1. Superconductivity UK Commercial superconductorsfor motors and generators Dr. Philip Sargent, Diboride Conductors Ltd.

2. Commercial Wire & Tape • Commercial production: • Niobium alloys (NbTi, Nb3Sn etc) • B2223 / silver tape - 1st Generation HTS • Pre-commercial: • MgB2 • Industrial laboratory: • YBCO 2nd Generation HTS “coated conductor”

3. HgBa2Ca2Cu3O9 (under pressure) 160 140 HgBa2Ca2Cu3O9 TlBaCaCuO 120 B2223 - Bi2Sr2Ca2Cu3O 100 YBCO - YBa2Cu3O7 Liquid Methane LNG (112K) Liquid Nitrogen (77K) 80 60 40 (La, Ba) Cu) MgB2 Nb3Ge Nb3Sn NbN 20 NbC Nb Pb Hg V3Si 1910 1930 1950 1970 1990 Superconductors Tl, Hg…(138K) Transition temperature (K) Leigh Jarvis

4. More superconductors YPd2B2C HoMo6S8 (Chevrel) ErRh4B4 CeRu2 heavy fermion 1991 - K3C60 Fullerene 1994 - Sr2RuO4 2001 – MgB2 2001- C nanotubes 2002 - PuCoGa5 (18K) 1980- (TMTSF)2PF6 Nature 6 Mar.2003 - Na0.35CoO2•1.3H2O

5. HTS –complex copper oxides YBCO - YBa2Cu3O7 B2223 - Bi2Sr2Ca2Cu3O

6. Cu Ba O Y Ba HTS –perovskite ceramics B2223 - Bi2Sr2Ca2Cu3O YBCO - YBa2Cu3O7

7. Engineering Implications • Requires near single-crystal microstructure by complex processing, • Oxide requires furnace treatment in controlled oxygen atmosphere, in silver, • Highly anisotropic resulting tape: • Along and across tape, • Sensitive to magnetic field direction!

8. B2223 multifilamentary tape -1 • Fill silver tube with precursor powders. • Reduce by extrusion, swaging, drawing and rolling to a mono-filament aligned-crystal wire. • Restack bundle in another silver tube.

9. B2223 multifilamentary tape -2 • Draw multifilament • Draw to align crystals • Roll to tape • Furnace heat treat

10. AMSC & Sumitomo • AMSC & Sumitomo have a reciprocal licensing agreement American Superconductor 55 filament (B2223) tape Sumitomo (B2223) tape

11. AMSC B2223 Manufacturing Plant • Larger billets, Process automation, Longer strands, Multi-dies, Faster line-speed, Combination of process steps • Began volume production in early 2003 • Full capacity could be 20,000 km/year, now 900 km/year

12. (B2223) Critical Currents 2001-02 Manufacturing variability 32 Manufacturing Campaign for Detroit Edison > 150 m lengths 30 Manufacturing Campaign for Customer X (2002) 28 26 24 22 20 18 Frequency 16 14 12 10 8 6 4 2 0 100 103 105 108 110 113 115 118 120 123 125 128 130 133 135 138 140 143 145 148 150 End to End Critical Current, Amps 170 A also demonstrated in short lengths

13. B2223 Wire Improvement 21 Measured at AMSC & UW University of Wisconsin Measured at AMSC and University of Wisconsin 20 19 18 17 Jc (A/cm2, 77 K, 0.1T, //c) 16 15 14 13 12 1994 1995 1996 1997 1998 1999 2000 2001 2002 • Jc of 19.8kA/cm2 (77K, 0.1T, //c):a new level of performance for wire with production architecture • Measurement in 0.1 T field avoids self-field current suppression

14. Current Distributions in B2223 180 kA/cm2 Regions Observed in AMSC Monocore Tapes Headroom for Further Current Density Progress (U. Wisconsin/AMSC)

15. AMSC B2223 Plant History • Development started in summer 1988 • 10 years (1998): • AMSC produces 20 km in 200 m lengths with an average current of 90 A at 77 K • 14 years: 900km/y plant fully operational • 15 years: 900km/y plant & B2223 IPR value of $22m written off !

