Influence of Filler and Base Material on the Pore Development during Reactive Air Brazing

Innovative technologies such as solid oxide fuel cells for energy generation make high demands on materials that can often be met by embedding ceramic components into metallic structures. A promising and economic method of joining ceramic to metal or to ceramic is reactive air brazing (RAB). A disadvantage of the RAB joints is the high porosity which can lessen the strength of the joint as well as its gas tightness. Different stages of pore development in dependence of filler and base materials could be observed during the brazing process due to the vaporising of the organic binder, the melting process and a reaction between the filler metal and the base material. By adjusting the process parameters the pore formation can be decreased.