Synthesis of bismuth superconducting cuprates preliminary annealing of intermediate compounds

Bi(Pb)-containing HTSC-ceramics was prepared by the method of preliminary annealed intermediate compounds following two schemes: Bi(Pb)-Ca-O+Sr-Ca-Cu-O(1) and Bi(Pb)-Ca-Cu-O+Sr-Ca-Cu-O(2) as well as through direct mixing of oxides-carbonates, nitrates, acetates or through sedimentation of oxalates in an organic medium. Mixing technique produces a great effect on ceramics properties. In all cases, utilization of intermediate compounds albows to increase the rate of homolog 2223 production and to obtain samples with higher Tc(zero) as compared to direct mixing of agents. Samples produced by the scheme (2) had better properties. Possible mechanisms of interaction are discussed