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 multifilamentDraw to align crystalsRoll to tapeFurnace heat treat
10 American Superconductor 55 filament (B2223) tape AMSC & SumitomoAMSC & Sumitomo have a reciprocal licensing agreementAmerican Superconductor 55 filament (B2223) tapeSumitomo (B2223) tape
11 AMSC B2223 Manufacturing Plant Larger billets, Process automation, Longer strands, Multi-dies, Faster line-speed, Combination of process stepsBegan volume production in early 2003Full capacity could be 20,000 km/year, now 900 km/year
12 (B2223) Critical Currents 2001-02 Manufacturing variability 3230> 150 m lengthsManufacturing Campaign for Detroit EdisonManufacturing Campaign for Customer X (2002)282624222018Frequency161412108642100103105108110113115118120123125128130133135138140143145148150End to End Critical Current, Amps170 A also demonstrated in short lengths
13 B2223 Wire Improvement Measured at AMSC & UW University of Wisconsin 21Measured at AMSC andUniversity of WisconsinMeasured at AMSC & UWUniversity of Wisconsin20191817Jc (A/cm2, 77 K, 0.1T, //c)1615141312199419951996199719981999200020012002Jc of 19.8kA/cm2 (77K, 0.1T, //c): a new level of performance for wire with production architectureMeasurement 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 K14 years: 900km/y plant fully operational15 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.m1000800Price/Performance Ratio, $/kA-m600World’s First HTS Wire Manufacturing Plant Opened By AMSC400200200 $/kA.m1995199619971998199920002001200220032004Reduced Manufacturing Costs ($/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 CablesIndustrial Magnetic ProcessingSignificant worldwide industry in B2223American Superconductor, Innova, Nordic Superconductor, Sumitomo Electric, Vacuumschmelze, TrithorBought and shut down by AMSC in 2002
19 Magnetic Field High magnetic field reduces current carrying capacity Lower temperatures enhance current carrying capacityB2223 must operate 20K – 40K for motors which have fields ~ 2TB2223 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/cm2Peter Lee’s Cosmic Plot (UW/ASC)101.6T1Power Apps30 – 77 K0.1Copper: up to 400 A/cm20.010.001
22 Key issues for power applications Overall current density Je of conductor, not just of superconductorPerformance in fieldMultiple filaments for AC applicationsAnisotropy of Jc with respect to field directionCost!Conductor itselfCooling (AC losses)Scalability of fabricationMechanicalStrength, bend radiusConductor shapetape or wireor new motor designs
23 Diboride & YBCOYBCO 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 geometryMassive lumps for new motor designs
26 Making Diboride tape Simple sintering ~700C Cu-sheathed tapetransverse cross sectionTube filling with MgB2 reacted powdersWire drawing and/or rollingFlat rollingLong lengths can be now fabricatedirregular cross sectionSimple sintering ~700C
27 + PIT Processing routes for the fabrication of MgB2 wires tube fillingBMgIN-SITUa)+MgB2EX-SITUb)draw to wiresimple sinteringreaction sintering23% porosity100m lengths of tapeIN-SITUEX-SITU
28 Powder in Tube Université de Genève Final Tape Flat rolling P.I.T. Ball milling under ArP. I. T.SwegeDrawFlat rollingFin= 5 mmFout= 8 mmF = 3.85 mmF = 2 mmTape 4 x 0.38 mm2P.I.T.Final TapeMgB2Flat rollingUniversité de Genève
29 HyperTech CTFF for MgB2CONTINUOUS TUBE FORMING AND FILLING (CTFF)
30 Irreversibility field L. Cowey et al., MgB2 + yttriaIncrease magnetic field capability by metallurgyCreate pinning defects by controlled alloying of MgB2
31 10-Meter Long Square MgB2 Wire Texas Center for Superconductivity and Advanced MaterialsUniversity of HoustonNASA Commercial Space CenterCSAMT10-Meter Long Square MgB2 Wire
32 Strain Effect on MgB2 long tape 100 h ball milled Strain gaugesModified Walters Spiral (WASP)MgB2 Taped=26 cmUniversité 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 onOuter 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 madeHyper 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 BSCCO250MgBpancake2BSCCO pancakeMgB22001504.2 KCritical Current [A]100503.03.54.04.55.0Magnetic Field [T]
37 Genoa 25 K Power Apps 30 – 77 K Peter Lee’s Cosmic Plot (UW/ASC) MA/cm2Peter Lee’s Cosmic Plot (UW/ASC)101Genoa25 KPower Apps30 – 77 K0.10.010.001
38 Magnesium Diboride (MgB2 ) AdvantagesNo weak-link effects, low anisotropyEasy to fabricate wires, films: <$10/kA.m potentialChallengesTc < 40 K (77 K applications like cables, transformers not viable)High field applications such as NMR not viablePossible applications in 20-30K range for modest field environments, e. g., rotating machinery
44 YBCO Coated Conductor tape Active programs in US, Japan and EuropeExamples of results in 2001:122 A (75 K) over 1 m by LANLWorld record for meter length50 A over 10 m by FujikuraWorld record for 10 meter lengthOver 60 m :FujikuraWorld’s longest processed tape
45 Comparative Development YBCO CCFujikura announces YSZ-IBAD process, early 1991Ten years later (2001):Fujikura produces 10 m with 50 A (77 K)B2223Work started in summer 1988Ten 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 lengthStability to over-currents or cracksAdequate current in MOD filmsMechanical properties – spalling, crackingStability of metal-oxide epitaxial interfaceDeposition rate for ion beam and laser processesThicker than 3 micron YBCO ?…but must have that 10 $/kA.m process!
48 Price/Performance $/kA.m 1200$/kA.m1000800Price/Performance Ratio, $/kA-m600World’s First HTS Wire Manufacturing Plant Opened By AMSC400200200 $/kA.m1995199619971998199920002001200220032004Reduced Manufacturing Costs ($/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 process1st October 2003First 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 plantbut all committed on pre-commercial processes!