Progress in second-generation HTS wire development and manufacturing

doi:10.1016/j.physc.2008.05.063

Physica C: Superconductivity

Volume 468, Issues 15–20, 15 September 2008, Pages 1504-1509

https://doi.org/10.1016/j.physc.2008.05.063 Get rights and content

Abstract

2007 has marked yet another year of continued rapid progress in developing and manufacturing high-performance, long-length second-generation (2G) HTS wires at high speeds. Using ion beam assisted deposition (IBAD) MgO and associated buffer sputtering processes, SuperPower has now exceeded piece lengths of 1000 m of fully buffered tape reproducibly with excellent in-plane texture of 6–7 degrees and uniformity of about 2%. These kilometer lengths are produced at high speeds of about 350 m/h of 4 mm wide tape. In combination with metal organic chemical vapor deposition (MOCVD), 2G wires up to single piece lengths to 790 m with a minimum critical current value of 190 A/cm corresponding to a Critical current × Length performance of 150,100 Am have been achieved. Tape speeds up to 180 m/h have been reached MOCVD while maintaining critical currents above 200 A/cm in 100+ m lengths. Thick film MOCVD technology has been transitioned to Pilot manufacturing system where a minimum critical current of 320 A/cm has been demonstrated over a length of 155 m processed at a speed of 70 m/h in 4 mm width. Finally, nearly 10,000 m of 2G wire has been produced, exhaustively tested, and delivered to the Albany Cable project. The average minimum critical current of the wire delivered in 225 segments of 43–44 m is 70 A in 4 mm widths. A 30 m cable has been fabricated with this wire by Sumitomo Electric and has been installed in the power grid of National Grid in downtown Albany and is the world’s first 2G device installed in the grid.

Introduction

Progress in scale up of second-generation (2G) high temperature superconductors (HTS) has been happening at a rapid pace in the last three years [1], [2], [3]. Critical current of 300 A/cm has been recently reported in a 368 m long tape produced by ion beam assisted deposition (IBAD) and pulsed laser deposition (PLD) process [3]. Tape lengths more than 400 m with critical currents (I_c) of about 200 A/cm have been produced at a high linear tape speed of 135 m/h of 4 mm wide tape [2]. In this case, high tape speed has been enabled by employing a combination of high-rate processes in all steps. High-rate processing has been achieved at SuperPower using IBAD MgO-based biaxially-textured templates [4] and metal organic chemical vapor deposition (MOCVD) for the HTS layer [5]. SuperPower had established Pilot-scale manufacturing of 2G HTS, which became fully operational in 2006 [6]. Since then, our program has been focused on achieving key metrics to improve the cost-performance characteristics of 2G wire. The key metrics that have been addressed are high currents, high throughput, and long lengths. Further, SuperPower has been working to demonstrate the availability of large quantities of 2G wire for prototype projects, in particular for the Albany Cable project. In this paper, we report progress in 2007 in the 2G wire program at SuperPower specifically focusing on achieving key metrics as well as delivery of 2G wire for the Albany Cable project.

Section snippets

2G Wire delivery for the albany cable project

The Albany Cable project was successfully commissioned in July 2006 with a 350 m cable made with 1G wire and installed in the power grid of National Grid in downtown Albany [7]. The next step was to replace 30 m of the 1G cable section with an equal length of 3-phase, fully shielded 2G cable. The delivery requirements of 2G wire for the Albany Cable project were primarily 225 segments in 43 m piece lengths with a critical current value of 100 A/cm at 77 K for a total of 9700 m. Previously, we had

High critical currents

In 2006, we reported a critical current value of 721 A/cm measured over entire tape width of 12 mm in a 3.5 μm thick MOCVD film produced in five passes on IBAD MgO buffered tape [2], which corresponds to a critical current density of 2.06 MA/cm². Microstructural examination of thick films at various stages of processing (i.e.) after each pass, indicated that a-axis grain growth as well as compositional inhomogeneity increased with increasing film thickness. Hence in 2007, we focused on modifying

High throughput

In 2006, we reported that the throughput of the IBAD MgO process was increased to 360 m/h of 4 mm wide tape [2]. In 2007, we were able to achieve higher tape speeds in our buffer deposition processes atop IBAD MgO. In cases of both homo-epi MgO and LMO buffers, we increased tape speed by employing 11 tape wraps in the helix tape handling system compared with 6 wraps last year. Hence, we were able to increase the homo-epi MgO and LMO process speeds to 345 m/h of 4 mm wide tape.

In 2006, we reported

Long lengths

A third and important metric to achieve low-cost 2G wire is the ability to produce long single piece lengths with good critical current. In 2006, we had demonstrated piece lengths up to 427 m with a minimum critical current of 191 A/cm which corresponds to a I_c × Length performance of 81,550 A m [2]. In January 2007, we successfully produced a 595 m long 2G wire at high tape speeds of 360 m/h for IBAD MgO, 213 m/h for homo-epi MgO, 360 m/h for LMO, and 135 m/h in MOCVD of HTS layer, all values

Conclusions

Significant progress continues to be made against all metrics towards the goal of producing low-cost 2G wire. Critical current of 740 A/cm has been achieved in 2.8 μm thick films corresponding to a J_c of 2.65 MA/cm². The thick film MOCVD process has been transitioned to our Pilot MOCVD system where a minimum critical current of 320 A/cm was achieved over 155 m at a tape speed of 70 m/h of 4 mm wide tape. Tape speeds in the IBAD MgO, homo-epi MgO and LMO processes have been increased to about 350 m/h of

Acknowledgments

This work was partially supported by the Title III office, US Department of Energy, Air Force Research Laboratory and the Air Force Office of Scientific Research. Part of the work was also done in a Cooperative Research and Development Agreements with Los Alamos National Laboratory, and Oak Ridge National Laboratory.

