Round multifilamentary high T_c Bi₂Sr₂CaCu₂O_x/Ag superconducting wires for high field magnets. Phase I Final Report

Technical Report · Fri Jun 21 00:00:00 EDT 2019

OSTI ID:1572388

Sengupta, Suvankar ^[1]; Revur, Ramachandra R ^[1]; Kopulwar, Utkarsh ^[1]; Huang, Yibing ^[2]; Jiang, Jianyi ^[3]

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1. MetaMateria Technologies
2. B-OST
3. Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab. (MagLab)

The overall objective of the Small Business Research Program is to develop a reliable high quality Bi-2212 powder suitable for demonstration scale (> 1km lengths) multifilamentary round wires for magnets with fields above 15 T. For heat treating long length of wires, cables and magnets (or coils), the processing window needs to be increased. In an attempt to increase J_E and the processing heat treatment window of multifilamentary Bi-2212/Ag wires the impact of secondary phase (AEC) is investigated. During Phase I, the primary emphasis was given to produce powders with well dispersed (14,24)AEC particles. Two approaches were investigated. Optimization of processing parameter during Phase I resulted in a Bi-2212 with well dispersed AEC particles. DTA studies reveal that the solidification behavior changes with increasing amount of AEC phase. Two powder made with composition (~Bi2212 with 1 wt% AEC) was down selected and shipped to B-OST for wire fabrication. Multifilamentary Bi-2212/Ag with configuration 55 x18 are fabricated to diameter 0.8 mm-1.2 mm. The filaments are found to be uniform with no significant filament merging showing good powder homogeneity. The performance of the wires is comparable to the Nexan Benchmark used at B-OST. Wires are also OP processed at NHMFL. A JE (4.2 K,5 T) of 853 A/mm² and 1022 A/mm² was observed in the wires PMM190422 and PMM190518 wires respectively. The wires are treated with standard processing parameters used in OP processing. Further heat treatment optimization work is in progress. The Phase I results demonstrate the potential of the approach; however, further refinement is needed to realize the overall goal of the program which will be done in Phase II. During Phase II, the composition (amount of secondary phases) required to improve processing (heat treatment) window and JE at high magnetic fields in Bi-2212/Ag multifilamentary wires will be optimized. The heat treatment conditions to further refined to reduce size (primary particle size) of the AEC particles used as seeds in processing approach 1. The heat treatment equipment, including the mantle structure to minimize any possibility of contamination of powder in the furnace during heat treating will also be developed. Heat treatment conditions of the Bi-2212/Ag wires will be optimized to maximize the potential of the approach

• Research Organization: MetaMateria Technologies
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: SC0018664
• OSTI ID: 1572388
• Type / Phase: SBIR (Phase I)
• Report Number(s): Final Report -DE-SC0018664
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
36 MATERIALS SCIENCE
43 PARTICLE ACCELERATORS
The overall objective of the Small Business Research Program is to develop a reliable high quality Bi-2212 powder suitable for demonstration scale (> 1km lengths) multifilamentary round wires for magnets with fields above 15 T. For heat treating long length of wires
cables and magnets (or coils)
the processing window needs to be increased. In an attempt to increase JE and the processing heat treatment window of multifilamentary Bi-2212/Ag wires the impact of secondary phase (AEC) is investigated. During Phase I
the primary emphasis was given to produce powders with well dispersed (14
24)AEC particles. Two approaches were investigated. Optimization of processing parameter during Phase I resulted in a Bi-2212 with well dispersed AEC particles. DTA studies reveal that the solidification behavior changes with increasing amount of AEC phase. Two powder made with composition (~Bi2212 with 1 wt% AEC) was down selected and shipped to B-OST for wire fabrication. Multifilamentary Bi-2212/Ag with configuration 55 x18 are fabricated to diameter 0.8 mm-1.2 mm. The filaments are found to be uniform with no significant filament merging showing good powder homogeneity. The performance of the wires is comparable to the Nexan Benchmark used at B-OST. Wires are also OP processed at NHMFL. A JE (4.2 K
5 T) of 853 A/mm2 and 1022 A/mm2 was observed in the wires PMM190422 and PMM190518 wires respectively. The wires are treated with standard processing parameters used in OP processing. Further heat treatment optimization work is in progress. The Phase I results demonstrate the potential of the approach
however
further refinement is needed to realize the overall goal of the program which will be done in Phase II. During Phase II
the composition (amount of secondary phases) required to improve processing (heat treatment) window and JE at high magnetic fields in Bi-2212/Ag multifilamentary wires will be optimized. The heat treatment conditions to further refined to reduce size (primary particle size) of the AEC particles used as seeds in processing approach 1. The heat treatment equipment
including the mantle structure to minimize any possibility of contamination of powder in the furnace during heat treating will also be developed. Heat treatment conditions of the Bi-2212/Ag wires will be optimized to maximize the potential of the approach