superior performance.powerful technology.

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

Recent Results in 2G HTS Wire Technology Development at SuperPower

Program funding from Title III and DOE through UT-Battelle & AFRL. Supported by CRADAswith Oak Ridge, Los Alamos, and Argonne National Laboratories

Yi-Yuan Xie, Y. Chen, X. Xiong, X. Zhang, A. Rar, M. Martchevskii, Y. Qiao, A.Knoll, K.P. Lenseth, R.M. Schmidt, J. Herrin, D. Hazelton and V. Selvamanickam

Korea Superconductivity Society Annual Meeting, July 9-11, 2008

KSS 2008, July 9-11, 2008

SuperPower 2G HTS wire utilizes high strength substrates coupled with high throughput processing

• SuperPower’s 2G HTS wire is based on a high throughput thin film manufacturing approach permitting a wide choice of materials combinations

– Advantages include high strength, low ac loss (non-magnetic, high resistivity substrates) and high engineering current density (ultra-thin substrates)

• High throughput is critical for low-cost 2G wire to enable early commercial adoption

– IBAD-MgO based buffer technique– MOCVD for HTS layer: combination of high deposition rate and large deposition

zone 2 μm Ag

20μm Cu

20μm Cu50μm Hastelloy substrate

1 μm HTS

< 0.1 mm

< 0.2 μm Buffer stack}

KSS 2008, July 9-11, 2008

SuperPower’s 2G pilot manufacturing facility has been operational since 2006

Pilot Substrate Electropolishing

Pilot buffer Sputtering

Pilot MOCVD

• Majority of investment already made for 1000 km/year capability

Pilot IBAD

KSS 2008, July 9-11, 2008

SuperPower was the first and is still the only company to demonstrate pilot-scale 2G HTS wire manufacturing• In Dec. 2006, SuperPower delivered nearly

10 km of 2G HTS conductor in 2006 to build a 30 m long cable for the Albany Cable project, which is now the world’s first & only 2G device energized in the power grid.

• Largest single quantity of 2G delivery

• 225 segments delivered each with a piece length of 43 m – not a delivery of tapes from laboratory runs !

Albany Cable project: National Grid, 350 m long cable. World’s first in-grid cable, first underground cable, first cable-to-cable joint.

30 m 2G cable segment

Excellent demonstration of reproducibility & manufacturing viability of our processes

KSS 2008, July 9-11, 2008

30 m long, 3-phase, fully-shielded 2G cable constructed with SuperPower 2G wire

35 mm

Copper tapes2 layers of 2G conductorPPLP (thickness 4.5 mm)3 layers of 2G conductor

Stranded Cu wires with insulation (φ16 mm / 140 mm2）

HTS conductor

Core outer diameter

Protection layerHTS shield

Electric insulation

Former

Cu StrandedWire Former

Electric Insulation(PPLP + Liquid Nitrogen)

Stainless Steel DoubleCorrugated Cryostat

Cu Shield2G HTS(2 shield Layers)

2G HTS(3 conductor Layers)

135 mm

KSS 2008, July 9-11, 2008

2G wire cable winding 3 core stranding

2G cable was fabricated under nearly the same conditions as 1G cable previously made for Albany Cable project

30 m 2G cable manufactured & tested by Sumitomo with ~10,000 m of SuperPower 2G wire

KSS 2008, July 9-11, 2008

2G cable shows excellent critical current performance in all layers

-0.5

0

0.5

1

1.5

2

0 500 1000 1500 2000 2500 3000Current (A, DC)

Elec

trica

l Fie

ld(u

V/cm

)

Core-1Core-2Core-3

Ic Criterion (1uV/cm)

Ic of conductor layers ~ 2660 – 2820A (DC, 77K, 1μV/cm)Ic of shield layers ~ 2400 – 2500A (DC, 77K, 1μV/cm)

-0.5

0

0.5

1

1.5

2

0 500 1000 1500 2000 2500 3000Current (A, DC)

Elec

trica

l Fie

ld(u

V/cm

)

Core-1Core-2Core-3

Ic Criterion (1uV/cm)

Conductor Shield

KSS 2008, July 9-11, 2008

0.001

0.01

0.1

1

100 1000 10000Loading Current (Arms, 60Hz)

AC

loss

(W/m

/pha

se)

