Small Angle X-Ray Scattering with Cobalt Radiation for Nanostructure Characterization of Fe-Based Specimen

A laboratory system (NanoSTAR) based on a combination of specially designed X-ray multilayer optics (Göbel Mirrors) with optical bench, pinhole collimators, sample changer and primary beam stop as well as a two dimensional multiwire detector (HI-STAR) was equipped with a sealed cobalt X-ray tube. This solution was chosen because the CoKα has a wavelength close to that of copper but allows to overcome the problem of excessive fluorescence in Fe-samples. Various measurements were performed using this configuration of the NanoSTAR to demonstrate the performance of SAXS using cobalt radiation. A comparison is given to the primary beam intensity of the NanoSTAR with Co radiation with respect to the Cu radiation. Examples for the use of the Co radiation are given by investigating the coarsening behavior of precipitates in several Fe-based alloys. The change in size and shape of these precipitates under different heat treatment conditions are characterized.