2G HTS High Field Magnet Demonstration - SuperPower Inc.

2G HTS High Field Magnet
Demonstration
Presented by: Drew W. Hazelton
SuperPower, Inc.
Magnet Technology Conference, MT-20
August 28, 2007
Providing HTS Solutions for a New Dimension in Power – TODAY!

Acknowledgements
SuperPower, , Inc.
• Jason Duval, Venkat Selvamanickam, Yi-Yuan Xie
• …and 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 / FSU
• Zhijun Chen, David Larbalestier, Denis Markiewicz, Ed Miller, Patrick Noyes,
Ken Pickard, Ulf Trociewitz, and Huub Weijers
• A portion of this work was performed at the National High Magnetic Field
Laboratory, which is supported by NSF Cooperative Agreement No. DMR-
0084173, by the State of Florida, and by the DOE
MT-20 August 28, 2007 –1–

SuperPower’s 2G wire utilizes high strength substrates
coupled with high throughput processing
SuperPower’s 2G HTS wire is based on high throughput IBAD MgO and
MOCVD processes.
Use of IBAD as buffer template provides us choice of any substrate.
• Advantages of IBAD are 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 and to minimize capital
investment.
20μm Cu
2 μm Ag
1 μm HTS
~ 30 nm LMO
~ 30 nm Homo-epi MgO
~ 10 nm IBAD MgO
< 0.1 mm
50μm Hastelloy substrate
20μm Cu
MT-20 August 28, 2007 –2–

Long length processing of 2G wire demonstrated
250
Critical current
(A/cm)
200
150
100
50
0
Jan. 2007
0
50
100
150
200
250
300
350
400
450
500
550
600
77 K, Ic measured every 5 m using continuous dc
currents over entire tape width of 12 mm (not slit)
Position (m)
Minimum Ic = 173 A/cm over 595 m
Ic × Length = 102,935 A-m
Uniformity over 595 m = 6.4%
Process
(single pass)
IBAD MgO
Homo-epi MgO
LMO
MOCVD
Speed of 4 mm tape
(m/h)
360
213
360
135
MT-20 August 28, 2007 –3–

Critical current properties of the 2G wire make it ideal for
lower temperature, high field applications
Data (solid figures) taken on bridge sample.
Dashed red line is hypothetical curve.
J c
( MA/cm 2 )
45
40
35
30
25
20
15
10
5
4.2K//c
4.2K//ab
0
0 5 10 15 20 25 30 35
μ 0
H (Tesla)
J e
( A/mm 2 )
10000
8000
6000
4000
2000
0
0 3 6 9 12 15 18 21 24 27 30 33
μ 0
H (Tesla)
4.2K//c
4.2K//ab
Superconductor critical current density
Data by Z. Chen at NHMFL / FSU (2007)
Conductor critical current density
thickness ~ 95 μm
MT-20 August 28, 2007 –4–

Mechanical properties of 2G wire are ideal for high stress
applications
Stress-strain traces for SuperPower 2G YBCO at 76K. Included are a
trace of the base substrate material, Hastelloy C276 which dominates the
conductor mechanical properties. Note the impact of copper stabilizer
which slightly lowers the overall composite strength.
Measurements conducted at NIST by Ekin et al (2004)
MT-20 August 28, 2007 –5–

50 micron substrate tape shows superior bend strain
characteristics
Ic/Ic(original)
100%
90%
80%
70%
60%
50%
Bend at R.T. and Test While held on Mandrel
100 micron substrate
4 mm wide with 20
micron surround Cu
50 micron substrate
4 mm wide and
surround Cu
50 micron substrate
12 mm wide no Cu
-10 -11 -12 -14 -16 -19 -23 24 19 16 14 12 10 9
Compressive
Bend diameter (mm)
Tensile
95%
Maximum Bend Strain = +/- t / D ~ 95 μm / 11000 μm = 0.86 % (~ 0.45 % on the YBCO)
MT-20 August 28, 2007 –6–