Measured value

Low ac loss measured in 2G cable; mechanical & high voltage test requirements successfully passed• Cable - 2.5 meter single core• Current loading by go & return through conductor and shield• Ac loss measurement using lock-in amplifier with electrical 4 terminals

0.34 W/m/ph @ 800 ArmsAlmost same result as previous

1 meter test 2G cable

Bend Test (18D: Bending Dia. = 2.4 m)• No Ic degradation• No defect was found at

dismantling inspection

Voltage tests (Based on AEIC):• AC 69kV for 10 minutes, • Impulse ±200kV, 10 times

KSS 2008, July 9-11, 2008

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

Conductor: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

KSS 2008, July 9-11, 2008

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 High Field Insert Coil Showing Terminals, Overbanding and Partial Support Structure. Flange OD is 127 mm.

KSS 2008, July 9-11, 2008

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 T4.2 K Central field – self field

26.8 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

KSS 2008, July 9-11, 2008

Key metrics of 2G wire for broad market penetration

• Key metrics determining the price-performance characteristics of 2G HTS wire and qualifying for applications:

– Ic 500 A/cm at 0T & 77K– Ic(B) 100 A/cm at 1.5T &77K– L 1 km– V 1000 km/year

L (m)

Ic (A)

V (m/h)

KSS 2008, July 9-11, 2008

SuperPower’s 2G wire technology is based on high throughput processes

750Alumina + Yttria

360IBAD MgO

345Homo-epi MgO + LMO

180 (for ~ 1 μm HTS layer)MOCVD

Throughput of 4mm wide tape (m/h)Process

KSS 2008, July 9-11, 2008

Kilometer long tapes are routinely processed through IBAD MgO• High throughput established with IBAD enables 1000+m piece length processing

within hours!• Ion beam sputtering and assist condition stability must remain constant to obtain

uniformly good texture over 1000+m piece lengths.• On-line RHEED monitoring used to maintain texture uniformity over 1000+m

lengths

Over thirty 1,200 – 1400 m tapes have been successfully processed through IBAD MgO

1400 m long IBAD MgO

KSS 2008, July 9-11, 2008

Excellent in-plane alignment has been uniformly distributed on 1.3 km+ lengths

0123456789

10

0

200

400

600

800

1000

1200

Position (m)

FWH

M (d

egre

e)

FWHM of XRD phi scan at LMO (110)measured on one point in each meter

The FWHM values of the phi-scan at (110) of LMO, the cap layer of the 5-layer buffer stack, typically range from 6 to 8 degrees for the km+ lengths

Al2O3

Y2O3

IBAD MgO

Homo-epi MgO

30 nm LMO∆Φ = 6o-8o

0.2 m

KSS 2008, July 9-11, 2008

High critical currents in long lengths processed at high speeds

050

100150200250300350400

0 50 100 150 200

Position (m)

Crit

ical

cur

rent

(A/c

m-w

idth

)

measured every 5 m using continuous dc currents over the entire 12mm tape width at 77K with a criterion of 0.2 microvolt/cm. Ic_minimum = 314A/cm on 202m length

• Minimum Ic = 314 A/cm over 202 m• processed with MOCVD throughput of 90m/h• Uniformity over 202 m = 2.4%

KSS 2008, July 9-11, 2008

High critical currents in long lengths processed at high speeds

0

50

100

150

200

250

300

0 100 200 300 400 500 600

Position (m)

Criti

cal c

urre

nt (A

/cm

-wid

th)

measured every 5 m using continuous dc currents over the entire 12mm tape width at 77K with a criterion of 0.2 microvolt/cm.Ic_minimum = 221A/cm on 610m length

• Minimum Ic = 221 A/cm over 610 m• Processed with MOCVD throughput of 90m/h• Uniformity over 610 m = 2.65%

KSS 2008, July 9-11, 2008

High critical currents in long lengths processed at high speeds

0

50

100

150

200

250

300

0 200 400 600 800 1000

Position (m)

Criti

cal c

urre

nt (A

/cm

-wid

th)

measured every 5 m using continuous dc currents over the entire 12mm tape width at 77K with a criterion of 0.2 microvolt/cm. Ic_minimum = 170A/cm on 935m length

• Minimum Ic = 170 A/cm over 935 m• Processed with MOCVD throughput of 135m/h• Ic × L = 158,950m

