Yurchenko I. Intensification of synthesis and properties examination of high-temperature superconducting ceramics Bi(Pb)-Sr-Ca-Cu-O

The dissertation is devoted to a problem of acceleration of synthesis of bismuth high-temperature superconducting ceramics with dominance of Bi2Sr2Ca2Cu3O10+х (2223) phase and structure ensuring a narrow interval of superconducting transition (from magnetic susceptibility) at temperature higher 100 K. Series of technology factors influence properties of bismuth ceramics is investigated, that has allowed to reduce from 70-250 to 25 h the time of high-temperature annealing for obtaining material with indicated performances. The phase formation processes at high-temperature stages of technology of bismuth ceramics manufacture - at decomposition of saline product of spray frozen, freeze drying synthesis and during a sintering, are studied. The conditions of 2223 phase additive influence synthesis of this phase and structure of ceramics are spotted. The conclusions concerning definition of phase composition and structure of bismuth superconducting ceramics from temperature dependence of magnetic susceptibil ity are made. Technological cycle of bismuth ceramics manufacture considered with points of view of processes occurring in material; the scheme of structural and phase transformations at sintering is offered.