Interface degradation of glass-to-metal seals during thermo-oxidative aging

Li, Shenhou; Cai, Yangyang; Zhu, Qinglin; Liu, Zheng; Zhang, Yong

doi:10.1016/j.corsci.2022.110189

Cited by 4 publications

(5 citation statements)

References 18 publications

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“…The sealing glass was fabricated by a thoroughly mixing process that has been previously described in detail [22]. Figure 1 shows a schematic diagram of the production processes using the PM and CM methods.…”

Section: Experimental Procedures 21 Sample Preparationmentioning

confidence: 99%

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Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Gong

Cai

Liu

et al. 2023

Mater. Res. Express

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In order to evaluate the influence of preform preparation processes on thermal cycle stability of glass-to-metal seals, this work embraced two different methods to produce the preform for seals. For the conventional powder metallurgy (PM) method, the molten glass was quenched to form frits, then the frits were ball milled to prepare glass powders. These glass powders were pressed into green bodies and heated to prepare preforms. While for the casting-machining (CM) method, the molten glass was cast into a graphite mold and annealed before accurate machining to preforms. In contrast to the PM method, the CM method provided an ultralow-porosity preform structure and a low porosity glass seal region. Field emission scanning electron microscope (FE-SEM) was conducted to investigate the bubbles and cracks in glass region. Furthermore, thermal cycling tests confirmed that these two tremendously different glass regions strongly affected the thermal cycle stability of the seals. To support the understanding of cracking in seals, the damage features of the samples were observed by FE-SEM and the extended finite element method (XFEM) was used to simulate the crack initiation and propagation. The experimental results demonstrated that cracking in the seals made from CM preforms occurred in the glass region near the sealing interface. However, cracks initiated from the bubbles in the seals made from PM preforms, which was verified by the XFEM simulation results. In addition, the CM seals demonstrated little degradation of the leakage rate until 105 thermal cycles, while cracking was found in the PM seals after 70 thermal cycles, indicating a decreased thermal cycle stability and resulting in hermetic failure.

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Section: Experimental Procedures 21 Sample Preparationmentioning

confidence: 99%

“…The process parameters of these two methods were determined through the previous studies of our group [22][23][24]. Briefly, molten glass with the appropriate composition was prepared using reagent-grade oxides and carbonates as raw materials.…”

Section: Experimental Procedures 21 Sample Preparationmentioning

confidence: 99%

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Gong

Cai

Liu

et al. 2023

Mater. Res. Express

Self Cite

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“…Rigidly bond seals could form a tight junction between seals and adjacent components. So far, most sealing developments have focused on rigidly bond seals, which are mainly categorized into glass and glass-ceramic seals [ 14 , 15 , 16 , 17 , 18 , 19 ]. The glass could infiltrate into adjacent components and form strong bonding at the interface.…”

Section: Introductionmentioning

confidence: 99%

Investigation on Long-Term Stability of Vermiculite Seals for Reversible Solid Oxide Cell

et al. 2023

Molecules

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A reversible solid oxide cell (RSOC) integrating solid oxide fuel (SOFC) and a solid oxide electrolysis cell (SOEC) usually utilizes compressive seals. In this work, the vermiculite seals of various thickness and compressive load during thermal cycles and long-term operation were investigated. The leakage rates of seals were gradually increased with increasing thickness and input gas pressure. The thinner seals had good sealing performance. The compressive load was carried out at thinner seals, the possible holes were squeezed, and finally the leakage rates were lower. With a fixed input gas pressure of 1 psi, 2 psi, and 3 psi, the leakage rates of 0.50 mm vermiculite remained at around 0.009 sccm/cm, 0.017 sccm/cm and 0.028 sccm/cm during twenty thermal cycles, while the leakage rates remained at around 0.011 sccm/cm for about 240 h. Simultaneously, elemental diffusions between seals and components were limited, implying good compatibility. Furthermore, the open circuit voltage (OCV) remained at around 1.04 V during 17 thermal cycles, which is close to Nernst potentials. The stack performance confirmed that the vermiculite seals can meet the structural support and sealing requirements. Therefore, the vermiculite shows good promise for application in stacks during thermal cycles and long-term operation.

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“…Both studies and experience demonstrate that the interface is a weakness of composite insulation equipment [9,10]. Interfaces are often damaged by ageing and superficial erosion and cause cascading failures during long-term operations.…”

Section: Introductionmentioning

confidence: 99%

Influence characteristics of water penetration on fibre‐reinforced polymer/rigid polyurethane foam interface of the composite cross‐arm considering natural ageing

et al. 2023

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Fibre‐reinforced polymer (FRP)/rigid polyurethane foam (RPUF) interface is susceptible to moisture intrusion in addition to natural ageing during operation. This study investigated the influence of moisture intrusion on the FRP/RPUF interface under natural ageing using experiments and molecular dynamics (MD) simulations. Water absorption, shear strength, and leakage current tests were used to clarify the changes in the interface performance. The degradation mechanism of moisture intrusion at the interface under natural ageing was revealed by MD simulation and micro‐characterisation. The results show that the natural ageing of interfacial materials will slightly reduce the quality of the interface but will reduce the water resistance of the material and promote the process of water intrusion into the interface. In addition, water mainly invades the interface through RPUF. After water penetration, the interfacial bonding strength and insulation performance significantly decreased. Plasticisation and hydrolysis of interfacial materials are the main reasons for decreased interfacial adhesion. Hydrolysis can cause irreversible damage to the interface, increasing interface defects and water absorption. The vicious cycle of material hydrolysis is the ultimate cause of interfacial debonding. The polar molecules produced by this process and the water absorbed by the interface caused the degradation of the interface insulation performance.

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Interface degradation of glass-to-metal seals during thermo-oxidative aging

Cited by 4 publications

References 18 publications

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Thermal cycle stability of glass-to-metal seals with glass preforms produced via powder-metallurgy and casting-machining methods

Investigation on Long-Term Stability of Vermiculite Seals for Reversible Solid Oxide Cell

Influence characteristics of water penetration on fibre‐reinforced polymer/rigid polyurethane foam interface of the composite cross‐arm considering natural ageing

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