University of Hertfordshire

  • Antonio G. Sabato
  • Axel Rost
  • Jochen Schilm
  • Mihails Kusnezoff
  • Milena Salvo
  • Andreas Chrysanthou
  • Federico Smeacetto
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Original languageEnglish
Number of pages10
Pages (from-to)15-24
JournalJournal of Power Sources
Journal publication date1 Mar 2019
Volume415
Early online date24 Jan 2019
DOIs
Publication statusPublished - 1 Mar 2019

Abstract

A new alkali-containing diopside based glass-ceramic sealant for solid oxide cells was synthesized, characterized and tested. The composition was designed to match the coefficient of thermal expansion (CTE) of Crofer22APU interconnect. The sealant has a glass transition temperature of 600°C, a crystallization peak temperature of 850°C and a maximum shrinkage temperature of 700°C, thus suggesting effective densification prior to crystallization. The CTE of the glass-ceramic is 11.5 10-6 K-1, a value which is compatible with the CTE for Crofer22APU stainless steel. Crofer22APU/glass-ceramic/Crofer22APU joined samples were tested in simulated real-life operating conditions at 800°C in dual atmosphere under an applied voltage, monitoring the electrical resistivity. The effect of two different applied voltages (0.7V and 1.3V) was evaluated. A voltage of 1.3V led to a rapid decrease in the electrical resistivity during the test;such a drop was due to the formation of Cr2O3 “bridges” that connected the two Crofer22APU plates separated by the sealant. There was no decrease in the resistivity when a voltage of 0.7V was applied. Instead,resistivity value remained stable at around 105 Ω cm for the 100h test duration. The degradation mechanisms, due to both the alkali content and the applied voltage, are investigated and discussed.

Notes

© 2019 Elsevier B.V. All rights reserved.

ID: 16218155