superior performance. powerful technology. Recent Developments in YBCO for High Field Magnet Applications D.W. Hazelton Principal Engineer, SuperPower, Inc. 2008 Low Temperature Superconductor Workshop November 11-13, 2008, Tallahassee, FL SuperPower, Inc. is a subsidiary of Royal Philips Electronics N.V.
2G HTS In-field performance improving with enhanced pinning In field performance vs. field angle drives coil design and performance Critical region for coil is 15 30 degrees Significant drop off in Ic Relatively large field component Angle measured relative to a, b plane (90 deg // c) Process parameter window being established for reproducible fabrication Critical current (A/cm-width) standard conductor performance others w/ enhanced pinning 180 160 140 120 100 80 60 40 20 0 77K, 1T 0.7 micron SmYBCO 0.7 micron GdYBCO 0.7 micron Zr:GdYBCO -20 0 20 40 60 80 100 120 Angle (degree) 1
New coils in 2008 with Zr-doped (Gd,Y)BCO 2G with improved in-field performance in LN2 2007 coil Coil ID (mm) clear 9.5 21 2008 coils Winding ID (mm) 19.1 28.6 2007 coil 2008 coil Wire Ic (A) 4 mm 72 82 a) 72 to 97 b) > 90 Winding OD (mm) Coil Height (mm) # of double pancakes 2G tape used (m) # of turns ~ 87 ~ 51.6 6 ~ 462 ~ 2772 ~ 87 ~ 56.7 6 ~ 480 ~ 2664 Coil Je (A/mm 2 ) per amp of operating current ~1.569 ~1.635 Coil constant (mt/a) ~ 44.4 ~ 41.9 2008 coil a 2
30% higher field achieved from 2G with improved in-field performance (2008a) Ic (A) for 4 mm wide wire 35 30 25 20 15 10 5 0 (Y,Sm)BCO wire 2007 coil (Y,Sm)BCO wire 2007 coil Zr:(Gd,Y)BCO wire for 2008 coil Zr:(Gd,Y)BCO wire for 2008 coil 75 K, 0.92 T (LANL) 77 K, 1 T (ORNL) -20 0 20 40 60 80 100 120 140 160 Angle between field and wire (degrees) Temperature Coil current Max Central Field (K) (A) (T) 77.4 22.7 0.95 70.25 44 1.84 65.8 54 2.26 64.5 57 2.39 63.8 58 2.43 Temperature 2008 a-coil with Zr-doped (Gd,Y)BCO 2007 coil with (Y,Sm)BCO Improvement 77 K 0.95 T 0.73 T 30% 65 K 2.39 T 4.2 K to be measured 9.8 T / 26.8 T* *in 19T background 3
Ic/Ic(0) SuperPower 2G HTS tolerates high axial stress up to 700 MPa 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Ic/Ic(0) Versus Stress at 77K Tape ID # M3-383-1-BS504-569M 0048 @ Peak Stress 0048 Unloaded 0115 @ Peak Stress 0115 Unloaded 0163 @ Peak Stress 0163 Unloaded Recommended Stress Limit 0 100 200 300 400 500 600 700 800 900 1000 Stress [MPa] Data from R. Holtz, NRL Ic drops by up to 10% reversibly under peak stress up to 700 MPa (about 0.6% strain) Above 700 MPa (0.6% strain) Ic degrades irreversibly N-value does not change with peak stress up to 700 MPa N-value degrades irreversibly coincident with irreversible Ic degradation Define σ IcRL (ε IcRL ) = Ic Reversiblity Limit = Peak monotonic stress (strain) for >98% reversibility of Ic Fatigue testing to 100,000 cycles shows no degradation up to 700 MPa (σ min /σ max = 0.1) 4
Universal model being developed to look at coil heating, quench initiation Universal Curve for 2G Conductor, H//c 1.0000 Temp (data set) 83K (8) 82K (1) 77K (1) 77K (4) 77K (5) 77K (7) 77K (9) 75K (6) 72K (1) 65K (1) 65K (9) 60K (8) 54K (8) 50K (1) 50K (2) 50K (4) 50K (7) 50K (9) 45K (1) 45K (9) 42K (8) 40K (2) 33K (9) 30K (2) 30K (4) 22K (9) 20K (2) 20K (7) 15K (2) 14K (9) 10K (2) 10K (7) 4.2K (3) 4.2K (6) 4.2K (9) 0.1000 Jc / Jco 0.0100 0.0010 Data Set 1: PB-208-2 Data Set 2: PB-208-2 Data Set 3: PB-208-2 Data Set 4: PB-208-2-11-3C Data Set 5: 1217 Data Set 6: PLee/LANL 1996 data Data Set 7: PB-208-2 Jc(θ) min Data Set 8: ONRL meas "std" cond Data Set 9: SP release 11/07 0.0001 0.001 0.01 0.1 1 H / H irr 5
Universal model being developed to look at coil heating, quench initiation Top = K 30 Ic(Bφ,T) / Ic(sf, 77K) 7 6 Ic(B,T) / Ic(sf,77K) 5 4 3 2 1.00 2.00 3.00 4.00 5.00 6.00 8.00 10.00 12.00 1 0-45 -30-15 0 15 30 45 60 75 90 105 120 135 150 165 180 195 210 225 field angle φ (deg) 6
