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SuperPower, Inc. is a subsidiary of Royal Philips Electronics N.V.

Second Generation High Temperature Superconducting Wire: Fabrication, Properties, and Potential ApplicationsAndrei Rar, Yi-Yuan Xie, Drew Hazelton, Yimin Chen, Xuming Xiong, Ed Zhang, and Venkat Selvamanickam

SR 2008, June 2008, Novosibirsk, Russia

Synchrotron Radiation 2008, Novosibirsk, Russia, June 2008

Acknowledgements

• SuperPower– To the rest of the SuperPower Team– 2G HTS Wire Development Program funding from Title III and DOE

through UT-Battelle

• National High Magnetic Field Laboratory at Florida State University

• Fermi National Accelerator Laboratory• Oak Ridge National Laboratory


Superconductivity 101

What is a Superconductor?

Superconductors exist in a region bounded by:

• Temperature (Tc)• Magnetic Field (Hc)• Current Density (Jc)


Two general classes of superconductors have been commercialized

“Low temperature” superconductors– Operation limited to low

temperatures near 4 K (LHe)– First commercial

superconductors– NbTi, Nb3Sn

“High temperature” superconductors– Operation from 4 K (LHe) to 77

K (LN2)– 1G: BSCCO-based– 2G: YBCO-based– 2G: thin film vs. wire drawing

processing– Moving from development into

commercialization

NbTi and Nb3Sn Superconductors (Luvata)

1G BSCCO-2223 Tape (AMSC)

2G YBCO Wire (SuperPower, Inc.)


Superconductivity is an enabling technology to move high energy density power

Current carrying capability of copper ~ 200 A/cm2

Current carrying capability of 2G superconductor film ~ 5,000,000 A/cm2 (Jc)

Liquid helium (4 K)

Conductor e.g. Copper

High TemperatureSuperconductor (HTS)

Resistance

Temperature

Low TemperatureSuperconductor (LTS)

Liquid nitrogen (77 K) RoomTemperature (300 K)

Zero resistance !!!

Current carrying capability of 2G superconductor wire ~ 50,000 A/cm2 (Je)


Structure and Main Processing Steps

Electropolishing Pilot IBAD Pilot Buffer

MOCVD

Copper Plate

20µm Cu

20µm Cu

Hastelloy substrate

HTS

LMO

Homo-epi MgO

IBAD MgO


Pilot Substrate Electropolishing

Pilot Buffer

SuperPower is unique in the world in having established operational 2G Pilot Manufacturing facilities

Pilot IBAD Pilot HTS


Remarkable progress in 2G wire scale-up over the last 5 years

020,00040,00060,00080,000

100,000120,000140,000160,000

Nov

-01

Jul-0

2

Mar

-03

Nov

-03

Aug-

04

Apr

-05

Dec

-05

Aug-

06

Apr

-07

Jan-

08

Crit

ical

Cur

rent

* Le

ngth

(A-m

)

62 m18 m1 m 97 m

206 m

1 m to 935 m in 5 years

Also, Ic doubled & speed

increased 12-fold to 180 m/h*

158 m

322 m427 m

595 m

10

100

1,000

10,000

100,000

1,000,000

May

-02

Oct

-02

Mar

-03

Aug

-03

Jan-

04Ju

n-04

Nov

-04

Apr

-05

Sep

-05

Feb-

06Ju

l-06

Nov

-06

Apr

-07

Sep

-07

Feb-

08

Crit

ical

Cur

rent

* Le

ngth

(A-m

)World Records

*4 mm speed equivalent

790 m

935 m


Long length processing of 2G HTS wire demonstrated

Speed of 4 mm tape (m/h)

Process (single pass)

360IBAD MgO

345Homo-epi MgO

345LMO

135MOCVD

050

100150200250300

0 100 200 300 400 500 600 700 800 900 1000

Position (m)

Cri

tical

cur

rent

(A

/cm

77 K, Ic measured every 5 m using continuous dc currents over entire tape width of 12 mm (not slit)

• Minimum Ic = 170 A/cm over 935 m • Ic x Length = 158,950 A-m• Uniformity over 935 m = 10.6%


Capability of ~ 1000 A in 12 mm widths achieved!

