Joining LaMO3 Perovskite Ceramics to Nickel-based Super Alloys using Brazing/TLPB Techniques
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Reliable alternative sealing techniques for Oxygen Transfer Membrane technologies applied in GTL processes was developed. Particularly, the interactions between nickel-based brazing alloys and LaMO3) perovskite membranes was described. Ni-based liquid alloys wet LaMo3 perovskite substrates without additions of active elements, e.g., Ti, Zr, etc. Relatively large contact area ceramic/metal joints were created using such alloys. Under certain joining conditions (low vacuum environments), crack-free specimens were obtained. However, even in these cases, micro-cracks were likely to nucleate in regions close to the ceramic/metal interface. Analysis of the interfacial reaction zone demonstrated that the presence of oxygen-active elements, e.g., chromium and iron in the nickel braze, created a relatively large oxygen chemical potential across the ceramic/metal interface. Such a large chemical potential caused the localized decomposition of the perovskite matrix and the formation of a high-porosity region parallel to the ceramic/metal interface.
author list (cited authors)
Arroyave, R., Eagar, T. W., & Larson, H.