Universal model being developed to look at coil heating, quench initiation Coil H2 - Iop / Ic Plot Ic (77, sf) = 80 A, Iop = 60 A, Top = 50 K Iop / Ic 0.000-0.100 0.100-0.200 0.200-0.300 0.300-0.400 0.400-0.500 0.500-0.600 0.600-0.700 0.700-0.800 0.800-0.900 0.900-1.000 21.205 21.180 21.155 21.130 21.105 21.080 21.055 21.030 21.005 20.980 20.955 20.930 radial position (cm) 20.905 20.880 20.855 20.830 20.805 20.780 60.185 60.608 61.032 61.455 61.878 62.302 62.725 63.148 63.572 63.995 64.418 64.842 65.265 65.688 66.112 66.535 66.958 67.382 67.805 68.228 68.652 69.075 2008 Low Temperature axial position Superconductivity (cm) Workshop 69.498 69.922 70.345 70.768 71.192 71.615 7
Universal model being developed to look at coil heating, quench initiation Coil H2 - Iop / Ic Plot Ic (77, sf) = 80 A, Iop = 60 A, Top = 60 K Iop / Ic 0.000-0.100 0.100-0.200 0.200-0.300 0.300-0.400 0.400-0.500 0.500-0.600 0.600-0.700 0.700-0.800 0.800-0.900 0.900-1.000 21.205 21.180 21.155 21.130 21.105 21.080 21.055 21.030 21.005 20.980 20.955 20.930 radial position (cm) 20.905 20.880 20.855 20.830 20.805 20.780 60.185 60.608 61.032 61.455 61.878 62.302 62.725 63.148 63.572 63.995 64.418 64.842 65.265 65.688 66.112 66.535 66.958 67.382 67.805 68.228 68.652 axial position (cm) 69.075 69.498 69.922 70.345 70.768 71.192 71.615 8
Questions? Thank you for your interest! For further information about SuperPower, please visit us at: www.superpower-inc.com or e-mail: info@superpower-inc.com 9
BACKUP 10
2G HTS has excellent performance over a wide field and temperature range I c /I c (77K, 0T) vs. Field (perpendicular - B//c) 10 4.2 K (Sample 1) 14 K (Sample 1) 22 K (Sample 1) 33 K (Sample 1) 45 K (Sample 2) 50 K (Sample 2) 65 K (Sample 2) 77 K (Sample 2) Ic (H//c)/Ic (77K 0T) 1 0.1 0.01 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 B (T) 11
High field insert coil demonstrated 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 9.5 mm (clear) Winding ID 19.1 mm Winding OD ~ 87 mm Coil Height ~ 51.6 mm # of Pancakes 12 (6 x double) 2G tape used ~ 462 m # of turns ~ 2772 Coil Je ~1.569 A/mm 2 per Coil constant A ~ 44.4 mt/a 12
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. 13
High field insert coil achieves record performance 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 72 A 82 A (77K, sf) 4.2 K Coil Ic - self field 221 A 30.0 25.0 19T background self field 26.8 T @ 175 A 4.2 K Amp Turns @ Ic- self field 612,612 4.2 K Je @ Ic, self field 346.7 A/mm 2 4.2K Peak Radial Field @ Ic, self field 3.2 T Central Field (T) 20.0 15.0 10.0 9.81 T @ 221 A 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) 9.81 T 175 A 485,100 5.0 0.0 0 50 100 150 200 250 Current (A) 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) 274.6 A/mm 2 2.7 T 26.8 T 14
2G HTS wire architecture 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 are: high strength, low ac loss (non-magnetic, high resistivity substrates) and high engineering current density (ultra-thin substrates) 2.66 A/mm 2 per A of operating current (current flows in a-b plane) c b a 15
SuperPower 2G HTS has superior mechanical strength 77K Yield Stress 970 MPa Strain at yield 0.92% Superpower 4mm Wide 2G-HTS Tape Stress-Strain Curves at Room Temperature and 77K Tape ID # M3-383-1-BS504-569M 1200 1100 1000 900 77K 800 Stress [MPa] 700 600 500 Room Temperature 0048.RT 0083.RT 0099.RT 400 0180.RT 300 0037.LN 200 0079.LN 100 0021.LN 0 0.0% 0.5% 1.0% 1.5% 2.0% Strain [%] Data from R. Holtz, NRL 16
Fatigue strength equivalent to Ic reversibility limit Fatigue-Life at 77K Superpower 2G Tape ID M-383-1-BS-505-569 Tension-Tension Cyclic Loading at Stress Ratio (min/max) = 0.1 Peak Stress [MPa] 1200 1100 1000 900 800 700 600 500 400 300 200 100 0 Ic drops below 98% Mechanical Failures Recommended Critical Stress for 100% Ic Retention Runouts Runouts are specimens that did not degrade either mechanically or electrically up to 100,000 cycles 0 1 10 100 Load Cycles 1,000 10,000 100,000 Data from R. Holtz, NRL 17
SuperPower 2G HTS wire has larger operating stress-strain window compared to other conductors 800 700 600 SP 2G HTS - High Je Stress (MPa) 500 400 300 "High Strength" 1G HTS - Moderate Je To 0.6%, 700 MPa 200 100 0 "Low Strength" 1G HTS - Moderate Je Nb 3 Sn - Moderate Je 0 0.1 0.2 0.3 0.4 0.5 Strain (%) 18