THERMAL STABILIZATION OF CERAMIC SUPERCONDUCTORS FOR AEROSPACE PULSED POWER

A PH I RESEARCH PROGRAM IS PROPOSED TO DEVELOP BASELINE THERMAL DATA FOR DIELECTRIC MATERIALS IN THE RANGE 20 TO 77K FOR THERMAL-MANAGEMENT APPLICATIONS WITH THE NEW HIGH TEMPERATURE CERAMIC SUPERCONDUCTORS. THESE CERAMIC SUPERCONDUCTORS ARE BEING CONSIDERED FOR A 1 MW AIR FORCE GENERATOR. CANDIDATE DIELECTRIC MATERIALS WILL BE SELECTED FROM PREVIOUS PROGRAMS ON THE ENTHALPY STABILIZATION OF THE A15 SUPERCONDUCTORS AND FROM THE PHYSICS LITERATURE. THERMAL CONDUCTIVITY DATA WILL BE MEASURED ON THESE CANDIDATE MATERIALS, 20-77 K, AND A COMPENDIUM OF THERMAL CONDUCTIVITY DATA WILL BE COMPILED. SPECIFIC HEAT (20-77 K), THERMAL EXPANSION (20-300 K), AND DIELECTRIC PROPERTIES (20-77 K) WILL BE MEASURED ON SELECTED SAMPLES HAVING LARGE THERMAL CONDUCTIVITIES. A MINOR EFFORT WILL BE DEVOTED TO REVIEWING THE THERMAL AND ELECTRICAL PROPERTIES OF A CRYOVARISTOR FOR POSSIBLE QUENCH-PROTECTION APPLICATIONS IN THE 20-77 K TEMPERATURE RANGE. THE ANTICIPATED BENEFIT OF THE PROPOSED RESEARCH WILL BE TO ESTABLISH A DATABASE OF MEASURED THERMAL PROPERTIES, 20-77 K, ON PRACTICAL DIELECTRIC MATERIALS FOR USE IN THE THERMAL MANAGEMENT OF WIRE-LIKE STRUCTURES OF THE NEW CERAMIC SUPERCONDUCTORS (E.G., TAPES OF THE BICASRCU-OXIDE SUPERCONDUCTOR). A SECONDARY BENEFIT WILL BE THE REVIEW OF THE PROPERTIES OF A CRYOVARISTOR FOR POTENTIAL QUENCH-PROTECTION APPLICATIONS IN THE 20-77 K TEMPERATURE RANGE.