Melilite glass-ceramic sealants for solid oxide fuel cells: effects of ZrO2 additions assessed by microscopy, diffraction and solid-state NMR
authors Reddy, AA; Tulyaganov, DU; Goel, A; Sardo, M; Wiper, PV; Pascual, MJ; Kharton, VV; Kolotygin, VA; Tsipis, EV; Mafra, L; Ferreira, JMF
nationality International
journal JOURNAL OF MATERIALS CHEMISTRY A
keywords SI-29 MAS-NMR; ALUMINOSILICATE GLASSES; QUADRUPOLAR NUCLEI; SINTERING BEHAVIOR; PLANAR SOFCS; SILICATE; SPECTROSCOPY; CALCIUM; CRYSTALLIZATION; OPTIMIZATION
abstract The influence of adding 0-5 mol% zirconia (ZrO2) to a series of melt-quenched alkaline-earth aluminosilicate glasses designed in the gehlenite (Ca2Al2SiO7)-akermanite (Ca2MgSi2O7) system has been investigated for their potential application as sealants for solid oxide fuel cells (SOFCs). The work was implemented with a dual aim of improving the sintering ability of the glass system under consideration and gaining insight into the structural changes induced by ZrO2 additions in the glasses consequentially leading to their enhanced long-term thermal stability. That the degree of condensation of SiO4 tetrahedra increased with increasing amounts of zirconia was confirmed by Si-29 magic-angle (MAS) NMR. 1D Al-27, B-11 MAS as well as two-dimensional (2D) B-11 MQMAS/STMAS NMR experiments gave structural insight into the number and nature of aluminum and boron sites found in the glass and glass-ceramic (GC) samples. Irrespective of the heat treatment time, increasing the zirconia content in glasses suppressed their tendency towards devitrification, while the glasses exhibited good sintering behavior resulting in mechanically strong GCs with higher amounts of residual glassy phase making them suitable for self-healing during SOFC operation. All the GCs exhibited low total electrical conductivity; appropriate coefficients of thermal expansion (CTE), good joining and minimal reactivity with SOFC metallic components at the fuel cell operating temperature, thus, qualifying them for further appraisal in SOFC stacks.
publisher ROYAL SOC CHEMISTRY
issn 2050-7488
year published 2013
volume 1
issue 21
beginning page 6471
ending page 6480
digital object identifier (doi) 10.1039/c3ta10789b
web of science category Chemistry, Physical; Energy & Fuels; Materials Science, Multidisciplinary
subject category Chemistry; Energy & Fuels; Materials Science
unique article identifier WOS:000318565700023
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journal impact factor 9.931
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