3.5 µm film made in 10 passes: Ic = 964 A = 803 A/cm (Jc = 2.06 MA/cm2)2.1 µm film made in 6 passes: Ic = 929 A = 774 A/cm (Jc =3.68 MA/cm2)

Ic measurement using continuous dc current (no pulsed current) across entire tape width of 12 mm No patterning

2005 SmYBCO

2006 SmYBCO

2007 GdYBCO

2008 GdYBCO

0100200300400500600700800900

0 1 2 3 4

Thickness (µm)

Crit

ical

cur

rent

(A/c

m-w

idth

)

Over 1.2 m length,Ic = 964 A = 803 A/cm

2005 SmYBCO

2006 SmYBCO

2007 GdYBCO

2008 GdYBCO

0

1

2

3

4

5

6

7

0 1 2 3 4

Thickness (µm)

Crit

ical

cur

rent

den

sity

(MA/

cm2 )


HTS application for “big science” - from SR to high energy physics

• LN2 magnets

• High field LHe magnets

• Current limiters

• Currents leads

• Cables with high current density


High Field Coil Demonstrated – 2.4T at 64K

0

2

4

6

8

10

12

0 10 20 30 40 50 60Current (A)

Cen

tral

Fie

ld (k

G)

First TestLast Testmodel

77 K

0

5

10

15

20

25

0 20 40 60 80 100 120Current (A)

Cen

tral

Fie

ld (k

G)

First Test

Last Test

64 K

1.1 T Coil at 77 K !

2.4 T at 64 K


Collaboration with FermiLab (4mm wide, SCS)

0

200

400

600

800

1000

1200

1400

1600

0 2 4 6 8 10 12 14 16

B[T]

Ic[A

]

33 K 22 K 14 K 4.2 K Low Temp 33 K //22 K //14 K //4.2 K //4.2 K // sample 2Low Temp // sample 24.2 K // sample 3Low Temp // sample 3


FermiLab’s comparison of different wire types


2G YBCO HTS offers distinct advantages in high magnetic field current density over “traditional” LTS wire

100

1000

10000

100000

0 5 10 15 20 25 30 35

Applied Field ( Tesla )

non-

Cu J

c ( A

/mm

2 )

YBCO (H//c) YBCO (H//ab) NbTi

Nb3Sn (Internal Sn) Nb3Sn (Bronze)

YBCO Data by Z. Chen at NHMFL / FSU (2007)


0

50

100

150

200

250

300

350

400

450

-20 0 20 40 60 80 100 120

Angle (degree)

Ic (A

/cm

)

3.5micron recipe-02.8micron recipe-13.3micron recipe-2*

77K, 1T

Dramatic improvements achieved in in-field performance of our 2G wire

For 3.3micron film of recipe-2*Ic_minimum(77K, 1T) = 185.6A/cmIc_minimum(65K, 3T) = 267.3A/cmIc(77K, B//c=3T) = 71.8A/cm

0

20

40

60

80

100

120

140

160

180

-20 0 20 40 60 80 100 120

Angle (degree)

Ic (A

/cm

)

0.7micron recipe-00.7micron recipe-10.7micron recipe-2*

77K, 1T

Data from Y. Zhang, M. Paranthaman, A. Goyal, ORNL

Best in-field performance in commercial 2G wires

For 0.7micron recipe-2*Recipe-1: strong pinning for B//abRecipe-2*: strong pinning for B//c


Mechanical properties of 2G wire are ideal for high field, high stress applications

