PNNL

Abstract

Coal is potentially an inexpensive source of clean hydrogen fuel for use in fuel cells, turbines, and various process applications. To realize its potential however, efficient, low-cost gas separation systems are needed to provide high purity oxygen that will enhance the coal gasification reaction and to extract hydrogen from the resulting gas product stream. Several types of inorganic membranes are being developed for hydrogen or oxygen separation, including porous alumina, transition metal oxide perovskites, and zirconia. One of the key challenges in developing solid-state membrane based gas separation systems is in hermetically joining the membrane to the metallic gas manifold system. To address this issue a new metal-ceramic joining concept referred to as air brazing has been developed. This paper reviews recent progress in understanding the underlying mechanisms responsible for wettting between these novel filler metals and ceramic substrates.