In-situ characterization of materials by synchrotron diffraction

H. Ehrenberg, M. Knapp, C. Baehtz

Darmstadt University of Technology, Materials Science, Petersenstr. 23, D-64287 Darmstadt, Germany.

Diffraction methods are appropriate techniques for the characterization of polycrystalline materials, providing information about composition and structural details. A specific challenge in materials science is the investigation of structural changes in materials as response to external variable parameters. In-situ studies under real operation conditions are in the centre of interest, because relaxation phenomena or changes of the environment can falsify observations of processes in materials during application. The use of intensive and high-energetic synchrotron radiation enables considerably improved and qualitatively novel methods for the characterization of materials as part of devices in operation, mainly due to the penetration capability at very short photon wavelengths. Such investigations elucidate underlying processes and, hereby, contribute to understand working principles on one hand. On the other hand, materials degradation due to aging or fatigue can be followed, providing the basis for materials optimization strategies.

Specific set-ups are described as already available or proposed. The actual performances are demonstrated by selected examples. Materials under investigation include cathode materials in rechargeable batteries, PZT as piezoelectric actuators or sensors and solid catalysts. Recent activities in these fields at dedicated facilities are reviewed, added by results from beamline B2 at HASYLAB. Existing capabilities are discussed in the light of future possibilities.

Acknowledgement

The operation of the beamline B2 at HASYLAB in Hamburg, Germany, for the characterization of polycrystalline materials by synchrotron diffraction is supported by BMBF and DESY. Electric fatigue in functional materials is the subject of SFB595, funded by DFG.