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Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging

The separation of oxygen from air by means of inorganic ceramic membranes requires gas-tight ceramic–metal joints that enable reliable permeation operation in the oxygen partial pressure gradient at 850 °C. Reactive air brazing is a promising method to solve this challenge. However, reactive air bra...

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Detalles Bibliográficos
Autores principales: Herzog, Simone, Kaletsch, Anke, Broeckmann, Christoph
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10221055/
https://www.ncbi.nlm.nih.gov/pubmed/37233565
http://dx.doi.org/10.3390/membranes13050504
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author Herzog, Simone
Kaletsch, Anke
Broeckmann, Christoph
author_facet Herzog, Simone
Kaletsch, Anke
Broeckmann, Christoph
author_sort Herzog, Simone
collection PubMed
description The separation of oxygen from air by means of inorganic ceramic membranes requires gas-tight ceramic–metal joints that enable reliable permeation operation in the oxygen partial pressure gradient at 850 °C. Reactive air brazing is a promising method to solve this challenge. However, reactive air brazed BSCF membranes suffer from a significant strength degradation that is caused by unhindered diffusion from the metal component during aging. In this study, we investigated how diffusion layers applied on the austenitic steel AISI 314 influence the bending strength of BSCF-Ag3CuO-AISI314 joints after aging. Three different approaches were compared as diffusion barriers: (1) aluminizing via pack cementation, (2) spray coating with NiCoCrAlReY, and (3) spray coating with NiCoCrAlReY and an additional 7YSZ top layer. Coated steel components were brazed to bending bars and aged for 1000 h at 850 °C in air prior to four-point bending and subsequent macroscopic as well microscopic analyses. In particular, coating with NiCoCrAlReY showed low-defect microstructures. The characteristic joint strength was raised from 17 MPa to 35 MPa after 1000 h aging at 850 °C. In addition, the dominant delamination fracture between the steel and the mixed oxide layer, observed in the reference series with uncoated steel, could be replaced by mixed and ceramic fractures of higher strength. The effect of residual joint stresses on the crack formation and path is analyzed and discussed. Chromium poisoning could no longer be detected in the BSCF, and interdiffusion through the braze was effectively reduced. Since the strength degradation of reactive air brazed joints is mainly caused by the metallic joining partner, the findings on the effect of the diffusion barriers in BSCF joints might be transferred to numerous other joining systems.
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spelling pubmed-102210552023-05-28 Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging Herzog, Simone Kaletsch, Anke Broeckmann, Christoph Membranes (Basel) Article The separation of oxygen from air by means of inorganic ceramic membranes requires gas-tight ceramic–metal joints that enable reliable permeation operation in the oxygen partial pressure gradient at 850 °C. Reactive air brazing is a promising method to solve this challenge. However, reactive air brazed BSCF membranes suffer from a significant strength degradation that is caused by unhindered diffusion from the metal component during aging. In this study, we investigated how diffusion layers applied on the austenitic steel AISI 314 influence the bending strength of BSCF-Ag3CuO-AISI314 joints after aging. Three different approaches were compared as diffusion barriers: (1) aluminizing via pack cementation, (2) spray coating with NiCoCrAlReY, and (3) spray coating with NiCoCrAlReY and an additional 7YSZ top layer. Coated steel components were brazed to bending bars and aged for 1000 h at 850 °C in air prior to four-point bending and subsequent macroscopic as well microscopic analyses. In particular, coating with NiCoCrAlReY showed low-defect microstructures. The characteristic joint strength was raised from 17 MPa to 35 MPa after 1000 h aging at 850 °C. In addition, the dominant delamination fracture between the steel and the mixed oxide layer, observed in the reference series with uncoated steel, could be replaced by mixed and ceramic fractures of higher strength. The effect of residual joint stresses on the crack formation and path is analyzed and discussed. Chromium poisoning could no longer be detected in the BSCF, and interdiffusion through the braze was effectively reduced. Since the strength degradation of reactive air brazed joints is mainly caused by the metallic joining partner, the findings on the effect of the diffusion barriers in BSCF joints might be transferred to numerous other joining systems. MDPI 2023-05-10 /pmc/articles/PMC10221055/ /pubmed/37233565 http://dx.doi.org/10.3390/membranes13050504 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Herzog, Simone
Kaletsch, Anke
Broeckmann, Christoph
Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging
title Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging
title_full Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging
title_fullStr Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging
title_full_unstemmed Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging
title_short Diffusion Barriers Minimizing the Strength Degradation of Reactive Air Brazed Ba(0.5)Sr(0.5)Co(0.8)Fe(0.2)O(3-δ) Membranes during Aging
title_sort diffusion barriers minimizing the strength degradation of reactive air brazed ba(0.5)sr(0.5)co(0.8)fe(0.2)o(3-δ) membranes during aging
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10221055/
https://www.ncbi.nlm.nih.gov/pubmed/37233565
http://dx.doi.org/10.3390/membranes13050504
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