Flux Pinning Additions to Increase Jc Performance in BSCCO-2212 Round Wire for Very High Field Magnets

With the drive towards higher field dipole magnets ¿ the engineering goal for the near term (7-10 years) is at least 15 T ¿ the material requirements for superconductors are becoming stringent. While the processing and application of existing metal-based materials have advanced to a significantly higher level than those of their ceramic counterparts, which can sustain high critical temperature (the highest temperature at which the material can maintain superconductivity), the ceramics have the advantage of an extremely high-critical field values. For this reason, the ceramic superconductor, bismuth strontium calcium copper oxide (BSCCO-2212) in the form of a multifilamentary Ag alloy composite, is beginning to attract interest for future extremely high-field magnets or magnet-insert coils for 4.2K operation. This project will develop a commercially viable, BSCCO-2212/Ag composite multifilamentary round wire with a Je value equal to or exceeding 600 A/mm2 at 12T and 4.2K. In Phase I, several additive materials will be investigated and selected for further work, based on the microstructure of the BSCCO-2212 layer that is formed by using spin coating and melt processing. Additives that provide promising microstructures in spin coated samples will be evaluated for superconducting properties at a 4.2K self-field in dip-coated tape form. After an evaluation at 4.2K and a microstructural evaluation, promising candidates will be selected for scale-up in Phase II to 1 km length round wires. Commercial Applications and other Benefits as described by the awardee: The initial commercial application of BSCCO-2212/Ag composite wire should be in high field magnets for high energy physics experimentation. Other potential applications would exist anywhere high field magnets are required, such as medical MRI.