Improving Contour Accuracy and Strength of Reactive Air Brazed (RAB) Ceramic/Metal Joints by Controlling Interface Microstructure

Abstract The development of high‐temperature electrochemical devices such as solid oxide fuel cells, oxygen, and hydrogen separators and gas reformers poses a great challenge in brazing technology of metal/ceramic joints. To maintain the integrity of such equipment, the resulting seals have to be stable and hermetic during continuous and cyclic high temperature operation. As a solution for joining metal and ceramic materials, reactive air brazing has gained increasing interest in recent years. This paper compares joints brazed by different filler alloys: pure Ag, AgCu, and AgAl in three different aspects: contour accuracy, room temperature delamination resistance, and corresponding microstructures of the as‐brazed and fractured brazed joints. Discussion focuses on fracture mechanism and associated delamination resistance. AgAl brazed joints exhibit the most promising mechanical properties and contour accuracy.