Recent Advances in REBCO Coated Conductors via the RCE-DR process

Transcription

1 ALCA-JST International Workshop Mar. 7-9, Osaka, Japan Recent Advances in REBCO Coated Conductors via the RCE-DR process Sang-Im Yoo Department of Materials Science & Engineering & Research Institute of Advanced materials (RIAM),, Seoul , Korea

2 Collaborators Graduate Students in SNU () New Graduate Students: Mr. In-Sung Park Mr. Jae-Eun Kim Mr. Duho Lee Dr. Jung-Woo Lee Dr. Soon-Mi Choi Univ. of Wisconsin) (Samsung Display Co.) Mr. Tae-Hyun Seok (SK Hynix) Mr. Won-jae Oh Researchers in SuNAM (Superconductor, Nano & Advanced Materials) Co. Dr. Seung-Hyun Moon (CEO) Dr. Hunju Lee Dr. Jae-Hun Lee Researchers in KERI (Korea Electrotechnology Research Institute) Dr. Sang-Soo Oh Dr. Hong-Soo Ha

3 A New Coated Conductor Project in Korea Target Critical current; I C > 1,000 K, s.f. (length > 1 km, uniformity > 96%) In-field performance; I C > 1,000 K, 10 T Stacked conductor; I C > 1,800 K, s.f. I C measurement tech.; 0-10 T, > 1,800 A/cm, 20~77 K DC reactor demo; 400 mh, 1,500 A Budget US$13M; $9M from Gov t, $4M from SuNAM (June 2013 ~ May 2017, 4 years) Funded by Ministry of Trade, Industry & Energy (MOTIE), Korea through Inst. of Energy Tech. Evaluation and Planning (KETEP) Department of Materials Science & Engineering

4 Outline I. Introduction SuNAM : Superconductor, Nano & Advanced Materials ( 瑞藍 ) RCE-DR (Reactive Co-Evaporation Deposition & Reaction) II. Recent Advances in REBCO CC Optimization of conversion processing from an amorphous precursor to REBCO film on the basis of phase stability diagrams in low PO 2 Pinning improvement in GdBCO CCs by the RCE-DR process III. Summary

5 Production Facilities of SuNAM Co. Introduction Site area : 5,500 m 2, Building area : 1,750 m 2, Gross floor area : 3,050 m 2. Class < 10,000 clean room area : 1,000 m 2. Production capacity ~ 60 km/month(4 mm width) considering the yield(~ 70 %)

6 SuNAM HTS 2G Wire Architecture Introduction Ag REBCO LaMnO 3 Epi-MgO IBAD-MgO Y 2 O 3 Protecting layer (1.5 mm) Superconducting layer (1 ~ 3 μm) Buffer layer ~20 nm Homoepi-MgO layer ~ 20 nm IBAD-MgO layer ~ 10 nm Seed layer (Y 2 O 3 ) ~ 7 nm Diffusion barrier (Al 2 O 3 ) ~ 40 nm DC sputter RCE-DR Sputter IBAD (Sputter & E-beam) Al 2 O 3 Hastelloy or SUS Hastelloy C276 (Ni-alloy tape) or SUS-tape ( + Cu electroplating (+ lamination)) Electro-polishing

7 Introduction RCE-DR : Reactive Co-Evaporation Deposition & Reaction High rate deposition at low temperature & low oxygen pressure to a target thickness (> 1 μm) at once in the deposition zone (6 ~ 10 nm/s) Fast conversion by RCE-DR from an amorphous phase to superconductor at high temperature and relatively higher oxygen pressure in the reaction zone Simple, low system cost, easy to scale up (high deposition rate & large deposition area) <Throughput of each processing method 4mm width equivalent > MOCVD (Superpower) : ~ 180 m/h 1) PLD (Fujikura) : 20 m/h 2) MOD (AMSC) : ~ 100 m/h 3) RCE-DR (SuNAM) > 360 m/h 4) <Schematic of the RCE-DR process> 1) 2008 DOE Superconductivity Peer Review, Superpower, Inc. 2) 2009 RE123 Coated Conductors, Fujikura Annual reports 3) 2009 DOE Superconductivity Peer Review, AMSC Co. 4) 2010 ISS S.H. Moon (SuNAM) invited talk, 2011 MRS spring meeting S.I. Yoo (SNU) invited talk RCE DR : ~ 100 nm/sec or faster (SuNAM) PLD, MOCVD ~ 10 nm/sec, MOD ~ 1 nm/sec Department of Materials Science & Engineering