16. Price/Performance $/kA.m • How much does it cost to buy the wire to carry 1000 Amps a distance of 1m? • Copper: 6 $/kA.m – 22 $/kA.m depending on current density (400 – 100 A/cm2) • Superconductors typically quoted at Jc and at 77K and either zero magnetic field or “self field”. • Cryogenic OFHC copper can be 0.06 $/kA.m. • NbTi is approx. 0.9 $/kA.m in liquid helium.

17. Price/Performance $/kA.m 1200 $/kA.m 1000 800 Price/Performance Ratio, $/kA-m 600 World’s First HTS Wire Manufacturing Plant Opened By AMSC 400 200 200 $/kA.m 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Reduced Manufacturing Costs ($/m) and Increased Wire Performance (current carrying capacity)

18. Bought and shut down by AMSC in 2002 B2223 & Commercial Products • At $50/kAm (77K) price/performance ratio significant markets would be enabled (it was thought in ~1999): • Utility Generators (>100MVA) • Ship Propulsion Motors and Generators (>5MW) • Wind Turbine Generators (>4MW) • Urban T&D Power Cables • Industrial Magnetic Processing • Significant worldwide industry in B2223 American Superconductor, Innova, Nordic Superconductor, Sumitomo Electric, Vacuumschmelze, Trithor

19. Magnetic Field • High magnetic field reduces current carrying capacity • Lower temperatures enhance current carrying capacity • B2223 must operate 20K – 40K for motors which have fields ~ 2T • B2223 at 27K carries twice the current, so $/kA.m reduces to 100 $/kA.m.

20. Saturation in Fe-3%Si at 1.6T 1.6 Flux Density, B (T)

21. 1.6T Power Apps 30 – 77 K Peter Lee’s Cosmic Plot (UW/ASC) MA/cm2 10 1 0.1 Copper: up to 400 A/cm2 0.01 0.001

22. Overall current density Jeof conductor, not just of superconductor Performance in field Multiple filaments for AC applications Anisotropy of Jc with respect to field direction Cost! Conductor itself Cooling (AC losses) Scalability of fabrication Mechanical Strength, bend radius Conductor shape tape or wire or new motor designs Key issues for power applications

23. Diboride & YBCO • YBCO and similar compounds have had research worth $$billions devoted to their physics and processing. • MgB2 was discovered in January 2001; physics now entirely understood. • Both can be made in: • Tape geometry • Massive lumps for new motor designs

24. Mg B Mg B Mg B Mg Magnesium Diboride s 39K p

25. Magnesium Diboride ~ 400 $/kg

26. Tube filling with MgB2 reacted powders Wire drawing and/or rolling Flat rolling Long lengths can be now fabricated Cu-sheathed tape transverse cross section irregular cross section Making Diboride tape Simple sintering ~700C

27. reaction sintering 23% porosity IN-SITU EX-SITU simple sintering tube filling 100m lengths of tape PIT Processing routes for the fabrication of MgB2 wires B Mg IN-SITU + a) MgB2 EX-SITU b) draw to wire

28. Powder in Tube Swege Flat rolling F = 3.85 mm Tape 4 x 0.38 mm2 P. I. T. Fin= 5 mm Fout= 8 mm Draw Ball milling under Ar F = 2 mm P.I.T. Final Tape MgB2 Flat rolling Université de Genève

29. HyperTech CTFF for MgB2 CONTINUOUS TUBE FORMING AND FILLING (CTFF)

30. L. Cowey et al., MgB2 + yttria Irreversibility field • Increase magnetic field capability by metallurgy • Create pinning defects by controlled alloying of MgB2

31. T CSAM Texas Center for Superconductivity and Advanced Materials University of Houston NASA Commercial Space Center 10-Meter Long Square MgB2 Wire

