2G HTS Wire
Processing steps include:
Electropolishing to achieve the smooth, clean surface for the 12 mm wide hastelloy-based substrate, as a prerequisite for the successful addition of the buffer and superconductor layers
Ion beam assisted deposition (IBAD) or sputtering of a stack of buffer layers that act as a template layer to introduce the biaxial texture for the superconductor material
Metal organic chemical vapor deposition (MOCVD) of the superconductor, based on yttrium barium copper oxide (YBCO) or other rare earth materials
Sputtering of a thin cover layer of silver to provide electrical contact
Slitting to application-specific tape widths (i.e. 6 mm, 4 mm)
Depending on the application, electroplating to completely surround the wire (Surround Copper Stabilizer, or SCS).
For additional product information, see 2G HTS Wire > [English], [Japanese], or [Chinese]
Configuration of SuperPower® 2G HTS Wire
Attributes | Manufacturing Capability | Wire Applications & Capabilities
SuperPower routinely manufactures long lengths (kilometer-class) of robust and high performing 2G HTS wire (coated conductors), based on (RE)BCO (rare earth barium copper oxide elements), with variations in width, substrate thickness, silver and copper stabilizer thickness, plus optional insulation. This 2G HTS wire is fabricated by an automated, continuous process using thin film deposition techniques, such as those used in the semiconductor industry, to apply the superconducting material on buffered metal substrates.
Attributes of SuperPower® 2G HTS Wire
- SuperPower 2G HTS Wire demonstrates superior performance in a magnetic field due to the nano-scale flux pinning centers created through the use of a rare earth element substitution in the materials. The nano-scale flux pinning takes any magnetic flux that may be moving through the wire and fixes it into place. This is done to decrease the amount of resistance. It is easier for the current to move around a stationary object than around one that is moving.
- SuperPower 2G HTS Wire is half as thick as 1G HTS wire and 2G HTS wire made by other companies
- total wire thickness is only 0.095 mm, twice the engineering current density
- SuperPower 2G HTS Wire uses Surround Copper Stabilizer (SCS)
- no sharp corners, valuable for high voltage applications
- can be easily soldered for joints
- SuperPower 2G HTS Wire uses high-strength Hastelloy® substrate
- better mechanical properties and lower ac losses
- non-magnetic substrate has lower ferromagnetic losses
- highly-resistive substrate results in less eddy current losses
- SuperPower 2G HTS Wire is very mechanically robust
- can be slit to narrow widths
- capable of small twist pitches (important for striated geometry to be fully effective in long lengths)
- critical stress for Ic degradation up to 700 MPa (depends on Cu fractions)
- SuperPower 2G HTS Wire has excellent in-field performance in magnetic fields at intermediate and low temperatures
- 480 A/cm at 4.2K, 10 T, field perpendicular to wire
- 540 A/cm at 40K, 3 T, field perpendicular to wire
SuperPower is able to deliver large volumes of long-length, high performance 2G HTS wire:
- Routinely manufacturing long single-piece lengths
- 100-300 m typical shipped lengths
- helix processing (as opposed to wide tape) enables long piece lengths even for same throughput
- Achieving high critical current in long lengths: 100A standard; 110 – 140+ A premium in 4 mm widths
- Achieving very uniform critical current of about 10% standard deviation over long lengths
- Longer lengths available with splices
- Excellent results with joints, splices and soldering
- no degradation in Ic even when joint/splice is bent over 1" diameter and thermal cycled
- typical joint resistance less than 20 nΩ, 100 mm over lap
- no problems with soldering to SuperPower 2G HTS Wire
Wire Applications & Capabilities
This wire has the potential to operate devices at liquid nitrogen temperatures. At 77K, REBCO can operate up to ~1 T maximum field.
SuperPower 2G HTS Wire is customized to meet unique requirements of multiple applications:
- excellent 2D uniformity of critical current across width for ROEBEL cables
- tight bandwidth of critical current for FCL
- rounded edges of the SCS (surround copper stabilizer) wire is excellent for high voltage applications
- lightweight wire, important for rotating machinery
- same level of high-field coil performance can be achieved with Zr-doped wire with less zero-field 77 K Ic, less wire and larger bore
- applications that involve magnetic field benefit from the additional improvement factor of in-field Ic retention
- fields in a toroidal SMES are mainly axial (//a,b), maximizing the use of 2G HTS
- 2G HTS enables high field operation for compact, high energy density systems
- HTS improves power quality, enabling faster switching speeds in motors and generators
... the mark of excellence
The world’s first prototypes of cables, FCL, high field magnets and coils have been successfully constructed and tested by our partners using SuperPower 2G HTS Wire. Some examples:
- Utilizing SuperPower’s 2G HTS wire, Advanced Conductor Technologies LLC constructed a CORC (conductor on round core) cable consisting of 20 superconducting tapes, wound into 6 layers, forming a cable with an outer diameter of 7 mm and then was wound into a 2 layer, 12 turn magnet with an inner diameter of only 9 cm. The CORC cable HTS magnet reached a winding current of 1950 A at 20 T, making it the first layer-wound magnet in which the winding current exceeded 1000 A.
- In 2012, the world's first multi-layer electromagnet constructed by the National High Magnetic Field Laboratory, the University of Colorado, and the National Institute of Standards and Technology, wound from an HTS cable at a field of 20.0 tesla, was successfully demonstrated
- also demonstrated a record winding current of 4,100 amperes in a single-turn magnet at a background field of 19.81 tesla
- Nexans SuperConductors GmbH of Huerth, Germany in 2012 selected SuperPower’s 2G HTS wire for the world’s first resistive superconducting fault current limiter (SFCL) based on 2G HTS materials (ECCOFLOW Project)
- 2G wires reduce the already low losses in the conductor material by around 90%, thereby lowering operating costs and also providing an even faster response to a short circuit
- Oswald Elektromotoren GmbH of Miltenberg, Germany is using SuperPower 2G HTS wire in a number of superconducting motor projects.
- A world’s first in 2011, fusion research company Tokamak Solutions worked with partners at Oxford Instruments, the Czech Technical University and Institute of Plasma Physics, Prague to use HTS magnets on a tokamak
- In 2011, a research team at the National High Magnetic Field Laboratory (NHMFL) at Florida State University reached a new world record in magnetic field generation, successfully testing a superconducting electromagnet to a field of 35.4 Tesla.
- A 30 meter 2G HTS cable was constructed by Sumitomo Electric Industries using SuperPower® 2G HTS Wire and installed in the National Grid System in 2008 as part of the Albany HTS Cable Demonstration. AC losses of 0.36 W/kA-m were demonstrated.
- General Cable Superconductor and Karlsruhe Institute of Technology have qualified SuperPower 2G HTS Wire for use in their Roebel cables.
Additional information about SuperPower 2G HTS Wire: