Microstructural Characterization of 8YSZ/430 stainless Steel Joint using Ag-Cu-Ti Interlayers for Solid Oxide Full Cells Application
| Autor: | He-Sheng Chen, 陳鶴升 |
|---|---|
| Rok vydání: | 2017 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 105 The research use sliver-based interlayers (68.8Ag-26.7Cu-4.5Ti), were selected to join yttria-stabilized zirconia (YSZ) and 430 stainless steel for solid oxide fuel cells (SOFCs). The microstructural characterization on the interfaces of joints was performed by scanning electron microscopy (SEM), each equipped with an energy dispersive spectroscope (EDS). The diffusion of elements and bonding strength of 430 stainless steel/metallic interlayers/8YSZ joints were also evaluated. Microstructures and mechanical properties of joints were correlated to evaluate which metallic interlayers are suitable for SOFC. In the 430 stainless steel/68.8Ag–26.7Cu–4.5Ti interlayer/8YSZ joint, most of the Ag-rich phase and Cu-rich phase compositionthe, Fe from the steel reacted with Ti of the interlayer to form an Fe-Ti phase. In the 68.8Ag–26.7Cu–4.5Ti interlayer/ YSZ interface, two reaction layers of Ti, O and Cu, Ti, Fe, O were observed in sequence from the YSZ to the interlayer. One of the major issues in brazing ceramics, to metals has been an appearance of an excessive residual stress in the joint after cooling, as a result of large differences in the coefficients of thermal expansion (CTEs). Ag and Cu have high ductility and can improve this problem, Ti has a high activity, easy to react with the ceramic,thus successful brazing 430 stainless steel and ceramics. The leak rates and strength of SS430/Ag-Cu-Ti +0.3wt.% Al2O3/8YSZ joint which met the leakage rate requirements for vacuum tight components and increased strength. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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