32. Modified Walters Spiral (WASP) MgB2 Tape Strain gauges d=26 cm Strain Effect on MgB2 long tape 100 h ball milled Université de Genève

33. In situ B+Mg with Fe barrier in Monel Sheath With iron –tough to make multifilament- most likely be cabled , (twisted) monofilaments for low AC loss conductor, working on Outer sheaths of Monel, Cu/Ni, and Cu to improve stabilization. Hyper Tech Research

34. Reasonable properties can be obtained with all Cu wires, Or with with Nb barriers in Cu. Multifilament wires can be made Hyper Tech Research

35. Shows ITER barrel wound with over 1 meter of MgB2 wire, all Cu sheath, 1.00 mm diameter wire. The self field transport current for the coil at 4.2 K was 450 amps, the estimated transport current at 20 K would be 150-180 amps. Hyper Tech Research

36. BSCCO MgB2 First test of an MgB2 pancake 250 MgB pancake 2 BSCCO pancake 200 150 4.2 K Critical Current [A] 100 50 0 3.0 3.5 4.0 4.5 5.0 Magnetic Field [T]

37. Genoa 25 K Power Apps 30 – 77 K Peter Lee’s Cosmic Plot (UW/ASC) MA/cm2 10 1 0.1 0.01 0.001

38. Magnesium Diboride (MgB2 ) • Advantages • No weak-link effects, low anisotropy • Easy to fabricate wires, films: <$10/kA.m potential • Challenges • Tc < 40 K (77 K applications like cables, transformers not viable) • High field applications such as NMR not viable • Possible applications in 20-30K range for modest field environments, e. g., rotating machinery

39. YBCO Coated Conductor • Rolled, textured Nickel tape (Ni-W) • Oxide buffer layer, preserves texture • YBCO (or analogue, e.g. HoBCO), preserves texture • Near “single crystal” 100s of metres long • <$10/kA.m potential

40. YBCO Coated Conductor Sumitomo YBCO-CC

41. YBCO Ni tape Oxide buffer layer deposition

42. YBCO YBCOprecursor YBCO oxygenationand conversion

43. YBCO Slitting

44. YBCO Coated Conductor tape • Active programs in US, Japan and Europe • Examples of results in 2001: • 122 A (75 K) over 1 m by LANL • World record for meter length • 50 A over 10 m by Fujikura • World record for 10 meter length • Over 60 m :Fujikura • World’s longest processed tape

45. Comparative Development • YBCO CC • Fujikura announces YSZ-IBAD process, early 1991 • Ten years later (2001): • Fujikura produces 10 m with 50 A (77 K) • B2223 • Work started in summer 1988 • Ten years later (1998): • AMSC produces 20 km at minimum 200 m piece length with an average current of 90 A (engineering current density 11,000 A/cm2 at 77 K)

46. YBCO CC Technical Issues • Adequate uniformity over length • Stability to over-currents or cracks • Adequate current in MOD films • Mechanical properties – spalling, cracking • Stability of metal-oxide epitaxial interface • Deposition rate for ion beam and laser processes • Thicker than 3 micron YBCO ? • …but must have that 10 $/kA.m process!

47. B2223 (1G) to YBCO (2G)

48. Price/Performance $/kA.m 1200 $/kA.m 1000 800 Price/Performance Ratio, $/kA-m 600 World’s First HTS Wire Manufacturing Plant Opened By AMSC 400 200 200 $/kA.m 0 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Reduced Manufacturing Costs ($/m) and Increased Wire Performance (current carrying capacity)

49. AMSC 2G Plant • 25th Sept. 2003 • ORNL award of $2.5m to AMSC to commercialise 2G process • 1st October 2003 • First tranche of $10m from US DoD and DOE to build 2G plant for YBCO-CC tape over 3 years. • 3rd October 2003 • $44m share issue priced to be used to build 2G plant • but all committed on pre-commercial processes!

50. Technology ‘S’ Curves Performance Effort