8 Recent report from SuNAM Introduction J.H. Lee et al., Supercond. Sci. Technol. 27 (2014)

9 Introduction SuNAM s CC on STS 310S by standard daily production 900 J c (77 K, 0T) > 4 MA/cm 2 I C (A/12mm) Length (m) Min Ic (A/cm-width) x L (m) > 0.5 Million A-m Production speed of 120 m/hr (12 mm width) with 1.4 mm thick film.

10 Introduction

11 SuNAM s 2G HTS Wire [ Specification Table ] Model AN CN LB/LS K Description Silver(+Cu ) Dry coating Copper Wet Coating Brass/ Stainless steel Lamination Polyimide tape(+) Insulation Substrate Hastelloy or Non-magnetic Stainless Steel Width [ mm ] Commercial : 4 mm, 12 mm. Special Order : 2 ~ 10 mm multi width is available Thickness [ mm ] HAS : 0.06~0.07 SS* : 0.11~0.12 HAS : 0.09~0.11 SS* : 0.14~0.16 HAS : 0.18~0.22 SS* : 0.23~ Final Process Silver Sputter Copper Plating Brass or SS* Lamination Wrapping Piece Length Above 100 m, 200 m, 300 m + without Splice Min. 77 k S.F. (100 ) / 150 / 200 A 4 mm (300 / 400) / 500 / 600 / 700 A 12 mm (From Dr. Moon, CEO of SuNAM)

12 Development of HTS 2G Wire Introduction Goal 800 Ic 77 K (2006.7) 100mx253A ( ) 270mx370A ( ) 540mx466A ( ) 500mx300A (2016 Target) 500mx400A ( ) 860mx600A (2011.2) 816mx572A 978mx579A ( ) I c x L : ( ) 997mx601A 700kAm 600kAm 500kAm 400kAm 300kAm (2009.8) 1065mx282A 200kAm 100kAm Length (m) 10kAm

13 II. Recent Advances in REBCO CC via RCE-DR Optimization of conversion processing from an amorphous precursor to REBCO film on the basis of phase stability diagrams in low PO 2 Pinning improvement in GdBCO CCs by the RCE-DR process

14 Motivation & Objectives Motivation A routine RCE-DR process of SuNAM should be improved for producing higher performance GdBCO CCs and also developed for other REBCO CCs. S.M. Choi et al., IEEE Trans. on Appl. Supercond. 23 (2013) um n m Objectives To achieve higher performance GdBCO CC through the optimization of RCE-DR processing Development of a new pinning site applicable to the RCE-DR process

15 Stability phase diagram of GdBCO J.W. Lee et al., J Alloy Compd., 602 (2014) log PO 2 (Torr) = ,880/T(K) [20 PO 2 100mTorr] log PO 2 (Torr) = ,150/T(K) [1 PO 2 10mTorr]

16 Growth mechanism of the GdBCO film by RCE-DR Gd Cu O Ba Cu Cu O Cu Gd O Gd Cu O Cu Ba O Cu Cu Ba Gd 2 O 3 GdBCO Cu-O Very low PO 2 zone (~ 10-5 Torr): Amorphous Film Lower PO 2 zone (~30 mtorr): Gd 2 O 3 + Liquid (< 5 sec) Higher PO 2 zone (~100 mtorr): GdBCO Film (< 1min) GdBCO growth mechanism: a seeded melt-textured growth!!! 500 nm

17 Control of conversion processing conditions Production rate 360 m(4 mm width) / h Processing routes for GdBCO CCs 150mTorr Precursor composition Gd : Ba : Cu 1 : 1 : /T (K) 880ºC 860ºC 840ºC