KSS 2008, July 9-11, 2008

Capability of 320 A achieved in 4 mm widths

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 lengthIc = 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 )

KSS 2008, July 9-11, 2008

0

1

2

3

4

5

6

0 1 2 3 4 5

Thickness (μm)

Jc (M

A/cm

2 )

0.35 micron each pass

0.7 micron each pass

77K, 0T

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

Over 1 m length

Ic = 976 A = 813 A/cm3.33 μm, Jc = 2.44 MA/cm2

Ic=976A end-to-end of a 1m long 12mm wide tape

00.20.40.60.8

11.21.4

0 200 400 600 800 1000

Current (A)

Sign

al ( μ

V/cm

)

0100200300400500600700800900

0 1 2 3 4 5

Thichness (μm)

Ic (A

/cm

)

0.35 micron each pass

0.7 micron each pass

77K, 0T

High current wire processing is repeatable

KSS 2008, July 9-11, 2008

0

50

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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 SuperPower 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

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

0

20

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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 wire

KSS 2008, July 9-11, 2008

Mechanical properties of SuperPower 2G wire is far superior to RABiTS-based 2G wire

*Measurements Y. Zhou and K. Salama (U.Houston)

550 MPa1200 MPaHigh-strength 50 micron substrate

350 MPa650 MPa100 micron substrate

Critical tensile stress at RTYield strength at 77 K*2G wire made with

Conductor with 100 μm substrate

N. Cheggour, D. Van der Laan, J. Ekin (NIST)

Our 2G wire is 5 times stronger than competing 2G wire –can withstand high stress levels in operation

0

15

30

45

60

0 200 400 600Tensile Stress at R.T. (MPa)

Cri

tical

Cur

rent

(A)

100 micron substrateconductor 1100 micron substrateconductor 250 micron substrateconductor 150 micron substrateconductor 2

0

400

800

1200

1600

0 0.5 1 1.5 2

Tens

ile S

tress

(MP

a)

Tensile Strain (%)

T = 76K

Batch 1Batch 3 Batch 2

Complete Conductor (100 μm)

Bare substrates (50 μm)

Complete conductor (50 μm)

Bare substrates (100 μm)

0 5 10 15 20 25 30 35 40 450

200

400

600

800

1000

1200

1400

2G with 100μm substrate

2G with High-strength 50μm substrate

Stre

ss (M

Pa)

Strain (%)

KSS 2008, July 9-11, 2008

Excellent mechanical properties maintained even in 2G wire with 3 micron thick HTS films• Thick YBCO films will be needed to meet high current requirements.• To our knowledge, no other 2G wire manufacturer has published mechanical property data

on 2G wire with thick YBCO films

0

100

200

300

400

500

600

-13

Origina

lOrig

inal

50 37 33 24 19 18 16 13 12

Bend diameter (mm)

I c (A

/cm

-w)

4 mm wide 2G wire with 3 micron thick YBCO & 40 microns surround copper stabilizer

(data shown is average from 5 samples)

compression tension

95% Ic retention measured in axial tension & compression up to 0.5% even in tapes with 3 microns thick HTS layer

95% Ic retention measured in bending with YBCO in tension & compression down to a bend diameter of 13 mm even in tapes with 3 microns thick HTS layer

76 K

Measured by Danko van der Laan One

step

KSS 2008, July 9-11, 2008

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

KSS 2008, July 9-11, 2008

Summary

• Prototype applications including cable and high field coil with SuperPower’s 2G wire demonstrated the viability for commercialization.

• SuperPower’s 2G technology development is focused on three key metrics for a broad market penetration and improvement has been made on all areas.

– High throughput:• 750m/h for sputtering Al2O3+Y2O3 base layer• 360m/h for IBAD MgO template• 345m/h for sputtering Homo-epi MgO+LMO buffer• 180m/h for MOCVD REBCO

– High Ic:• 813A/cm-width at 77K and self-field over 1 meter length

– Long lengths:• 314A/cm-width over 202m• 221A/cm-width over 610m• 170A/cm-width over 935m

• Superior mechanical properties and in-field performance make 2G HTS wires suitable for high field and high stress applications

KSS 2008, July 9-11, 2008

Questions?

Thank you for your interest!

For further information about SuperPower, please visit us at: www.superpower-inc.comor e-mail: info@superpower-inc.com