Improvement of Critical Current Density in the Bronze-Processed Nb3Sn Superconductor
The superconductors with bronze matrix of Cu-15wt%Sn-0.3wt%Ti were fabricated on a commercial scale. The number of filaments and Cu to non Cu ratio of the conductors were 25099 and 0.3, respectively. A non Cu Jc of 980 A/mm2 at 12 T, 4.2 K was obtained for a conductor with a round cross section in diameter of 0.7 mm. A rectangular shaped conductor, i. e. 1.75 mm × 3.50 mm, showed a non Cu Je of 133 A/mm2 at 21 T and 1.8 K, corresponding to a critical current of 620 A. The dependence of non Cu Jc on heat treatment conditions is also reported. These characteristics are considered with results from microscopic observations and relations with upper critical fields based on the pinning properties.
KeywordsCritical Current Density Field Region Heat Treatment Condition High Field Region Magnetic Field Region
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