Wentao Wang

Preparation and Performance of the Sm0.2Ce0.8O1.9-x Single Buffer Layer Fabricated with Dip-Coating

Abstract An epitaxial Sm 0.2 Ce 0.8 O 1.9- x (SCO) single buffer layer with thickness of about 250 nm has been deposited via dip-coating polymer-assisted chemical solution deposition (PACSD) approach for YBCO coated conductors on bi-axially textured Ni-5%W (200) alloy substrate. Flat, crack-free SCO films with sharp (200) c -axis orientation and texture have been obtained by carefully controlling the concentration of precursor solution, withdrawing speed, annealing temperature and dwelling time. Leaving other three factors unchanged, focuses on the influence of different withdrawing speeds on the performance of the SCO buffer layer has been focused on. YBCO superconducting layer has been deposited equally via dip-coating PACSD approach on the SCO-buffered NiW, showing a bi-axially texture. Micro-structural investigations revealed a homogeneous surface structure. Both of these indicate that SCO single buffer layer can function well as template. The approach has shown a promising way to fabricate long-length, low-cost YBCO coated conductors.

PREPARATION OF Sm0.2Ce0.8O1.9-X BUFFER BY REEL-TO-REEL SLOT-DIE COATING

Bi-axially textured Sm0.2Ce0.8O1.9-x (SCO) single buffer tape with the length of 110 cm and the thickness of 150 nm, has been prepared on textured NiW(200) alloy substrate by using the polymer assisted chemical solution deposition (PACSD) method combined with slot-die coating technique for REBCO coated conductors. Smooth, uniform and crack-free SCO tape with sharp (200) c-axis orientation and high texture has been obtained by controlling the viscosity of solution, the moving speed of tape and the release rate of solution, bi-lateral texture of tape has been more than 90%, the FWHM obtained from ω-scan and φ-scan on the center of the tape are 5.08° and 4.64°, respectively.

Influence of a Novel Heat Treatment on Structures and Superconducting Properties of YGdBCO Coated Conductors

Preliminary results for a future superconducting joint between YGdBCO coated conductors (CCs) were reported in this work. A promising heat treatment called as melting diffusion and texture merging to connect CCs was proposed and the influence of different treatment on the texture, the surface morphologies and the superconducting properties of YGdBCO CCs were investigated. The impurity phase such as (YGd)211 and BaCuO generated in partial melting stage can be transformed into textured (YGd)123 via low-temperature recrystallization, which is helpful to form textured interface between two CCs. With a comparison to the partial melting process, the superconducting properties of YGdBCO CCs with recrystallization after partial melting can be recovered in a shorter time of 75 h under flowing O2 gas. It demonstrates that this heat treatment is prospective to fabricate a superconducting joint for REBCO CCs. This joint work is undergoing in our group.