Enhancing Hastelloy tape surfaces flattening efficiency via autonomously designed SDP system derived Y2O3 coatings

The widespread application of second-generation high-temperature superconducting (2G HTS) tapes has elevated demand for surface smoothing of long-length Hastelloy tapes utilizing simple and low-cost strategies. Amorphous Y 2 O 3 has been used to flatten the long-length Hastelloy tape surfaces via solution deposition planarization (SDP). In this work, the autonomously designed SDP system is applied to flatten the Hastelloy surface while significantly increasing progress rate. As a result, lifting speed up to 75 m/h, while the root mean square (RMS) roughness on Hastelloy tape surfaces was reduced from 28.13 nm to 0.76 nm over 5 × 5 μm² areas. These are superior to those of the state-of-the-art SDP lifting speeds. Additionally, the surface flattening process was elaborated through power spectral density (PSD). The Hastelloy tape surfaces have been confirmed to form a well-biaxially textured MgO buffer layer. The autonomously designed SDP system shed light on an effective strategy for flattening long-length Hastelloy tape surfaces.