Reaction of $$\hbox {YBa}_{2}\hbox {Cu}_{3}\hbox {O}_{7-x}$$ (YBCO) and fused silica in YBCO glass fibres

Abstract

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 μm and a length of around 1.2 m. However, reactions between 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 spectroscopy analyses 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 • 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. Keywords. YBa 2 Cu 3 O 7−x ; YBCO core glass fibres; YBCO-silica reaction phases; superconductor wires.

Dissolution and Diffusion-Based Reactions within YBa2Cu3O7−x Glass Fibers

“…A detailed description of the manufacturing process of YBCO glass fibers in vacuum is presented in our previous work in [14]. The drawing temperatures used were~2000 • C. In the current work, in addition to the use of vacuum as the drawing atmosphere, YBCO glass-clad fibers were drawn under oxygen atmosphere.…”

“…Heat-treatment studies on the vacuum as-drawn fiber sections revealed, furthermore, the formation of cuprite and silica-rich co-precipitations at 900 • C. In addition, heat-treatments at higher temperatures showed the formation of yttrium-barium-rich and barium-copper-rich phases. Even though [14] presented important preliminary results on the reaction processes within YBCO glass-clad fibers, it did not perform an in-depth analysis of the occurring dissolution and diffusion based processes, as is carried out in the current work. Indeed, herein, we focus on identifying and analyzing the dissolution and diffusion based reactions within YBCO glass fibers and on defining the phase relations within the YBCO-SiO 2 system.…”

“…Our previous work in [14] used the molten-core approach to draw YBa 2 Cu 3 O 7−x (YBCO) into glass fibers, with the goal of studying the feasibility of obtaining superconductive YBCO glass fibers. Energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and a cross-polarized light study revealed the occurrence of reactions between the YBCO core and the fused silica cladding in vacuum as-drawn fibers as well as after additional heat-treatments.…”

“…Energy dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and a cross-polarized light study revealed the occurrence of reactions between the YBCO core and the fused silica cladding in vacuum as-drawn fibers as well as after additional heat-treatments. In particular, from the study in [14], we determined that vacuum as-drawn YBCO glass fibers exhibit a core/cladding interface region, which contains silica-rich precipitations. Heat-treatment studies on the vacuum as-drawn fiber sections revealed, furthermore, the formation of cuprite and silica-rich co-precipitations at 900 • C. In addition, heat-treatments at higher temperatures showed the formation of yttrium-barium-rich and barium-copper-rich phases.…”

Powder-in-Tube Reactive Molten-Core Fabrication of Glass-Clad BaO-TiO2-SiO2 Glass–Ceramic Fibers

“…On the other hand, reactive molten-core fabrication has proven to be an effective method to fabricate fibers with core materials which cannot be drawn into fibers on their own [22][23][24]. With the housing material reacting with the core material via various mechanisms, such as reactive chemistry, dissolution, and diffusion, fibers with various core materials, such as semiconductors, special glass, and crystalline oxides, have been reported [22][23][24][25][26][27][28][29][30]. Therefore, in this paper we report on the fabrication of glass-clad BTS glass-ceramic fibers using the powder-in-tube reactive molten-core approach with a successive isothermal heat treatment.…”