1. Thermomechanical Processing of High T c Superconducting Wire Super BSCCO Family Y. King S. Maltas B. Cooper C. Bjelkengren

2. Super BSCCO Family 2 Project Goal Improve critical current through BSCCO- 2223 ceramic encased in a silver tape. Strategy → Improve texture

3. Super BSCCO Family 3 Texture Analysis Why is texture important?

4. Super BSCCO Family 4 Texture Analysis Why is texture important? Current flows along Cu-O planes

5. Super BSCCO Family 5 Texture Analysis Why is texture important? Good Bad Worst

6. Super BSCCO Family 6 Project Goal Strategy Choose most effective thermomechanical processing How? – Evaluate  Ic 150 A  Texture Squeeze out the voids – area fraction from SEM Lotgering factor – F-factor from XRD

7. Super BSCCO Family 7 Gantt Chart 1234567891011121314 Characterization Cold Rolling Uniaxial Cold Deformation Heat Treatment Hot Isostatic Pressing Directional Grain growth Ideas For Application/Prototype Improve Superconductivity, Jc Work On Final Product Final Presentation/Poster

8. Super BSCCO Family 8 2223-BSCCO Properties ST 0.22 mm 4.14 mm Volume % ~ 60 % BSCCO T c : 110 K B c : 10 -2 T I c : 110 A A cross section ~ 0.9 mm 2

9. Super BSCCO Family 9 Critical Current Measurement

10. Super BSCCO Family 10 Critical Current Measurement

11. Super BSCCO Family 11 Critical Current Measurement I C = 110 A A total = 4.14 x 0.22 mm 2 A BSCCO = 60 % A total J E (engineering current density) = I C / A total = 121 A/mm 2 J C (critical current density) = I C / A BSCCO = 200 A/mm 2

12. Super BSCCO Family 12 Texture Analysis How do we measure texture? Qualitative: SEM examination of physical grain alignment, and size and concentration of voids. Answers the question: Do visual changes correlate to actual improvements in Ic ?

13. Super BSCCO Family 13 Texture Analysis - SEM Courtesy: Justin Schwartz (FAMU-FSU)

14. Super BSCCO Family 14 Texture Analysis How do we measure texture? Quantitative: X-Ray Diffraction Lotgering Factor, F, which can be calculated: F = (P – Po) / (1-Po)

15. Super BSCCO Family 15 Texture Analysis - XRD Courtesy: Justin Schwartz (FAMU-FSU)

16. Super BSCCO Family 16 Project Goal Strategy Methods for improving texture:  Rolling (hot or cold)

17. Super BSCCO Family 17 Rolling (hot and cold) l 1 = 2.02 x l 0 w 1 = 1.05 x l 0 t 1 = 0.47 x t 0

18. Super BSCCO Family 18 Project Goal Strategy Methods for improving texture:  Uniaxial deformation (hot or cold)

19. Super BSCCO Family 19 Uniaxial Tensile Test (hot and cold) Y S of Ag: 1.4 x 10 8 Pa x-section: 9.1 x 10 -7 m 2 F applied: 127.5 N

20. Super BSCCO Family 20 Project Goal Strategy Methods for improving texture:  Hot isostatic pressing

21. Super BSCCO Family 21 Hot Isostatic Pressing t ~ 40 hours T ~ 400/500 o C P ~ 70 MPa Ag-based solder Annealing to reestablish O x

22. Super BSCCO Family 22 Hot Isostatic Pressing T t 500 o C 40 h - Pressure, Temperature, time -Thermal diffusivity of oxygen across Ag - Annealing 70 MPa

23. Super BSCCO Family 23 Project Goal Strategy Methods for improving texture:  Directional grain growth

24. Super BSCCO Family 24 Directional Grain growth T = 860 o C T = 760 o C v = ?

25. Super BSCCO Family 25 Option: Bonus Prototype