Glass–ceramic seals in the system MgO  BaO  B 2 O 3  SiO 2  operating under simulated SOFC conditions

Rodríguez-López, S.; Haanappel, V.A.C.; Durán, Alicia; Muñoz, Francisco; Mather, Glenn C.; Pascual, María J.; Groß-Barsnick, Sonja M.

doi:10.1016/j.ijhydene.2016.07.051

Cited by 37 publications

(14 citation statements)

References 33 publications

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“…A good processing control will also affect the long term resistance and stability of the joints within the environment of the coexisting oxidizing and reducing atmospheres of the cell (Weil, 2006). If the glass does not provide a good sealing ability, there will be areas of easy access for the gases in the joints seal/interconnect and seal/electrolyte interfaces, which will favor interfaces degradation and as a consequence deteriorate the joint through the formation of undesirable corrosion products (Haanappel et al, 2005;Rodríguez-López et al, 2016). Additionally, the seal itself and also its joints with the stack components must withstand different mechanical stresses resulting from the planar configuration and its modular character, including both compressive and tensile stresses .…”

Section: Introductionmentioning

confidence: 99%

Thermo-Mechanical Stability and Gas-Tightness of Glass-Ceramics Joints for SOFC in the System MgO-BaO/SrO-B2O3-SiO2

et al. 2020

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The objective of this paper is to illustrate a variety of studies carried out to improve the quality of some particular glass-ceramic joining materials based on measured properties such as gas-tightness and mechanical resistance and demonstrate the feasibility of using the proposed materials for solid oxide fuel cells (SOFC) and solid oxide electrolysis cells (SOEC) applications. First, the sealing conditions have been optimized for the two selected compositions in the system MgO-BaO/SrO-B 2 O 3 -SiO 2 . Once the joining materials have been optimized, the gas-tightness has been measured as a function of the glass-ceramic crystallization degree, its thermal cycling behavior and the influence of a reducing atmosphere on this property. The electrical resistance at high temperature has also been studied. Subsequently, the chemical compatibility of the joints steel/glass-ceramic has been evaluated by means of the analysis of the cross-sections using SEM and EDX. Furthermore, the mechanical and chemical stability of the joints has also been studied as a function of the crystallization degree, the resistance vs. thermal cycling and the influence of a reducing atmosphere. Finally, the mechanical resistance of the joints regarding flexural loading has been characterized employing a 4-point bending method both at room temperature and at relevant high temperatures varying the seal thickness. Overall, the results verify that the developed and tested materials are promising for long term stable SOFC and SOEC applications in advanced stack designs aiding prolonged lifetime under thermal-cyclic conditions.

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Section: Introductionmentioning

confidence: 99%

Thermo-Mechanical Stability and Gas-Tightness of Glass-Ceramics Joints for SOFC in the System MgO-BaO/SrO-B2O3-SiO2

et al. 2020

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“…Few other melting tests (not presented here) performed at lower temperature for glasses made with conventional or sol-gel routes, respectively at use of barium aluminosilicate glass-ceramics corresponds to the formation of BaCrO 4 crystalline phase (high CTE potentially leading to cracks) at the interface between the glasses and the metallic interconnector [7,[15][16][17][18]. However, promising performances had been obtained on short-term or on mid-term operations in air (up to 1500 h in dual atmosphere with no delamination [19]), in dual atmosphere (no delamination after 750 h [20]) or in real testing conditions with thermal cycles for SOFC applications [21]. In our previous works, we had developed a new sol-gel route to synthesize barium (boron) aluminosilicate glass sealants in order to process these glasses at a lower temperature than using a solid-state route and to improve the performance of these glasses for SOFC applications [22][23][24][25][26].…”

Section: Resultsmentioning

confidence: 98%

Optimization of the synthesis route of a barium boron aluminosilicate sealing glass for SOFC applications

Puig¹,

Prange²,

Arati³

et al. 2017

Ceramics International

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A barium boron aluminosilicate sealing glass for IT-SOFC or SOFC applications was synthesized using different routes. Notably, sol-gel and solid state processes were used in order to obtain homogeneous glasses at 1100-1300°C. Sol-gel processes consist in a soft chemistry route allowing a better homogeneity between cationic precursors in the mixture and a better reactivity of the material. The influence of the process and of the glass processing temperature on the thermo-mechanical properties of the glasses were investigated after different heat treatments in air atmosphere, i.e. glass processing, sealing (850°C-2 h) and ageing (800°C-100 h) procedures. It had been observed that the grain size of the glass powder (obtained after the glass processing and used for the sealing operation) is determining in order to manage the sealing procedure. Some large pores were formed during the devitrification step of the glass made by solid state route while glass sealants synthesized by the sol-gel route even at 1100°C remained suitable for SOFC applications after thermal treatments, which proved that the sol-gel process is useful to decrease the glass processing temperature.

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“…ZnO‐containing compositions have also been discarded for this application as ZnO increases the conductivity of seals leading to noncompliance of resistivity requirements. The ZnO addition also brings about an increase of steel corrosion in a dual atmosphere …”

Section: Resultsmentioning

confidence: 99%

Processing technologies for sealing glasses and glass‐ceramics

Pablos-Martín

Rodríguez-López

Pascual

2020

Int J of Appl Glass Sci

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This paper embraces two different approaches for the joining of materials through glass sealants. First, the conventional method of furnace sealing in which paste technology is normally employed. The glass sealant is applied in powder form mixed with agglomerant and with the help of dispenser robots, tape casting, or screen printing. Glass-ceramics for sealing of solid oxide fuel cells (SOFC) are described as an example of this type of processing. Glass composition, thermal properties, particle size of the glass powder, sintering and crystallization competition, and final crystalline phases together with a suitable chemical compatibility with the metallic and ceramic elements to be sealed need to be carefully adjusted for this specific application. Second, laser welding is presented as an alternative sealing technology. A general overview about laser welding through glass sealants is presented. Particularly, the welding of sapphire and fused silica glass through a BTS.2SiO 2 thin film glass sealant by employment of a nanosecond-pulsed laser is detailed. Laser parameters (frequency, power, scan speed, and number of passes) were optimized to get the best molten conditions of the BTS thin film, while allowing its crystallization. BTS crystallization upon laser welding leads to a strong blue emission upon UV excitation. Finally, both processing technologies were compared. K E Y W O R D Sadherence, crystallization, fresnoite, furnace sealing, glass-ceramics, laser welding, sinteringThis is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Glass–ceramic seals in the system MgO BaO B 2 O 3 SiO 2 operating under simulated SOFC conditions

Cited by 37 publications

References 33 publications

Thermo-Mechanical Stability and Gas-Tightness of Glass-Ceramics Joints for SOFC in the System MgO-BaO/SrO-B2O3-SiO2

Thermo-Mechanical Stability and Gas-Tightness of Glass-Ceramics Joints for SOFC in the System MgO-BaO/SrO-B2O3-SiO2

Optimization of the synthesis route of a barium boron aluminosilicate sealing glass for SOFC applications

Processing technologies for sealing glasses and glass‐ceramics

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