Thermomechanical Processing of High Tc Superconducting Wire

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Thermomechanical Processing of High Tc
Superconducting Wire

• Super BSCCO Family
• Y. King
• S. Maltas
• B. Cooper
• C. Bjelkengren

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Project Goal

• Improve critical current through BSCCO-2223
  ceramic encased in a silver tape.
• Strategy ? Improve texture

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Gantt Chart
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Ic Measurement Original Unprocessed

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Cold Rolling
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Ic Measurement Cold Rolled and Annealed (800ºC)
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Directional Grain growth

800ºC 200 ºC
Room Temperature
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Ic Measurement Cold Rolled and Directional
Grain Growth
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Ic Measurement Unprocessed Tape
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Future Action

• Processes to Pursue
• Hot Rolling
• Directional Grain Growth
• Hipping
• Annealing in Partial Oxygen (may be added to
  above processes)

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Future Action Cause for Failure

• Determine Failure Step
• Our samples were treated (e.g. cold rolled) and
  then anneal in air at 800 deg C.
• Did cold rolling break up the 2223 grains?
• Did annealing in air instead of in an oxygenated
  environment cause the formation of different,
  less conductive phases?
• SEM was microstructure/texture ruined?
• XRD did we precipitate new phases?
• XRD make stacks of long transverse

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Future Action Hot Rolling

• Hot rolling gt Cold Rolling (Range 200-300ºC)
• Hot Rolling Prevents Breaking of Brittle 2223
• Already contacted Peter Stahle about hot rolling
  equipment.

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Future Action Temperature Gradient

• Temp Gradient Equipment
• Increase in Texture Likely
• Contact Prof. Flemings about better equipment

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Future Action Annealing

• Annealing Equipment
• Add oxygen to furnace at 800ºC and air quench
• Oxygen Partial Pressure (7.53) gt than in air

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Future Hipping

• Last Step because of Constraints
• Contact Representatives to Set Up Date

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