Wetting and Mechanical Characteristics of the Reactive Air Braze for Yttria‐Stabilized Zirconia (YSZ) Joining

Kim, J. Y.; Weil, K. Scott; Hardy, John S.

doi:10.1002/9781118407141.ch11

Cited by 3 publications

(3 citation statements)

References 5 publications

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“…The Ag–4CuO filler consisted of both L1 and L2 liquid phases. Previous studies have suggested that the L1 liquid phase showed a high affinity for Al 2 O 3 , ZrO 2 , and perovskite ceramics and was easily enriched on their surfaces 26,40–42 . When brazing with Ag–4CuO filler, more intensely interfacial reactions happened as CuO in the L1 liquid phase tended to react with the Al 2 O 3 layer.…”

Section: Resultsmentioning

confidence: 95%

“…Previous studies have suggested that the L1 liquid phase showed a high affinity for Al 2 O 3 , ZrO 2 , and perovskite ceramics and was easily enriched on their surfaces. 26,[40][41][42] When brazing with Ag-4CuO filler, more intensely interfacial reactions happened as CuO in the L1 liquid phase tended to react with the Al 2 O 3 layer. The interfacial reaction was gradually weakened as the CuO content in the L1 liquid phase decreased with the increase of the brazing temperature.…”

Section: Effect Of Brazing Temperature On Interfacial Microstructurementioning

confidence: 99%

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Reactive air brazing of 3YSZ ceramic to aluminized Crofer22H stainless steel using Ag–CuO fillers

Zhou

Yang

et al. 2022

Int J Applied Ceramic Tech

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In this work, an effective protected Al2O3 layer was fabricated first on the surface of Crofer22H by reactive air aluminization to suppress cathodic poisoning in solid oxide fuel cells. Then, the reactive air brazing of aluminized Crofer22H to 3YSZ ceramics was carried out by using Ag–CuO fillers. The effects of CuO content and brazing temperature on the interfacial microstructure and mechanical properties of the joints were studied in detail. The results indicated that maintaining a continuous Al2O3 layer was the prerequisite for achieving a reliable joint. And the interfacial reaction gradually became intense with the increase of CuO content, and the continuity of the Al2O3 layer was disrupted as it was increased to 6 mol%. The well‐connected joints could be achieved when brazing at 970–1100°C with Ag–2CuO filler. The interfacial microstructure did not obviously change with increasing temperature, and the joint strength was stable at ∼35 MPa. While the interfacial reaction gradually weakened with increasing temperature as brazing with Ag–4CuO filler, the well‐connected joints were obtained when brazing above 1000°C, and the maximum shear strength of ∼44.3 MPa was obtained when brazing at 1050°C for 30 min.

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Section: Resultsmentioning

confidence: 95%

Section: Effect Of Brazing Temperature On Interfacial Microstructurementioning

confidence: 99%

Reactive air brazing of 3YSZ ceramic to aluminized Crofer22H stainless steel using Ag–CuO fillers

Zhou

Yang

et al. 2022

Int J Applied Ceramic Tech

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“…The principle of RAB is to use a molten oxide (commonly copper) dissolved in a noble metal solvent (commonly silver) to prewet the ceramic surfaces, in this way shaping a new surface that is more wettable by the remaining molten filler braze metal [3,29]. The wetting of ceramics is possible due to in situ formed oxides in the melted braze during the brazing process [29].The wetting of the ceramic is caused by the partial miscibility gap of the AgCuO-system [29][30][31][32]. The emerging joint is well adherent, ductile, and basically oxidation resistant [3,18].…”

Section: Introductionmentioning

confidence: 99%

Mechanical behavior of reactive air brazed (RAB) Crofer 22 APU-Al2O3 joints at ambient temperature

2020

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The evolution of innovative high-temperature electrochemical devices, such as high temperature solid oxide fuel cells (SOFCs), gas separators and gas reformers, consisting of metal-ceramic-joints is challenging. The seals have to be stable and gastight in isothermal high-temperature as well as in thermo-cyclic operation. Here, the reduction of porosity is the primary aim, to obtain air brazed joints with a long lifetime. In the last years, reactive air brazing (RAB) has gained rising interest for the joining of ceramic-ceramic and ceramic-metal compounds. In this paper an alternative brazing filler metal manufacturing process employing (physical vapor deposition (PVD)) is applied and its feasibility for the production of metal-ceramic composites has been investigated for Ag-4 wt%CuO. For RAB aluminum oxide with ferritic high chromium steel Crofer22APU have been joined. The pore formation in subordination of the braze and base materials can be monitored after brazing. By modifying the brazing process, the pore formation in the joints can be avoided. The microstructure of brazed joints with the developed braze foils is studied. Discussion of the results focuses on the influence of microstructural evolution on mechanical properties, the pore formation in the brazing seam and failure behavior of the brazed joints. A correlation between the process parameters brazing temperature and holding time and the achieved compound properties could be derived. Further, excellent wetting of the ceramic was obtained. The highest shear strength with 123 MPa was measured for a temperature of 1000 °C and 5 min, using the Ag4CuO alloy.

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Microstructure and Mechanical Properties of Reactive-Air-Brazed 3YSZ/Crofer 22 APU Joints at Ambient Temperature

Tillmann

Anar

Wojarski

et al. 2020

Metallogr. Microstruct. Anal.

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Wetting and Mechanical Characteristics of the Reactive Air Braze for Yttria‐Stabilized Zirconia (YSZ) Joining

Cited by 3 publications

References 5 publications

Reactive air brazing of 3YSZ ceramic to aluminized Crofer22H stainless steel using Ag–CuO fillers

Reactive air brazing of 3YSZ ceramic to aluminized Crofer22H stainless steel using Ag–CuO fillers

Mechanical behavior of reactive air brazed (RAB) Crofer 22 APU-Al2O3 joints at ambient temperature

Microstructure and Mechanical Properties of Reactive-Air-Brazed 3YSZ/Crofer 22 APU Joints at Ambient Temperature

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