Depth Resolved X Ray Fluorescence Analysis of Copper Charged Muscovite Mica

Delamination of muscovite induced by metal cations is a promising way to fine-tune properties of this mica material. For studies of delamination, the ITC-WGT institute has developed a method to intercalate polyvalent metal ions, like Cu, Mg, Zn or Al into muscovite. This paper refers to X-ray fluorescence analysis (XRF) of these samples at ANKA synchrotron radiation facility, Karlsruhe, Germany. At the XRF microprobe elemental distributions of Fe, K and Cu in copper charged platelets were mapped with high spatial resolution. Employing XRF in confocal mode allows distinguishing between Cu ions located at the surface and incorporated into the mica of a 40μm-60μm thick platelet. In order to look for potential exchange processes spatial correlations between Cu and the constituents of muscovite have also been analyzed. First results indicate that in the saturated state the concentration of Cu inside the platelet matches the concentration of the interlayer cation (K). High concentrations of Cu are found at the surface and in cracks in the sample. In order to enhance the depth resolution of the confocal XRF technique the measuring geometry has been varied and it can be demonstrated that the depth resolution can be substantially improved by a proper choice of the angle of incidence.