2G HTS wires made on 30μm thick Hastelloy substrate

Abstract

REBCO (RE = rare earth) based high temperature superconducting (HTS) wires are now being utilized for the development of electric and electromagnetic devices for various industrial, scientific and medical applications. In the last several years, the increasing efforts in using the so-called second generation (2G) HTS wires for some of the applications require a further increase in their engineering current density (Je). The applications are those typically related to high magnetic fields where the higher Je of a REBCO wire, in addition to its higher irreversibility fields and higher mechanical strength, is already a major advantage over other superconducting wires. An effective way to increase the Je is to decrease the total thickness of a wire, for which using a thinner substrate becomes an obvious and attractive approach. By using our IBAD-MOCVD (ion beam assisted deposition-metal organic chemical vapor deposition) technology we have successfully made 2G HTS wires using a Hastelloy® C276 substrate that is only 30 μm in thickness. By using this thinner substrate instead of the typical 50 μm thick substrate and with a same critical current (Ic), the Je of a wire can be increased by 30% to 45% depending on the copper stabilizer thickness. In this paper, we report the fabrication and characterization of the 2G HTS wires made on the 30 μm thick Hastelloy® C276 substrate. It was shown that with the optimization in the processing protocol, the surface of the thinner Hastelloy® C276 substrate can be readily electropolished to the quality needed for the deposition of the buffer stack. Same in the architecture as that on the standard 50 μm thick substrate, the buffer stack made on the 30 μm thick substrate showed an in-plane texture with a Δϕ of around 6.7° in the LaMnO3 cap layer. Low-temperature in-field transport measurement results suggest that the wires on the thinner substrate had achieved equivalent superconducting performance, most importantly the Ic, as those on the 50 μm thick substrate. It is expected the 2G HTS wires made on the 30 μm thick Hastelloy® C276 substrate, the thinnest and with the highest Je to date, will greatly benefit such applications as high field magnets and high current cables.

J e (4.2 K, 31.2 T) beyond 1 kA/mm2 of a ~3.2 μm thick, 20 mol% Zr-added MOCVD REBCO coated conductor

“…This feature is ascribed to the degraded microstructure due to the extremely sensitivity of REBCO performance to the growth conditions. This situation is even worse with increasing Zr-addition, which limits the commercial REBCO coated conductors thickness at about ∼1.5 μm, and Zr addition below ∼10%, and makes the homogeneity a grand challenge for the large scale production of REBCO coated conductors 32 .…”

Hybrid superconducting fault current limiting CORC® wires with millisecond response time

“…One tape had an additional 5 μm of PbSn solder plating, and a 50 μm CuNi tape laminated (soldered) onto the REBCO side of the tape. Two CORC ® wires were designed using 2 mm wide REBCO tapes manufactured by SuperPower Inc. containing 30 μm thick Hastelloy substrates, also with 5 μm Cu plating [18]. The wire properties are summarized in table 1.…”

Two Level Undercut-Profile Substrate-Based Filamentary Coated Conductors Produced Using Metal Organic Chemical Vapor Deposition

“…The reference sample was produced using the standard etching procedure [14]. Following the 2LUPS fabrication, the buffer and superconducting GYBCO layers are deposited on the substrate in a commercial production system at SuperPower Inc. by means of IBAD-MOCVD [15]. The total thickness of the buffer layers is around 0.2 μm and the superconducting Gd1-xYxBa2Cu3O7 layer has a thickness of 1.1 μm.…”