References (7)

V. Selvamanickam et al.
Physica C
(2007)
Y. Yamada et al.
Supercond. Sci. Technol.
(2004)
T. Izumi, Presented at European Conf. Appl. Supercond. Brussels, Aug. 13–17,...

There are more references available in the full text version of this article.

Cited by (69)

Engineering REBCO high temperature superconductor materials for applications
2023, Physica C: Superconductivity and its Applications
MOCVD-derived GdYBCO tapes with smooth surface and low R<inf>s</inf> based on a new self-heating technology
2018, Ceramics International
Citation Excerpt :
REBa2Cu3O7-δ ((REBCO), RE = rare earth element) high temperature superconducting (HTS) tapes [1–5], which are also called coated conductors, have significant prospects for electric power applications, such as superconducting cable, magnetic resonance imaging, superconducting magnetic energy storage, strong magnet, superconducting generator, superconducting motor, superconducting current limiter and transformer [6–11].
The metal organic chemical vapor deposition (MOCVD) method was used to prepare GdYBCO films on LaMnO₃/ homo epitaxial-MgO/ ion-beam-assisted-deposition-MgO/ solution-deposition-planarization-Y₂O₃ buffered Hastelloy tapes. By adopting a simple self-heating technique, the substrates were heated by the joule effect after applying a heating current (I_h) through Hastelloy metal tapes. The effects of substrate temperature and (Gd, Y)/Ba ratio (r_c) in the precursor on the biaxial texture, surface morphology and superconducting performance of GdYBCO films were systematically investigated by varying the values of I_h and r_c. Needle-like outgrowths formed on the substrate surface were characterized using a scanning electron microscope, energy dispersive spectrometer and X-ray diffraction system. The results show that a high I_h or r_c leads to the formation of needle-like outgrowths. Therefore, I_h and r_c are crucial process parameters that control the growth of needle-like outgrowths on the surface of GdYBCO films. Three hundred nanometer thick GdYBCO films were prepared at different I_h and r_c by the MOCVD process. At an I_h of 27.0 A and an r_c of 0.6, the surface of the GdYBCO film was very smooth and dense, which can provide a good template for multiple depositions of GdYBCO films. The critical current density of the deposited 300 nm-thick GdYBCO film was 4.4 MA/cm² (77 K, 0 T), which is attributed to good biaxial texture and appropriate film composition. Furthermore, the microwave surface resistance (77 K, 10 GHz) of the GdYBCO film was merely 0.581 mΩ.
Topography evolution of rough-surface metallic substrates by solution deposition planarization method
2018, Applied Surface Science
Citation Excerpt :
However, it is found that interface properties, such as surface roughness and materials composition on the substrates have a great influence on the texture formation of the IBAD-MgO film [8]. To date, many surface planarization techniques have been developed to improve flatness on the substrate surface, including mechanical polishing [9], electro-polishing [10], chemical mechanical polishing [11] and solution deposition planarization (SDP) [12]. In contrast to other techniques based on removing bulge materials from the substrate surface, the SDP process is to add oxide layers on substrate surface by solution coating.
As an emerging technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention on the fabrication of the second generation high temperature superconducting (2G-HTS) tapes. In our work, a number of amorphous oxide layers were deposited on electro-polished or mirror-rolled metallic substrates by chemical solution route. Topography evolution of surface defects on these two types of metallic substrates was thoroughly investigated by atomic force microscopy (AFM). It was showed that root mean square roughness values (at 50 × 50 μm² scanning scale) on both rough substrates reduced to ∼5 nm after coating with SDP-layer. The smoothing effect was mainly attributed to decrease of the depth at grain boundary grooving on the electro-polished metallic substrate. On the mirror-rolled metallic substrates, the amplitude and frequency of the height fluctuation perpendicular to the rolling direction were gradually reduced as depositing more numbers of SDP-layer. A high J_c value of 4.17 MA cm⁻² (at 77 K, s.f.) was achieved on a full stack of YBCO/CeO₂/IBAD-MgO/SDP-layer/C276 sample. This study enhanced understanding of the topography evolution on the surface defects covered by the SDP-layer, and demonstrated a low-cost route for fabricating IBAD-MgO based YBCO templates with a simplified architecture.
Development of metal-organic deposition-derived second-generation high-temperature superconductor tapes and artificial flux pinning
2023, Advances in Manufacturing
Quench Behaviors of REBCO-Coated Conductors Impregnated with Aluminum Nitride–Filled Epoxy Composites
2023, Journal of Superconductivity and Novel Magnetism
Advances in second-generation high-temperature superconducting tapes and their applications in high-field magnets
2022, Soft Science

View all citing articles on Scopus

View full text