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Geomaterial Science

Prof. Dr. Hans-Joachim Kleebe
Prof. Dr. Hans-Joachim Kleebe

Geomaterial Science (Applied Mineralogy) explores formation/processing conditions, composition micro- structure and properties of minerals, rocks and synthesized compounds that reveal a wide variety of industrial use. The research focuses on a comprehensive characterization of the relevant mineral phases or synthetic components, their performance under pressure, temperature, deformation and local chemical composition as well as tailored synthesis experiments for high tech materials.

The team’s exploratory focus is the crystal chemistry of minerals and synthetic compounds, in particular their crystal structure, phase assemblage, deformation behavior and microstructure progression. The microstructure variation has an intrinsic effect on thermo-mechanical and electrical properties of synthetic materials as well as natural minerals, which in turn can be used to reconstruct the mechanical and thermal history of rock during sub- or obduction processes.

A distinctive feature of the Fachgebiet Geomaterial Science and Environmental Mineralogy (of Prof. Weinbruch) at the Institute of Applied GeoSciences is the application of electron microscopy tech-niques fort he detailed micro/nano-structural characterization of solids. Here, transmission electron microscopy TEM in combination with spectroscopic analytical methods like energy dispersive X-Ray spectroscopy (EDS), electron energy loss spectroscopy (EELS) and energy filtered imaging (GIF) are the main tools used for detailed microstructure and defect characterization.

High-resolution imaging of local defects on the atomic scale in addition to chemical analysis with high lateral resolution (down to a few nanometers) is similarly applied to high-performance ceramics, natural minerals, meteorites and corrosion phenomena.

Recent research projects involve topics such as fatigue of ferroelectrics, re-calibration of the clino- pyroxene-garnet geothermometer with respect to varieties in the Fe2+/Fe3+-ratio, formation temperature of meteorites, defect structure in Bixbyite single crystals and transparent ceramics based on the spinel structure.

Future research activities will include investigations on interface structures in polycrystals, high-temperature microstructures and the study of biomaterials based on Hydroxyl Apatite.