A Method for Coating REBCO Superconductor Tape with a Thin Resistive Layer

Available for licensing is a simple, scalable oxidation process that improves industrial magnet design and performance.

Rare earth barium copper oxide (REBCO) is a high temperature superconductor. REBCO wire holds the promise of making very high field magnets which find commercial applications in nuclear magnetic resonance (NMR), the food and drug industry, as well as applications in large international research facilities such as particle accelerators.

Usually, magnet coils are made by winding insulated conductor wires. Due to the unique properties of REBCO wire, a coil made by insulated REBCO is prone to damage in magnet operation. Therefore, a no-insulation coil technology has been developed recently taking advantage of the fact that the resistive short circuit does not interfere the superconducting current path. Removing insulation results in very high efficiency and allows scientists and engineers to design extremely high field magnets that are exceptionally compact.

However, a coil with no insulation has the drawbacks of longer magnet charging times and a higher consumption rate of expensive cryogen, such as liquid helium. This is directly related to its low contact resistance (Rc) between adjacent turns in the coil made by commercial REBCO conductors. In order to mitigate the issues of no-insulation magnets, it is critically important to control turn-to-turn contact resistance.

Dr. Jun Lu at the National High Magnetic Field Laboratory has developed a process for oxidizing REBCO wire surface to achieve a controllable turn-to-turn contact resistance. With this technology, magnets can be charged quickly, and have low cryogen consumption. Meanwhile, it retains the advantage of the no-insulation coil technology which leads to very high magnetic field, coil self-protection and a very compact magnet design.