< 0.35 @ 0.4%Nb3Sn, 16 T

< 0.68 @ 0.4%Nb3Sn, 12 T

< 0.82 @ 0.4%Nb3Sn, 8 T

< 0.90 @ 0.4%Nb3Sn, 4 T

> 0.95 for ε ~ 0.35%

1G low strength

> 0.95 for ε ~ 0.40%

1G high strength

> 0.95 for ε ~ 0.45%

SP 2G

Ic / Icε=0Conductor

Ic retention vs. strain Comparative Operating Stress-Strain Operating Windows for High Field Superconductors

0

200

400

600

800

0 0.1 0.2 0.3 0.4 0.5

Strain (%)

Stre

ss (M

Pa)

SP 2G HTSHigh Je

High Strength 1G HTS Low Je

Nb3Sn Moderate JeLow Strength

1G HTSModerate Je


NHMFL facilities provide 19T axial background field

Insert coil tested in NHMFL’s unique, 19-tesla, 20-centimeter wide-bore, 20-megawatt Bitter magnet

2G HF Insert Coil Showing Terminals, Overbanding and Partial Support Structure. Flange OD is 127 mm.


2G high field insert coil demonstration

~1.569 A/mm2 per ACoil Je

~ 2772# of turns

~ 44.4 mT/ACoil constant

~ 462 m2G tape used

12 (6 x double)# of Pancakes

~ 51.6 mmCoil Height

~ 87 mmWinding OD

19.1 mmWinding ID

9.5 mm (clear)Coil ID

Wire Specifications: Dimensions: 4 mm wide x

95 microns thickSubstrate: 50 micron Hastelloy

HTS: ~ 1 micron YBCO

Stabilizer: ~ 2 micron Ag on YBCO

~ 20 microns of surround copper stabilizer per side

Tape Ic 72 – 82 A, 77 K, sf

Coil Winding:

Double Pancake Construction

Dry Wound (no epoxy)

Kapton polyimide insulation (co-wound)

Overbanding: 316 Stainless Steel


High field insert coil achieves world records for highest HTS field, highest magnetic field by a SC magnet

0.0

5.0

10.0

15.0

20.0

25.0

30.0

0 50 100 150 200 250

Current (A)

Cent

ral F

ield

(T)

19T background self field

3.2 T4.2K Peak Radial Field @ Ic, self field

2.7 T4.2 K Peak Radial Field @ Ic, 19 T bkgd (axial)

274.6 A/mm24.2 K Je @ Ic, 19 T background (axial)

9.81 T9.81 T4.2 K Central field – self field

26.8 T26.8 T4.2K Central Field – 19 T background (axial)

485,1004.2 K Amp Turns @ Ic –19 T background (axial)

175 A 4.2 K Coil Ic – 19 T background (axial)

346.7 A/mm24.2 K Je @ Ic, self field

612,6124.2 K Amp Turns @ Ic-self field

221 A4.2 K Coil Ic - self field

72 A – 82 A (77K, sf)

Ic of Tapes in Coil

26.8 T @ 175 A

9.81 T @ 221 A

Peak hoop stress ~ 215 MPa, well below tape limit


Thin-profile wire (50 micron substrate) exhibits superior bend properties in joints & splices

• 4 mm wide conductors each with 20 µm surround copper stabilizer• Joint or splice length = 3 or 3.5 cm• Original tape thickness = 0.095 mm• Thickness at joint or splice = 0.22 mm (~ 2 times thinner that with 1G or other 2G!)

