1.7Pb0.4Sr2Ca2Cu3O10+x의 조성대신 (Ca0.91Sr0.09)CuO2가 많이 첨가된 조성의 혼합물에서 Bi-2223가 가장 쉽게 형성되었다. Bi-2223상은 86$0^{\circ}C$와 87$0^{\circ}C$에서 60시간 이내에 형성되었다. 소량의 Bi-2212상은 장시간의 반응후에도 여전히 존재하였다. 중간화합물을 이용한 합성방법이 통상의 소결방법에 비해 반응시간내에 소량의 불순물상들을 가진 Bi-2223상을 형성시킬 수 있다.
