Rapid synthesize of Bi-2223 precursor for the fabrication of superconducting tapes using electrophoretic deposition

Abstract

A fast and economic method of synthesis of a superconducting precursor was developed. The Bi 2Sr 2CaCu 2O 8+ x superconducting phase with a T c of 80 K and a mixture of Ca 2CuO 3, Ca 2PbO 4, and CuO were synthesized separately. These two powders were then pulverized, blended, and reacted in air at 820–860°C using multi-stage heat treatment with intermediate attrition millings. The process yielded a precursor with a main phase (approximately 72%) of Bi 2− δ Pb δ Sr 2Ca 2Cu 3O 10+ x in a short total sintering time of 40 h with the elimination of the routine pelletization process in conventional ceramic processing. The optimal heating time between consecutive millings was found to be 8 h, equivalent to a Bi-2223 formation rate of 1.8% per hour of sintering, which was four times quicker than the conventional processing. The J c of the Bi-2223/Ag tapes so made by electrophoretic deposition is at the 30 000 A cm −2 level at 77 K and 0 T.