Structural and electrical behaviour of glass ceramic 00B under sandwiched condition between two Crofer22APU substrates

Abstract

Obtaining high temperature glass and glass ceramic based seals is one of the biggest challenges in the present day fabrication of Solid Oxide Fuel Cell (SOFC) stacks. Formation of BaCrO 4 phase in BCAS glasses leads to degradation of cell performance. This work focusses on one glass composition derived from a BCAS species named 00B which is free of BaO and Al 2 O 3 contents. 00B was sandwiched between two Crofer22APU plates forming CGC sandwiches and heated for repeated thermal cycles from RT to 800 °C to check their compatibility with the metallic substrate. Microscopic images of the CGC interface and XRD data of the internal glass surface of the broken sandwich were recorded to observe the structural properties of the prepared sandwich. DC resistivity measurements of the glass under sandwiched conditions between two Crofer22APU plates, at RT and at elevated temperatures were carried out, to determine its resistivity at high temperatures, under SOFC operating conditions. The CGC sandwiches prepared using sample 00B showed good structural properties after repeated thermal cycles and sufficiently high specific resistance at room and elevated temperatures. The 00B glass without BaO and Al 2 O 3 content, but having structural and electrical behaviour suitable for coating on Crofer22APU, is suggested to be a potentially promising candidate for SOFC sealant applications.