No degradation in Ic (1 µV/cm) over the joint or splice Joint or splice resistivity = 40 to 50 nΩcm2

No degradation in Ic and resistivity when joint or splice is bent over down to 1”diameter and thermal cycled three times. Ic was tested at every thermal cycle

Joint

Splice

Copper stabilizer

substrateYBCO

solder

In 2005 tested single tape only.In 2006 tested joints & splices


Current Leads ComparisonBaseline:

Current: 100 ATemperature: 77 K to 4.2 K

Type Heat LeakOptimized non-SC lead, non-vapor cooled: 1.2 WOptimized non-SC lead, vapor cooled: 0.092 W1G alloyed Ag HTS lead (1), non-vapor cooled, 0.25 m long: 0.018 W2G Ag HTS lead (2), non-vapor cooled, 0.25 m long: 0.013 W2G alloyed Ag HTS lead (3), non-vapor cooled, 0.25 m long: 0.0008 W

– All values assume top end anchored at 77K– Vapor cooling of HTS leads will reduce the heat leak significantly below the values stated– Heat leak with HTS leads scales as 1/Length(1) 1G tape, 4.2 mm x 0.22 mm, 65% Ag-4 wt% Au(2) 2G tape, 4 mm x 0.053 mm, 50 µm Hastelloy® C276 substrate with 2 µm thick Ag cap layer (no Cu)(3) 2G tape, 4 mm x 0.053 mm, 50 µm Hastelloy® C276 substrate with 2 µm thick Ag-4 wt% Au cap layer, (no Cu)


-100

-80

-60

-40

-20

0

20

40

60

80

0 20 40 60 80 100

Time [ms]

Cur

rent

[kA

]

-2.0

-1.0

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

Volta

ge a

cros

s H

TS

elem

ents

[kV]

Iprospective I_total_KEMA I_HTS Ish V_total_KEMA

-5.0-4.0

-3.0-2.0-1.00.0

1.02.03.0

4.05.0

2 4 6 8 10 12 14 16 18 20

Time [ms]

Cur

rent

[kA

]

-1.0-0.5

0.00.51.01.5

2.02.53.0

3.54.0

Volta

ge a

cros

s H

TS

elem

ents

[kV]

I_total_KEMA I_HTS Ish V_total_KEMA

Quench speed around 0.5 ms

2G Wire for SFCL shows consistent, excellent performance

< 1 msResponse time

3 kAPeak current through element

90 kA*Prospective current

32 kALimited current

NarrowElement quality range

2G High-power SFCL test

Fast response time


3-in-One Cable Design• Compact size (O.D. = 135mm) (5.3”)

HTS Conductor and Shield Winding• Di-BSSCO wire (Long length, High-Ic, High-strength,

anti-ballooning)• Equal current distribution to minimize AC loss• Cancel magnetic field EMI free

Electrical Insulation• PPLP with high dielectric strength & small tangent loss

Fault Current Protection• Cu former and shield windings to handle 2nd

contingency fault conditionsThermal Contraction

• 3-cores are loosely stranded to accommodate 0.3% contraction

Thermal Insulation• Stainless steel cryostat for low heat inleakage

[Shipping Test Results] Critical Current1.8 kA (at 77K ,DC) same as designVoltage Test (based on AEIC) AC: 69kV ・10min (no PD)Imp: +/- 200kV, 10 shots/eachAC loss0.7W/m/ph (at 0.8kA) same as designCable Bending Test (18；1.2ｍR)No Ic degradationNo defect in HTS wires and electrical insulations

Structure and Properties of Albany BSCCO Cable

HTS Conductor（2-layer）

HTS Shield（1-layer）

Cu Shield

135 mm35 mm

Electrical Insulation（PPLP +Liquid Nitrigen）

Cu Stranded Former

Tension Member

Stainless Steel Double Corrugated

Cryostat

HTS Conductor（2-layer）

HTS Shield（1-layer）

Cu Shield

135 mm35 mm

Electrical Insulation（PPLP +Liquid Nitrigen）

Cu Stranded Former

Tension Member

Stainless Steel Double Corrugated

Cryostat


We have not reached the limit of 2G HTS wire capability, but our HTS wires are ready NOW for a number of magnetic and other high tech applications.

SummaryAre you ready …

for 2G HTS?


Questions?

Thank you for your interest!

For further information about SuperPower, please visit us at: www.superpower-inc.com

or e-mail: [email protected]

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