The Business of Science Conductor Development Project CDP
The Business of Science® Conductor Development Project (CDP) Evaluating Nexans powders for Bi-2212 Round Wire Fabrication Yibing Huang, Hanping Miao, Seung Hong, Michael Gerace and Jeff Parrell Oxford Superconducting Technology Acknowledgements U. S. DOE –High Energy Physics CDP, Lawrence Berkeley National Laboratory & ASC - Florida State University Eu. CARD 2 Meeting CERN, Dec. 12, 2013 © Oxford Instruments 2013 CONFIDENTIAL Page 1
CDP Project The Business of Science® Compare 3 powders recently produced by Nexans in Lot #82 with different particle size distributions 1. Regular ultra-fine powder (d 50 ~ 1 µm) 2. Standard granulated powder with particle size of 200 -500 µm 3. Special granulated powder with narrower particle size in 100 -200 µm © Oxford Instruments 2013 CONFIDENTIAL Page 2
Bi-2212 Wire Characterization Summary The Business of Science® Billet No. Powder feature Tap density (g/cm 3) C% (ppm) H% (ppm) Nominal composition Wire Characterization PMM 130723 -1 PMM 130723 -2 PMM 130723 -3 Regular Ultra fine 200 -500 mm 100 -200 mm d 50 ~1 mm Granulated 1. 57 1. 79 1. 94 100 60 40 76 52 44 2. 16: 1. 93: 0. 89: 2. 03 Configuration Wire size (mm) Fill factor @ 0. 8 mm wire 37 x 18 0. 80 28. 8 Barrel Ic (A, 4. 2 K & 12 T, 0. 1 m. V/cm) 130 JE (A/mm 2, 4. 2 K & 12 T) 258 Jc (A/mm 2, 4. 2 K & 12 T) 899 Wire length 407 m, in 1 piece 2 Typical JE (A/mm , 12 T) 16 per 60 cross. Hard particles sections © Oxford Instruments 2013 CONFIDENTIAL 21. 8 22. 7 136 271 1243 425 m, in 1 piece 240 -260 3 per 60 crosssections 123 244 1075 424 m, in 1 piece 12 per 60 crosssections Page 3
Wire Cross-Section Comparison The Business of Science® PMM 130723 -1 (1 mm, FF~29%) PMM 130723 -2 (200 -500 mm, FF~22%) PMM 130723 -3 (100 -200 mm, FF~23%) Ø Fill factor of the wires made of granulated powder is on purposely made lower than that of the regular ultra fine powder. Ø Wires made of the granulated powders have relatively higher homogeneity and less filament merges after drawn to final size. © Oxford Instruments 2013 CONFIDENTIAL Page 4
Regular Ultra Fine Powder Wire Cross. Section Comparison Wire from this work, FF ~29% The Business of Science® Wire from old work, FF ~26% Ø Both wires were made with ultra-fine powder (d 50 ~ 1 µm) and the same process conditions. Ø Fill factor and filament merging appear different. Ø 16 hard particles per 60 sample cross-sections in samples from this work and none from wires with standard powder made in 2005. © Oxford Instruments 2013 CONFIDENTIAL Page 5
Granulated Powder Wire Cross-Section Comparison Wire from this work, 200 -500 mm powder The Business of Science® Wire from old work, 100 -500 mm powder Ø No significant difference in fill factor between wires made of old and new powders. Ø Some hard particles were observed in the new wires, none in the wires made before 2007. © Oxford Instruments 2013 CONFIDENTIAL Page 6
Wire Performance Comparison The Business of Science® Ø The JE performance is the similar in all three billets, showing that slightly better Ø The JE performance is similar for all three billets, on wire PMM 130723 -2 by the granulated powder with particle size of 200 -500 m. Ø Jc is clearly higher in wires with the granulate powder. © Oxford Instruments 2013 CONFIDENTIAL Page 7
Hard Particles Observed in New Wires The Business of Science® Ultra fine powder, ~1 m) 0. 8 mm wire (granulated powder, 100 -200 mm) Ø Hard particles are observed in all three new wires and the higher frequency of hard particles occurred in the wires with 1 mm and 100~200 mm powders. Ø Most of hard particle are 10~40 mm, not to causing wire breakage, but leading to filament merge. Some of them are slightly Bi-rich and Cu deficit. Ø Eliminating hard particle is important to keep wire uniformity and piece-length. © Oxford Instruments 2013 CONFIDENTIAL Page 8
Summary The Business of Science® Ø All three wires are fabricated into single piece without breakage. Ø The JE performance is similar for all three billets, but Jc is clearly better on wires made of granulated powder. Ø Hard particles were observed in all three wires. Ø Need to remove the hard particle. © Oxford Instruments 2013 CONFIDENTIAL Page 9
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