Bruker HTS Coated Conductors

Magnet technology and electric engineering require increasing quantities of quality assured and commercially processable HTS wire. Bruker EST addresses this demａnd with an industrial scale production of second generation YBCO-based coated conductors for application at a temperature range between 4 Kelvin and 77 Kelvin.

Tape architecture: designed for high performance

HTS coated conductors by Bruker display a multilayer architecture: stainless steel tape material of 100µm thickness serves as a substrate, or carrier, for a 1.5 micrometer (µm) buffer layer of yttria-stabilized zirconia oxide (YSZ) and a 0.05 µm buffer layer of ceramic cerium (IV) oxide (CeO2). The buffers provide both a chemical barrier and a textured surface for the deposition of a 1 µm superconducting layer of high-quality bi-epitaxial yttrium barium copper oxide (YBCO). A protecting and stabilizing 0.2 µm layer of gold or silver covers the superconducting film. The layer architecture as a whole is subsequently encased by a 20 µm copper plating serving as a shunt.

Production process: industrial quality assurance, output, and speed

In view of expanding commercial markets, HTS production at Bruker EST is based on physical deposition processes. The production technology affords uniform quality characterized by high critical currents and favorable mechanical properties of the conductor material as well as cost efficiency at high yields and throughput rates: Polished stainless steel substrate tape is cleaned before the YSZ buffer is applied by alternating beam assisted deposition (ABAD). Subsequently the CeO2 buffer and the superconducting polycrystalline YBCO layer are added by high-resolution pulsed laser deposition (HR-PLD). Applying the gold or silver film by physical vapor deposition (PVD) finalizes the layer architecture on the substrate which is then annealed and galvanic copper-plated. Dependable for commercial application

With its proprietary HTS production process, Bruker has mastered one of the most demanding barriers to superconductor application of a wide scope: YBCO, the brittle oxide ceramic superconductor, is fashioned into tape wire material with high critical currents which can be handled and processed in industrial environments. Stainless steel tape as a substrate provides excellent mechanic characteristics which the production process successfully transfers to the entire conductor. HTS coated conductors by Bruker EST feature a maximum tensile strength of 650 MPa and a minimum bending radius of 6 millimeters.