High field insert coil construction
Conductor:
Dimensions: 4 mm wide x
95 microns thick
Substrate: 50 micron Hastelloy
HTS:
~ 1 micron YBCO
Stabilizer: ~ 2 micron Ag on YBCO
Tape Ic
Coil Winding
~ 20 microns of surround
copper stabilizer per side
72 – 82 A, 77 K, sf
Double Pancake Construction
Dry Wound (no epoxy)
Kapton polyimide insulation (cowound)
Overbanding: 316 Stainless Steel
Coil ID
Winding ID
Winding OD
Coil Height
# of Pancakes
2G tape used
# of turns
Coil Je
Coil constant
9.5 mm (clear)
19.1 mm
~ 87 mm
~ 51.6 mm
12 (6 x double)
~ 462 m
~ 2772
~1.569 A/mm 2 per A
~ 44.4 mT/A
MT-20 August 28, 2007 –7–

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.
MT-20 August 28, 2007 –8–

Test setup at NHMFL
Data Acquisition
HTS magnet
power supply
Shunt
Fault
detection
1.5 Ω Dump
resistor
Insert & Hall data
YBCO insert
Large Bore
Resistive magnet
Hall sensor
MT-20 August 28, 2007 –9–

Typical V-I trace (19T background field)
1.00E+00
lead-lead voltage in 19 T background
lead-lead
Pancake 12
1.00E-01
1.00E-02
Ic = 175 A
inductive voltage @ 5.9
A/min
Voltage [V]
1.00E-03
1.00E-04
1.00E-05
inductive voltage @ 3.7 A/min
1.00E-06
1.00E-07
1 10 100 1000
Current
MT-20 August 28, 2007 –10–

Hall probe data shows linear field generation
Hall probe signal showing non-linearity of sensor and near-perfect field generation by insert
30
0.20
28
Hall
linear fit, 44.4 mT/A
deviation from linear
0.15
26
0.10
Central Field [T] .
24
22
current reversal loop
0.05
0.00
non-linearity [T] .
20
pause in ramping
-0.05
19 T Axial
Background Field
18
0 50 100 150 200 250
Insert current [A]
-0.10
MT-20 August 28, 2007 –11–

High field insert coil achieves world records for highest
HTS field, highest magnetic field by a SC magnet
Peak hoop stress ~ 215 MPa,
well below tape limit
Ic of Tapes in Coil
4.2 K Coil Ic - self field
72 A – 82 A
(77K, sf)
221 A
19T background
self field
4.2 K Amp Turns @ Icself
field
612,612
30.0
4.2 K Je @ Ic, self field
346.7 A/mm 2
Central Field (T)
25.0
20.0
15.0
10.0
5.0
0.0
26.8 T @ 175 A
9.81 T @ 221 A
0 50 100 150 200 250
Current (A)
4.2K Peak Radial Field
@ Ic, self field
4.2 K Central field –
self field
4.2 K Coil Ic – 19 T
background (axial)
4.2 K Amp Turns @ Ic –
19 T background (axial)
4.2 K Je @ Ic, 19 T
background (axial)
4.2 K Peak Radial Field
@ Ic, 19 T bkgd (axial)
4.2K Central Field – 19
T background (axial)
3.2 T
9.81 T
175 A
485,100
274.6 A/mm 2
2.7 T
26.8 T
MT-20 August 28, 2007 –12–

Summary
• We have not reached the limit of 2G HTS wire capability
• Coil performance limited by operation of Pancake 12
• Stress limit on the wire still has significant margin
Hoop stress ~ 215 MPa vs. ~ 600 MPa limit
• 2G HTS wire with 50 micron Hastelloy substrate enables high
winding pack Je
• 2G HTS wire is available in lengths and quantity to enable
development in high field magnet design and construction
• 30 T (and beyond) is within our grasp……
MT-20 August 28, 2007 –13–

Questions?
Thank you for your interest!
For further information about SuperPower and to see the coil,
please visit us at Booth No. 5
or at:
www.superpower-inc.com
or e-mail: info@superpower-inc.com
MT-20 August 28, 2007 –14–