Composition optimization Bi2Sr2CaCu2Ox powder for high JE multifilamentary wires for high field magnets

High field magnets (>16 T) are required for next generation accelerators and upgrading existing facilities. And to enable major breakthroughs in science improving the capabilities of medical care. Multifilamentary round Bi-2212/Ag wires have demonstrated many attractive features, such as high irreversibility field (Birr > 100T), isotropic electromagnetic performance, solenoid layer winding, highest engineering critical current density, JE, at fields higher than 20T and compatibility with conventional cabling and strand insulation methods makes them one of the most promising materials to enable high field superconducting magnets. Even though there are encouraging reports on the suitability of Bi-2212/Ag multifilamentary wires, the R&D efforts for developing high field magnets is slow due to the availability and procurement cost. The ecosystem consisting of a reliable powder and wire manufacturer is needed to support future magnet development activities to realize the US next generation accelerator goals. Performance of a wire depends upon the interplay between powder characteristics, composition, wire drawing process variables and configuration, and thermal processing of the wire. Batch to batch variation in the wire performance strongly linked to the variability of powder properties is a major issue. Addressing and correcting the variability of powder batches will contribute more uniform wire performance, resulting in the cost reduction. To become successful as a powder supplier, the key challenges are to define the powder quality, to manufacture a reliable powder that will repetitively produce long length multifilamentary Bi-2212/Ag wires, and to address the powder manufacturing cost. These key issues will be addressed in this proposed Small Business Innovative Research program (SBIR). Both physical characteristics of the powder like particle/aggregate size, morphology, aggregate strength, powder flowability while compacting as well as the chemical composition needs to be optimized and controlled for reliable manufacturing of high-performance wires. The physical characteristics will determine the wire quality during thermomechanical processing from billet to multifilamentary wires and the chemical composition will be more reflected in determining the melting/recrystallization of the superconductor. Both are critical to manufacture long length wires with performance required for high magnetic field magnet. Both these parameters will be optimized in this program to minimize defects associated with thermomechanical process and to increase the high temperature heat treatment window for manufacturing long length Bi-2212/Ag multifilamentary wires for high field magnets Successful completion of this program will enable availability of a reliable powder that can be used to manufacture and reproduce the round multifilamentary Bi-2212 superconducting wires with JE >850 A/mm2 at 4.2 K & 5 T suitable for high field magnets establishing a strong domestic ecosystem that will support development of HTS high field magnets for next generation accelerators.