A novel Ag based sealant for solid oxide cells with a fully tunable thermal expansion

Si, Xiaoqing; Cao, Jian; Talic, Belma; Ritucci, Ilaria; Li, Chun; Qi, Junlei; Feng, Jicai; Kiebach, Ragnar

doi:10.1016/j.jallcom.2020.154608

Cited by 27 publications

(12 citation statements)

References 45 publications

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“…Moreover, the rapid growth of this oxide layer is proved to be a key factor for the RAB joint failure during aging [17]. The other issue for the Ag-CuO braze is that CuO is thermodynamically unstable when exposed to the reducing atmosphere in fuel (i.e., anode) chambers [7,31].…”

Section: Introductionmentioning

confidence: 99%

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Joining YSZ electrolyte to AISI 441 interconnect for solid oxide cells using the Ag interlayer: Enhanced mechanical and aging properties

Wang

et al. 2021

Preprint

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Conventional Ag-CuO braze can lead to two electrolyte/interconnect joining issues: over-oxidation at the steel interconnect and hydrogen-induced decomposition of CuO. This work demonstrates that a pure Ag interlayer, instead of Ag-CuO braze, can join YSZ electrolyte to AISI 441 interconnect in air. Reliable joining between YSZ and AISI 441 can be realized at 920 °C. A dense and thin oxide layer (~2 μm) is formed at the AISI 441 interface. Also, an interatomic joining at the YSZ/Ag interface is detected by TEM observation. Obtained joints display high shear strengths (~86.1 MPa), 161% higher than that of joints brazed by Ag-CuO braze (~33 MPa). After aging in reducing and oxidizing atmospheres (800 °C/300 h), joints remain tight and dense, indicating a better aging performance. This technique eliminates the CuO-induced issues, which will extend lifetimes for SOFC/SOEC stacks and other ceramic/metal joining applications.

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Section: Introductionmentioning

confidence: 99%

“…Glass/glass-ceramic bonding and reactive air brazing (RAB) are currently two promising methods to join cells to interconnects [17][18][19]. For the glass/glass-ceramic materials, their composition can be tailored to match the thermomechanical requirements of the SOFC/SOEC stack components [20,21].…”

Section: Introductionmentioning

confidence: 99%

Joining YSZ electrolyte to AISI 441 interconnect for solid oxide cells using the Ag interlayer: Enhanced mechanical and aging properties

Wang

et al. 2021

Preprint

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“…Glass/glass-ceramic bonding and reactive air brazing (RAB) are currently two promising methods to join cells to interconnects [22][23][24]. For the glass/glass-ceramic materials, their composition can be tailored to match the thermomechanical requirements of the SOFC/SOEC stack components [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

“…One is the thick and loose Cu/Cr/Mn/Fe-oxide layer (typically ≥20 µm) at the braze/interconnect interface due to the reaction between the CuO from the braze and the steel interconnect [31,37,38]. Moreover, the rapid growth of this oxide layer has been proven to be a key factor for the RAB joint failure during aging [22]. Another issue for the Ag-CuO braze is that CuO is thermodynamically unstable when exposed to the reducing atmosphere in fuel (i.e., anode) chambers [7,36].…”

Section: Introductionmentioning

confidence: 99%

Joining 3YSZ Electrolyte to AISI 441 Interconnect Using the Ag Particle Interlayer: Enhanced Mechanical and Aging Properties

Wang

et al. 2021

Crystals

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Reactive air brazing has been widely used in fabricating solid oxide fuel/electrolysis cell (SOFC/SOEC) stacks. However, the conventional Ag–CuO braze can lead to (I) over oxidation at the steel interconnect interface caused by its adverse reactions with the CuO and (II) many voids caused by the hydrogen-induced decomposition of CuO. The present work demonstrates that the Ag particle interlayer can be used to join yttria-stabilized zirconia (YSZ) electrolytes to AISI 441 interconnect in air instead of Ag–CuO braze. Reliable joining between YSZ and AISI 441 can be realized at 920 °C. A dense and thin oxide layer (~2 μm) is formed at the AISI 441 interface. Additionally, an interatomic joining at the YSZ/Ag interface was observed by TEM. Obtained joints displayed a shear strength of ~86.1 MPa, 161% higher than that of the joints brazed by Ag–CuO braze (~33 MPa). After aging in reducing and oxidizing atmospheres (800 °C/300 h), joints remained tight and dense, indicating a better aging performance. This technique eliminates the CuO-induced issues, which may extend lifetimes for SOFC/SOEC stacks and other ceramic/metal joining applications.

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“…For decades, related brazing studies mainly focused on the joining between YSZ electrolyte and ferrite-based metal-interconnect, evolution of interfacial microstructures, and hermetic properties after exposure to long-term operation at elevated temperatures (17)(18)(19). Recently more researches have been concentrated on tailoring the thermal expansion of Ag-based fillers by mixing ceramic particles (20)(21). However, there were little literature to adopt SOFC brazed-seal using LSGM or GDC as electrolyte.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Ag-Based Filler for Electrolyte/Metallic-Interconnect Joint in Metal-Supported Solid Oxide Fuel Cells Applications

et al. 2021

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Metal-supported solid oxide fuel cells (MS-SOFCs) exhibit better electrochemical performance than conventional ceramic-supported cells at lower temperature due to their exceptional thermal, electrical, and mechanical properties. MS-SOFCs can withstand rapid thermal cycling operation and make it practical for mobile applications. A reliable seal is essential for electrolyte/metallic interconnect joint in MS-SOFC applications. In the present study, we proposed an Ag-Ge alloy filler as a high-temperature brazing sealant for use in MS-SOFCs. Commercial ferritic stainless steel (Crofer22H) and La1-XSrXGa1-yMgyO3- δ (LSGM) substrate were employed as metallic interconnect and electrolyte for this study, respectively. The adhesive and hermetic characterization for the electrolyte/metallic interconnect joint joined by the Ag-Ge alloy filler were examined by using high-temperature leak test at elevated temperatures. Results showed that the leak rate of LSGM/Crofer22H coupon is 5.0 x 10-4 mbar∙l/s/cm after aging at 750°C for 100 hours in He/air. In addition, SEM/EDS analyses also revealed that Ge element in the Ag-Ge filler is prone to diffuse toward Crofer22H and LSGM side, and thus improves the interfacial adhesion of the LSGM/Crofer22H joint.

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A novel Ag based sealant for solid oxide cells with a fully tunable thermal expansion

Cited by 27 publications

References 45 publications

Joining YSZ electrolyte to AISI 441 interconnect for solid oxide cells using the Ag interlayer: Enhanced mechanical and aging properties

Joining YSZ electrolyte to AISI 441 interconnect for solid oxide cells using the Ag interlayer: Enhanced mechanical and aging properties

Joining 3YSZ Electrolyte to AISI 441 Interconnect Using the Ag Particle Interlayer: Enhanced Mechanical and Aging Properties

Characterization of Ag-Based Filler for Electrolyte/Metallic-Interconnect Joint in Metal-Supported Solid Oxide Fuel Cells Applications

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