Analysis of Heterogeneous Materials With X-Ray Microfluorescence and Microdiffraction

Abstract

The chemistry of heterogeneous materials can be understood only after determining the elements composing the material, the ways in which those elements combine, and the distribution of the resulting phases. The techniques of photon-induced x-ray microfluorescence (XRMF) and x-ray microdiffraction (XRMD) offer several advantages over conventional electron-beam methods for determinations of element and phase distributions. Those advantages include minimal specimen preparation, good element sensitivity, air operation, the capability of wide area coverage, and the availability of sophisticated search/match routines for phase identification. Instruments combining scanning XRMF and XRMD have been described; however, the spatial resolutions for practical analyses were limited to about 30 {mu}m. Recent developments k microbeam laboratory sources and capillary optics have made routine laboratory analysis possible at spatial resolutions less than 30 {mu}m. After delineating the individual phases with XRMF, x-ray diffraction patterns of representative phase regions can be obtained with XRMD for phase identification. We have used a laboratory-based x-ray microprobe with glass capillary optics to produce element maps, some with better than five micrometers resolution. A Rigaku X-ray microdiffractometer was then used to identify inclusions and phase regions. Examples of the complementary uses of these techniques will include specimens from a study of lead chloridemore » Phases, which affect lead volatilization in waste sites, and MgO cements used to stabilize sludge constituents from an industrial waste water treatment plant. 6 refs., 5 figs.« less