The characterization of asymmetric alumina membranes by Rutherford backscattering spectrometry

Effective membrane structures often rely on the presence of thin discrimina ting layers that exert selectivity control while maintaining high fluxes. C haracterizing these separating layers is often difficult given the scarcity of analytical tools capable of measuring structural detail below sample su rfaces. We have shown that Rutherford backscattering spectrometry (RBS) is an effective tool for characterizing asymmetric inorganic membranes. The ab ility to accurately measure the thickness and composition of thin metal lay ers using RES offered a means of analyzing composite structures in which me tals are deposited to influence separation or provide strength to the membr ane. This analysis of commercially available alumina membranes by RES quant ified the interpenetration depth of deposited gold layers. RES has also bee n applied to the measurement of sample porosity in Al2O3 membranes using sp ecialized O-16 resonance experiments. The measured porosity of these asymme tric membranes resulting from the resonance measurements was compared to a graphical analysis of scanning electron microscopy images. The results of t his study suggest that RES may offer advantages in a wide range of membrane materials analysis applications. (C) 2000 Elsevier Science B.V. All rights reserved.