Manufacture of YBCO Superconducting Flexible Tapes from Nanoparticel Films Derived from Sedimentation and by Flame Depostion of Nanoparticles from Solution

The objective of this CRADA was to develop the experimental and theoretical basis of a technology to produce yttrium barium copper oxide (YBCO) superconducting flexible tapes derived from nanoparticle metal oxide sols. The CRADA was a joint effort between Oxford Superconducting Technology, Brookhaven National Laboratory and Karpov Institute of Physical Chemistry. The effort was divided into three main tasks, the synthesis of a heteroepitaxial oxide buffer layer, and the manufacture of a flexible biaxially textured metallic substrate and the synthesis of a heteroepitaxial crystalline YBCO layer. The formation of a heteroepitaxial buffer layer was implemented using technology developed at the Karpov Institute of Physical Chemistry for the synthesis, stabilization and deposition of polymer stabilized nanoparticle metal oxide sols. Using this technology, flexible oriented RABiTS nickel tapes, manufactured and supplied by the CRADA partner, Oxford Superconducting Technology, Carteret, New Jersey, were coated with a film of metal oxide nanoparticles. After coating the RABiTS nickel tapes with the nanoparticle sols the nickel tape/nanoparticle composite structure was sintered in order to form a dense crystalline heteroepitaxial oxide layer on the surface of the tape, also known as a ‘buffer’ layer. The final phase of the research was the formation of a heteroepitaxial YBCO layer, grown on top of the metal oxide buffer layer. This work was scheduled to follow the development of the heteroepitaxial oxide buffer layer as described above. Three different polymer stabilized sols, yttrium hydroxide, Y(OH){sub 3}, copper hydroxide, Cu(OH){sub 2}, and barium fluoride, BaF{sub 2}, were synthesized and combined in the appropriate stoichiometric ratio. This metal oxide sol was then be deposited onto the buffer layer and reacted to form a crystalline heteroepitaxial YBCO film ranging from 1–5 microns thick