ISSN:
1551-2916
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
Notes:
A nonvacuum reel-to-reel dip-coating system has been used to continuously fabricate epitaxial Gd2O3 buffer layers on mechanically strengthened, biaxially textured Ni–(3 at.% W–1.7 at.% Fe), defined as Ni-alloy, metal tapes. Because of its significance as a seed layer, optimum processing conditions (postannealing speed and temperature) of Gd2O3 buffer layers have been studied. Highly textured films were obtained under reducing (96% Ar + 4% H2) atmosphere at temperatures between 1100° and 1150°C; postannealing speed did not significantly affect the crystalline quality of the Gd2O3. Scanning electron microscopy revealed a continuous, dense, and crack-free surface morphology for these dip-coated buffers. The Gd2O3 layer thickness led to pronounced differences in the growth characteristics of the subsequent YSZ and CeO2 layers deposited by rf-magnetron sputtering. Epitaxial YBCO films grown by pulsed laser deposition on the short prototype CeO2/YSZ/Gd2O3/Ni–(3 at.% W–1.7 at.% Fe) conductors yielded self-field critical current densities (Jc) as high as 1.2 × 106 A/cm2 at 77 K. Pure Ni tapes were used to assess the viability of dip-coated buffers for long length coated conductor fabrication. The YBCO films, grown on 80 cm long and 1 cm wide CeO2/YSZ/Gd2O3 buffered Ni tapes by the industrially scalable ex situ BaF2 precursor process, exhibited end-to-end self-field Jc values of 6.25 × 105 A/cm2 at 77 K. These results demonstrate the reproducible epitaxy of solution-derived seed layers on pure Ni and Ni-alloy tapes as well as underscore the viability of solution approaches for the production of long length YBCO-based coated conductors.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1151-2916.2003.tb00009.x
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