PNNL

Abstract

A new ceramic brazing technique referred to as reactive air brazing (RAB) has recently been developed for potential applications in high temperature devices such as gas concentrators, solid oxide fuel cells, gas turbines, and combustion engines. At present, the technique utilizing a silver-copper oxide system is of great interest. The maximum operating temperature of this system is limited by its eutectic temperature of ~945°C, although in practice the operating temperature will need to be lower. An obvious strategy that can be employed to increase the maximum operating temperature of the braze material is to add a higher melting noble alloying element. In this paper, we report the effects of palladium addition on the melting characteristics of the Ag-CuO system and on the wetting properties of the resulting braze with respect to alumina. It was found that the addition of Pd will cause an increase in the melting temperature of the Ag-CuO braze but possibly at a sacrifice of wetting properties depending on composition.