Reactive air brazing as joining technology for SOFC

Reactive air brazing (RAB) is a promising technology to join metals and ceramics in air. RAB brazes in the Ag-CuO-system can be used to seal electrochemical devices like solid oxide fuel cells (SOFC). The present study focuses on the development of interfacial layers between RAB brazes and the metallic component of metalceramic-joints during thermal treatment at high temperatures. Special interest is paid on the CuO content of the RAB brazes and the type of the metallic alloy. It can be shown that certain components of the alloys and also the content of the active CuO phase in the RAB braze are responsible for the evaluation of the microstructure at the interfaces. Independent of the amount of CuO in the braze, samples brazed with the Mn containing Crofer 22 APU showed thicker oxide reaction layers at the interface than the ones with ITM-LC. The influence of the CuO content in the RAB braze on the long-term stability is also discussed.