Coated Conductor: Some Critical Aspects from Substrate to Device
This work reports some new studies related to critical aspects in the development of coated conductors (CC). New bi-axially textured tapes based on commercial copper alloys were fabricated and tested as substrates for LZO buffer layer deposited by chemical solution deposition (CSD). Such a layer form cube texture on NiW5 and Cu55Ni45 with an identical or even better texture than that of the substrate. It was shown that a S c(2x2) sub-layer formed at the metallic surface as a positive effect on the nucleation. The crystallisation of LZO on Cu55Ni45 still has to be improved, being inhibited by trapped C in the film. Recent progresses using our continuous MOCVD system are shown. A CC fabricated by an all MOCVD process has been obtained on SS/YSZIBAD substrate with high transport critical current (170 A/cm-width, at 77 K). It is also shown that LZOMOD can efficiently protect Ni5W RABITS from oxidation during deposition of CeO2 layer by MOCVD under 30-40% O2 partial pressure. This opens the possibility to fabricate a CC on RABITS by MOCVD. This shows that a mixed MOD/MOCVD approach could be efficient. Finally a 2m long CC SS/YSZIBAD has been tested for fault current limiter applications. Best limitation was observed at 86 K where an equivalent energy of 340 J has been dissipated in the CC during 12 ms without apparent damage of the CC. In a subsequent operation, the CC was however destroyed. The causes are discussed in the perspective to design better architectures for this application.
Yafang Han et al.
P. Odier et al., "Coated Conductor: Some Critical Aspects from Substrate to Device", Materials Science Forum, Vols. 546-549, pp. 1855-1864, 2007