18 Magnetic field dependence of J c & Pinning force density (F p ) S.M. Choi et al., IEEE Trans. on Appl. Supercond J C (A/cm 2 ) o C, 77K 840 o C, 65K o C, 77K 860 o C, 65K o C, 77K 880 o C, 65K m 0 H (T) sample J c (MA/m 3 ) self-field 1T 3T 5T 840 C 860 C 880 C H // c 65K 77K 65K K X K K K Electronic Materials 77K & Devices 1.9 Laboratory X10-5 Pinning force density (GN/m 3 ) K 840 o C, 77K 840 o C, 65K 860 o C, 77K 860 o C, 65K 880 o C, 77K 880 o C, 65K m 0 H (T) 840 C 860 C 880 C sample 65K 77K 65K 77K 65K 77K F p,max = J c ⅹ B (GN/m 3 ) 8.8 (1.8T) 2.8 (0.4T) 7.1 (1.6T) 2.24 (0.35T) 4.2 (1.6T) 65K 1.3 (0.25T)

19 J c (MA/cm 2 ) Angular dependence of J c K, 1T H//ab 840 o C 860 o C 880 o C Angle (deg.) J c (MA/cm 2 ) S.M. Choi et al., IEEE Trans. on Appl. Supercond K, 3T 2.0 H//ab 840 o C 860 o C 880 o C Angle (deg.) The GdBCO CCs by RCE-DR show a sharp J c peak at θ = 90 (H//ab). A small broad peak of J c near θ = 180 (H//c) is also observed. The sample grown at 840 C shows higher J c values compared with those of samples grown at higher temperatures.

20 XRD θ-2θ scans and texture analysis of GdBCO CCs Intensity (Arb.unit) (003) Gd BaCuO 2 O 3 (222) 2 (004) (103) Gd 2 O 3 (400) CuO (-111) (005) MgO(200) Ni (111) (Cu K ) (006) Gd 2 O 3 (440) Ni (002) (007) Gd 2 O 3 (622) CuO(202) (008) S.M. Choi et al., IEEE Trans. on Appl. Supercond. (accepted) (deg.) (deg.) 880 o C (150mTorr) 860 o C (150mTorr) 840 o C (150mTorr) Temperature ( o C) Δ ( ) Δω ( ) 840 C C C The GdBCO (00l) reflections indicate that the GdBCO films are highly c-axis oriented. The second phases such as Gd 2 O 3 and CuO peaks are also observed in addition to the substrate peaks. A small GdBCO (103) peak is observed for the film prepared at 840 C, suggesting that a small amount of randomly oriented GdBCO grains exist in the film.

21 Cross-sectional TEM images 840 C 860 C 880 C S.M. Choi et al., IEEE Trans. on Appl. Supercond m 0. 2 m 0. 2 m The average particle sizes of Gd 2 O 3 are ± 42.6 nm in the 840 C sample, ± 53.1 nm in the 860 C sample, and ± 49.4 nm in the 880 C sample.

22 Polarized light microscope images 840 ºC sample S.M. Choi et al., IEEE Trans. on Appl. Supercon. (accepted) 20mm 20mm 20mm 20mm 20mm 20mm

23 EBSD analysis data of 840 C sample Image quality map S.M. Choi et al., IEEE Trans. on Appl. Supercon. (accepted) Inverse pole figure image 4μm Image quality map Inverse pole figure image 5μm

24 For the nominal composition of Gd:Ba:Cu = 1:1:2.5 Decreased intermediate PO 2 zone below 800 o C!!!

25 PM3 Zone 780 o C SEM micrographs of the surface morphology Normal process X 5k X 10k

26 PM3 Zone 780 o C TEM analysis 1 um 0.5 um Particle size (Gd 2 O 3 ) : ± 95.6 nm

27 PM3 Zone 780 o C EDX analysis

28 Increased pinning properties by composition control Driscoll et al., AIP Materials 2, (2014) ( ) Compositions studied here give a more Cu-rich liquid which influences growth kinetics and pinning (From Dr. Moon, CEO of SuNAM) There will be Gd 2 O 3 particles in all GdBCO samples but a specific precursor composition, PO 2, and T are key factors determining their performance. It is clear that very fine Gd 2 O 3 nanoparticles result in the highest performance.

