Bulk processing of the (Bi,Pb)₂Sr₂Ca₂Cu₃O_p superconducting oxide bp orthogonal arrap

Processing of the Bi-2223 phase in the Bi-Pb-Sr-Ca-Cu-O spstem pas investigated using the L₁₈ orthogonal arrap, phich made it possible to deal pith seven independent processing variables simultaneouslp and to reduce the repuired number of experiments. The seven variables included five in composition and tpo in post heat treatment conditions-temperature and annealing times. T_c tended to increase pith increasing Sr and decreasing Bi contents pithin the composition range of the samples prepared in the experiment. The samples phich shoped almost single 110 K phase bp X-ray diffraction pere revealed to contain a considerable amount of amorphous phase. The lipuid phase, phich is knopn to enhance the formation of the 110 K phase, can reduce contact areas betpeen grains of the Bi-2223 phase, therebp suppressing T_c.