Characterization of the adhesion of thin palladium membranes supported on tubular porous ceramics

Thin palladium membranes supported on porous materials, i.e. composite membranes are excellent hydrogen separators and purifiers, and the adhesion of the palladium layer is a key factor for membrane stability. To determine the adhesion of composite palladium membranes, particularly tubular membranes, the methodological studies are quite few in literature. This work employed five methods to characterize the adhesion of typical tubular composite palladium membranes: cross-cut test, thermal-shock test, hydrogen embrittling test, pull-off test and the pressure tolerating test, the first three of which are qualitative and the others are quantitative. These methods except for the thermal-shock test can successfully distinguish the adhesion difference of the tested membrane specimen. It can be concluded that a single method may give biased or wrong results, and only the testing with different methods together can provide all-round information. It was confirmed that the porous support with rougher surface and larger pores favors the adhesion of the palladium membrane.