REBa2Cu3O7 (REBCO CC) coated conductors are a unique opportunity to achieve high currents at high magnetic fields where other materials cannot compete, especially in the emerging sectors for energy transition, including fusion, and high energy physics with high field magnets. Much effort has been devoted in recent years to increase yield, high-throughput, and overall decrease cost/performance ratio of REBCO CC manufacturing processes. We believe that our novel growth approach, entitled "Transient Liquid Assisted Growth (TLAG)” [1,2], which utilizes chemical solution deposition (CSD), can become a very competitive high-throughput and cost-effective fabrication method, because ultra-fast growth rates, beyond 1000 nm/s, are reachable by tuning the non-equilibrium transient liquid [3]. We have proven that TLAG has a wide working window compatible with the growth of nanocomposites and coated conductors with critical current densities of 3 MA/cm2 at 77K. Besides, very reproducible thick pyrolyzed layers showing nanocrystalline and very homogeneous microstructure can be fully decarbonated, at least up to 3 µm.
TLAG is a very non-equilibrium process where kinetic parameters have a strong influence on nucleation and growth, which implies that very solid and reproducible conditions are desired. Consequently, we developed a robust, facile and very reproducible colloidal ink [4] to control the supersaturation degree during growth, and we determined the correlation of the kinetic parameters of the process with epitaxy and growth rate. The use of fast acquisition in situ XRD imaging (<100 ms/frame) under synchrotron radiation, transmission electron microscopy, in situ resistivity experiments, and angular transport measurements have been crucial for this study.
In this presentation, I will discuss the current understanding of the TLAG process, relevant process parameters for growth of CC, and the relevance of the kinetic phase diagrams to guide us through the extreme non-equilibrium TLAG mechanisms [3]. Advances in growth rates, correlation between growth and properties, and richness of vortex pinning capabilities of films and nanocomposites will be discussed.
We acknowledge funding from EU-ERC_AdG-2014-669504 ULTRASUPERTAPE, EU-ERC-PoC-2020-IMPACT, EU-ERC-PoC-2022-SMS-INKS, CSIC-TRANSENER-PTI+, MICIN-SUPERENERTECH
[1] L. Soler et al, Nature Communications (2020)
[2] S. Rasi et al, J. Phys Chem C (2020)
[3] S. Rasi et al, Advance Science 2203834 (2022)
[4] L. Saltarelli et al, submitted
Keywords: Growth, critical current, REBCO, nanocomposite