Post stack dissection

Lessons Learned from Post-Test Stack Dissection and Analysis 488 Conclusion and Outlook 489 Acknowledgments 490 References 491... 

Unfortunately, up to now only limited information has been pubhshed about post-test analysis, methods, and results, and this is trae of our own research center in addition to any other developer, be it companies or R D centers [1-4]. Only single effects after stack operation, single-cell testing, or model experiments and theoretical considerations have been published, such as metal corrosion, Cr poisoning, and thermodynamics [5-15]. Therefore, this chapter summarizes for the first time the stack dissection method, the underlying reasons for stack post-test analysis, the individual characterization techniques and methods, and the results obtained so far. 

The quality and reproducibility of the materials and processes used are ensured by consecutive numbering of all stack parts (cells, interconnects, frames, glass-ceramic batches), handling instructions for aU processing steps, standardized stack operation, and stack dissection protocols. All information is collected on a central server system. Hence after stack testing, dissection, and post-test analysis, conclusions can be drawn with respect to the materials used, processes, and testing. There is a complete chain from the starting materials to the post-test analysis and this is also necessary to develop the SOFC system for marketability. 

Lessons Learned from Post-Test Stack Dissection and Analysis... 

If a stack is to be analyzed after operation, it is necessary to define in advance which of the above-mentioned reasons are the basis for the post-test characterization or whether the stack is characterized with respect to special questions. On this basis, a first important decision has to be made will the stack be dissected plane-by-plane and subsequently the components characterized individually, or should the stack or stack parts be embedded. In particular, in order to retain the geometry and the contact situation, it might be useful to embed the stack completely or partly in a polymeric resin. After embedding, a water jet is used to cut samples in various positions and at various cutting hnes, and these samples can then be extracted for post-test analysis. If the stack is not to be embedded, it is possible after dissection to extract single samples from the individual parts such as the frame with ceU, the interconnect, or the bottom and top plate by laser cutting for further investigations. 

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