Determination of Auger sensitivity factors for Al-rich quasicrystals

We discuss and compare approaches to using Auger data for semi-quantitative determination of surface compositions of Al-based quasicrystals. We have e xamined two quasicrystalline phases: icosahedral Al-Cu-Fe and Al-Pd-Mn. We find that sensitivity factors obtained from pure elemental standards lead t o underestimation of concentrations by as much as a factor of 2.5 for the m inor constituents, Fe and Mn, and to overestimation by as much as a factor of 1.2 for the major constituent, Al. Surprisingly, calibration with a crys talline phase close in composition to the quasicrystal does not necessarily lead to more accurate results. Auger analyses of fractured surfaces, which are then compared to bulk analyses, is the best option for sensitivity fac tor calibration. Even without absolute calibration of sensitivity factors, however, surface analysis is extremely useful for detection of secondary ph ases, and is superior to common bulk analysis methods. (C) 2001 Elsevier Sc ience B.V. All rights reserved.