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

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

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

6. HTS –perovskite ceramicsCu O Ba Y
B 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. American Superconductor 55 filament (B2223) tape
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 variability32 30
> 150 m lengths
Manufacturing Campaign for Detroit Edison
Manufacturing Campaign for Customer X (2002) 28 26 24 22 20 18
Frequency 16 14 12 10 8 6 4 2
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 Measured at AMSC & UW University of Wisconsin21
Measured at AMSC and
University of Wisconsin
Measured at AMSC & UW
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 $/kA.m
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
Reduced Manufacturing Costs ($/m) and Increased Wire Performance (current carrying capacity)

18. 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
Bought and shut down by AMSC in 2002

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
Flux Density, B (T)

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

22. Key issues for power applications
Overall current density Je of 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

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. Magnesium Diboride Mg B s
39K p

25. Magnesium Diboride
~ 400 $/kg

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

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

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

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

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

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

32. Strain Effect on MgB2 long tape 100 h ball milled
Strain gauges
Modified Walters Spiral (WASP)
MgB2 Tape
d=26 cm
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 amps.
Hyper Tech Research

36. First test of an MgB2 pancake
BSCCO
250
MgB
pancake 2
BSCCO pancake
MgB2
200
150
4.2 K
Critical Current [A]
100 50
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
Peter Lee’s Cosmic Plot (UW/ASC) 10 1
Genoa
25 K
Power Apps
30 – 77 K
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
                                                         
                                                    
                                                          
                                                           
YBCO precursor
YBCO oxygenation and 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 $/kA.m
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
Reduced Manufacturing Costs ($/m) and Increased Wire Performance (current carrying capacity)

49. AMSC 2G Plant 25th Sept. 2003 1st October 2003 3rd October 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
Effort
Performance

51. Power Technologies HTS g2 75y 17y MgB2 Performance HTS g1 Copper-Iron
2003
Effort

52. Conclusions: Superconductors for Motors
HTS G1:
B2223 tape
Diboride:
MgB2 wire
MgB2 HIPped bars
HTS G2:
YBCO CC tape
YBCO cast crystals