Inline Monitoring and Process Control of REBCO Tape Production



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High Temperature Superconducting (HTS) Coated Conductors (CCs) based on epitaxial REBa2Cu3O7-δ (REBCO, RE = rare earth) thin films with superior mechanical properties and high current carrying capacity are being developed for various large-scale electric power and magnetic applications. The critical current density (Jc) of REBCO coated conductors in a magnetic field is higher than that of any other HTS. However, further Jc enhancement in REBCO coated conductors, particularly in magnetic fields perpendicular to the plane of the tape (B||c) is necessary due to the highly anisotropic nature of REBCO films. The inherently high in-field angular anisotropy of Jc of REBCO CCs can be diminished by introducing Artificial Pinning Centers (APCs) with optimal size, geometry, and density. The incorporation of a high BaMO3 (BMO; M=Zr, Hf, Sn) dopant concentration in REBCO films to achieve a higher density of nanoscale defects has been demonstrated via multiple routes of MOCVD processing as a very effective strategy to pin the vortices, especially in moderate-to-high applied magnetic fields and low temperatures. Manufacturing high quality REBCO tapes at scale with excellent homogeneous magnetic field performance pose a major challenge. Using XRD as an inline monitoring tool, it has been demonstrated that the quality of the tapes can be monitored in real time by tracking the lattice parameter of REBCO and secondary phase nanorod dimensions. In-field magnetic performance parameters measured using the Physical Property Measurement System (PPMS) and chemical compositional information obtained using Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) were correlated to the properties measured in real-time using XRD, which will play an instrumental role in ensuring chemical and physical homogeneity of the tapes when manufactured at scale. A custom gas cell with FTIR instrumentation has also been demonstrated as an excellent tool for tracking the chemical homogeneity of the vapor composition in real time and potentially being utilized for real time feedback control. The ICP – MS was also improved and standardized using novel techniques such as Continuous Calibration Verification (CCV) to monitor drift in the measurements and an Octopole Reaction System (ORS) was installed to remove potential interferences from polyatomic species generated in the plasma.



REBCO tape production