Microstructural characterization of porous materials by two-dimensional X-ray refraction topography

X-ray refraction topography determines the internal surfaces and interfaces of non-metallic porous materials within the range of namometer to micrometer dimensions. The method is based on refraction of X-rays caused by interfaces of microstructures in heterogeneous materials. Generally, it permits a non-destructive full volume characterization of the pore topology. The X-ray refraction scanning technique make possible to visualize integral interface properties up to 10 μm spatial resolution by two-dimensional topographic images. It detects the spatially resolved internal surfaces of both, open and closed pores. Comparison to a certified powder reference of uniform grain size and known packing density reveals a quantitative measure for calibration requirements. An investigation on SiC- and Al2O3-ceramics illustrate the quantitative characterization of the internal surface density, pore sizes and their spatial distribution as well as local porosity fluctuations.