A15 multifilamentary superconductors by the infiltration process

Conference · Thu May 01 04:00:00 EDT 1980

OSTI ID:5217163

Pickus, M R; Holthuis, J T; Rosen, M

The inherent brittleness of the A15 compounds, and the requirement for a filamentary morphology, led to a heavy reliance on a powder approach for the preparation of superconducting tapes and wires. The quench-age technique, a non-powder process, was employed for the niobium-aluminum system, following the special features of the equilibrium phase diagram. The powder approach proved particularly effective for binaries, such as Nb-Sn, and for the ternaries Nb(Al,Ge) and Nb(Al,Si). Two variations of the powder process were assessed. One involved the use of precompounded powder of the desired stoichiometry but required simultaneous application of heat and pressure. The second variation was the infiltration process. This process involves the preparation of a ductile niobium matrix containing a controlled network of interconnected pores which are subsequently infiltrated with liquid metals (Sn) or low melting-point eutectics (e.g., Al-Ge, Al-Si). The composite is then subjected to a thermomechanical treatment to form a multiply connected array of A15 filaments in a niobium matrix. Multifilamentary conductors, based on Nb/sub 3/Sn, Nb/sub 3/Al, Nb/sub 3/ (Al,Ge) and Nb/sub 3/ (Al,Si), were readily obtained. Nb/sub 3/Sn conductors made by the infiltration process exhibit a critical temperature (Tc) of 18.1 K and a critical current carrying capacity (I/sub c/) of 8 x 10/sup 4/ amp.cm/sup -2/ at 12 Tesla.

• Research Organization: California Univ., Berkeley (USA). Lawrence Berkeley Lab.
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 5217163
• Report Number(s): LBL-10761; CONF-800587-5
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360101 -- Metals & Alloys-- Preparation & Fabrication
656102* -- Solid State Physics-- Superconductivity-- Acoustic
Electronic
Magnetic
Optical
& Thermal Phenomena-- (-1987)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ALLOYS
ALUMINIUM ALLOYS
BETA-W LATTICES
CRYSTAL LATTICES
CRYSTAL STRUCTURE
FABRICATION
GERMANIUM ALLOYS
METALLURGY
NIOBIUM ALLOYS
POWDER METALLURGY
SILICON ALLOYS
SUPERCONDUCTORS
TIN ALLOYS
WIRES