Oak Ridge National Laboratory’s x-ray diffraction (XRD) provides information about the arrangement of atoms in top surfaces (typically <50 μm) of materials/samples. These samples can be polycrystalline or single crystal. XRD is a versatile technique that can be used for a multitude of studies: battery charge-discharge, residual stress mapping, crystallographic texture determinations, crystal orientation, process simulation, thermal expansion coefficients, oxidation/reduction kinetics, phase equilibria studies, order/disorder transformations, Rietveld/quantitative analysis, grazing incidence x-ray diffraction for very near surface/coating/thin film interrogations, and/or macro and micro residual stresses in multiphase/composite samples. Materials studied include metals, ceramics, some crystalline polymers, geologic/soils, ceramic composites, metal matrix composites, and thick and thin films.
Samples must be crystalline, solid or powder. Sample size can vary widely depending upon the instrument and information desired. For example, a portable x-ray stress analyzer can examine the surfaces of 1-mm samples up to automobiles and beyond.
ORNL has more than 10 XRD units dedicated to phase identification, residual stress, and crystallographic texture determinations. Varied x-ray sources accommodate different sample requirements for polycrystalline and single-crystal samples. In situ studies can be conducted under varied conditions, including high temperature, mechanical load, electrical load, or gas atmospheres. Parallel-beam optics are available for rough samples, as well as a residual stress mapping capability.
Access to ORNL’s XRDs is available to industry through cooperative research and development agreements (CRADAs), Work For Others, or by U.S. Department of Energy funding.
Name: Thomas R. Watkins
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