Scale Up of High-Performance REBCO Tapes in a Pilot-Scale Advanced MOCVD Tool With In-Line 2D-XRD System
We have reported the development of an Advanced Metal-Organic Chemical Vapor Deposition (A-MOCVD) method featuring ohmic heating of the substrate for REBCO film growth, direct tape temperature monitoring, and laminar precursor flow. This A-MOCVD method has been used to fabricate 4–5 <inline-formula><tex-math notation="LaTeX">$\mu$</tex-math></inline-formula>m thick film REBCO tapes with record-high performance: critical currents exceeding 8700 A/12 mm at 30 K, 3 T; and engineering current density of 5200 A/mm<inline-formula><tex-math notation="LaTeX">$^2$</tex-math></inline-formula> at 4.2 K, 15 T. Recently, we constructed a pilot-scale reel-to-reel A-MOCVD system to scale up the technology to long tapes. Preliminary batches of tapes exhibit consistent performance and good uniformity along the length. An in-line 2D X-ray Diffraction (XRD) system has been integrated into the pilot A-MOCVD tool to monitor the REBCO texture and composition, RE<inline-formula><tex-math notation="LaTeX">$_2$</tex-math></inline-formula>O<inline-formula><tex-math notation="LaTeX">$_3$</tex-math></inline-formula> content, and the dimensions of BaMO<inline-formula><tex-math notation="LaTeX">$_3$</tex-math></inline-formula> (BMO, M=Zr,Hf) nanorods that act as artificial pinning centers. Specifically, the streaking angle between REBCO (103) and BZO (101) has been found to correlate well with (Ba+M)/Cu of the film, lift factor in critical current over a range of temperatures and magnetic fields, and the size of the BMO nanorods. The in-line 2D-XRD is expected to serve as a valuable quality measuring tool supporting realtime feedback control for the process to yield uniform and consistent manufacturing of high-performance REBCO tapes by Advanced MOCVD.