29 In-field Performance (77 K) Driscoll et al., AIP Materials 2, (2014) RCE-DR GdBCO w/o APC (C,D composition) Only with composition control in RCE- DR process, we can achieve strong pinnings without APCs. (From Dr. Moon, CEO of SuNAM) SuNAM s present : 1.4 um (By Dr. Izumi, ISS2012(Japan))

30 Stability phase diagrams of REBCO (RE: Y, Gd, Sm) (a) T.B. Lindemer et al., Physica C 178 (1991) (b) J.L. MacManus-Driscoll et al., Physica C 241 (1995) (c) K. Iida et al., Supercond. Sci. Technol. 19 (2006) S478-S485. (d) J.W. Lee et al., J. Alloys Compd. 602, (2014) (e) C. Wende et al., J. Alloys Compd. 381 (2004) (f) J.H. Song, Master thesis, (2014) Department of Materials Science & Engineering

31 Comparison with previous reports on YBCO Equilibrium decomposition products of Y123: [20 PO mtorr] Y123 Y211 + Y132 + BaCu 2 O 2 (S) [100 PO mtorr] Y123 Y211 + Y132 + BaCu 2 O 2 (L) [1 PO mtorr] Y123 Y 2 O 3 + Y132 + L log PO 2 (Torr) = = ,783/T(K) [250 PO mtorr] Y123 Y211 + Y132 + L log PO 2 (Torr) = ,276/T(K)

32 II. Recent Advances in REBCO CC via RCE-DR Optimization of conversion processing from an amorphous precursor to REBCO film on the basis of phase stability diagrams in low PO 2 Pinning improvement in GdBCO CCs by the RCE-DR process Defect generation by the post-annealing process Defect generation by employing the dopants

33 Why post-annealing?

34 The post-annealing conditions 34 x 34

35 ρ-t curves & magnetic J c -B curves Resistivity (m cm) Resistivity (m cm) Temperature (K) Temperature (K) J.W. Lee et al. (submitted to IEEE Trans. on Appl. Supercond.) C in the PO 2 of 300 mtorr reference 5min 10min 30min 120min Holding time T c, zero (K) Ref min min min min 87.0 The T c, zero value of the sample annealed for 5 min is increased to ~ 94 K.

36 Magnetic J c -B curves J.W. Lee et al. (submitted to IEEE Trans. on Appl. Supercond.)

37 Angular dependence of J c & Microstructure analyses J.W. Lee et al. (submitted to IEEE Trans. on Appl. Supercond.) 77K, 1T 77K, 3T 1.0 B//ab Ref. After annealing B//ab Ref. After annealing J c (MA/cm 2 ) J c (MA/cm 2 ) Angle (deg.) Angle (deg.) Reference Post-annealed Post-annealed Post-annealed c-axis n m n m n m

38 II. Recent Advances in REBCO CC via RCE-DR Optimization of conversion processing from an amorphous precursor to REBCO film on the basis of phase stability diagrams in low PO 2 Pinning improvement in GdBCO CCs by the RCE-DR process Defect generation by the post-annealing process Defect generation by employing the dopants

39 BaSnO 3 addition wt% Sn doped 77 K, self-field I C (A/12mm) Length (m) (From SuNAM)

40 BaSnO 3 addition In-field performance wt% Sn doped GdBCO (I C,S.F. =547 A/12mm) 20 wt% Sn doped GdBCO (I C,S.F. =275 A/12mm) Undoped GdBCO (I C,S.F. =720 A/12mm) I C (A/12mm) K, 6300 G 0 B//ab B//c Angle (degree) (From SuNAM)

41 IV. Summary 41 The flux pinning properties of GdBCO CCs could be improved by controlling the conversion temperature of the amorphous precursor film from Gd 2 O 3 + liquid to the GdBCO phase due to the refinement of Gd 2 O 3 particles trapped in the GdBCO matrix. Both J c -B curves and the angular dependence of J c of GdBCO CCs reveal that the flux pinning can be improved by the post-annealing process and also by the dopant like Sn. Further R&D is under progress to develop higher performance REBCO CCs exceeding GdBCO, which include Y or other RE elements and their binary or ternary mixture, in addition to a strong effort to improve the pinning properties of GdBCO CC. Our group started R&D on a multicore REBCO tape similar to the BiSCCO tape (Industry Fund from POSCO). 41

42 Thank you very much for your kind attention