Reaction of YBa$_2$Cu$_3$O$_{7−x}$ (YBCO) and fused silica in YBCO glass fibres

[摘要] This work introduces the first reported experiments on drawing YBa$_2$Cu$_3$O$_{7−x}$ (YBCO) into fibres with a fused silica cladding using a fibre draw tower to manufacture YBCO glass fibres. These fibre draw experiments allowed manufacturing fibre sections with core diameters between 50 and 200 $\mu$m and a length of around 1.2 m. However, reactionsbetween the fused silica cladding and the YBCO core were revealed by the fibre drawing process. Therefore, this study focusses on investigating these reactions (in as-drawn fibres as well as after additional heat-treatments) using energy dispersive spectroscopy analyses on an environmental scanning electron microscope as well as using X-ray photoelectron spectroscopyanalyses and a cross-polarized light study. The results showed the formation of silica precipitations inside the as-drawn YBCO core, forming an interface layer between the core and the cladding regions, as well as the presence of a high silicon content inside the core with a possible silicate formation. Additional heat-treatments have shown the formation of silica and copper oxide co-precipitations at 900$^{\circ}$C. In addition, heat-treatments at higher temperatures have shown the occurrence of further reactions, which led to a degradation of the core and the formation of new phases.

[学科分类] 材料工程

[关键词] YBa$_2$Cu$_3$O$_{7−x}$;YBCO core glass fibres;YBCO–silica reaction phases;superconductor wires.