Hydraulic cements are our most important building materials. More than 2 billion t/a Ordinary Portland Cement (OPC) are produced world wide. Most of this material is consumed by concrete production and building chemistry formulations. Both are complex systems made from inorganic cement components, aggregates and organic additives. The organic additives yield the ability to minimize the amount of used cements which are produced by a huge input of energy (energy saving and minimization of CO2 emission). The picture above shows the thin section of an OPC clinker. By etching of the surface the clinker minerals are clearly to distinguish. The physical properties of the hardened cement are strongly influenced by the mineralogical composition (phase composition). The interaction of inorganic cement phases and organic molecules are in focus of our investigations. The early hydration behaviour of cementitous formulations are investigated by in-situ XRD analysis. The evolution of the phase content – starting from the clinker phases forming nano scaled hydration products – is recorded time dependend and is evaluated quantitatively. The linking of these results with the data of the calorimetric investigations are the basis of the development of new models of the interaction of organic additives and inorganic cement phases. The characterization of the solid cement stone allows statements with respect to its nano crystalline framework and its directly linked physical properties.
Polymer Cement Interaction
Implementation of biomimetic processes and organisation is the basic principle how to create innovative bone substitution materials. Synthesis of cellular structured materials with hierarchic porosity is intimately connected with the medical requirements on bone constitution materials. The striking advantage of nano scaled microporous calcium phosphates (CaP), which are organized within another macroporous system (Ø 0.1 to 1 mm), is correlated with their excellent resorption properties and accelerated in vivo bone formation.
Phase composition of CaP-powders, CaP-ceramics and hydrated CaP-cements are quantified by the Rietveld refinement of XRD data. The link between mechanical strength and mineralogical phase composition is investigated. Influence of biocompatible additives on the hydration and strength is analysed with a combination of heat flow calorimetry and in-situ XRD at 37°C (body temperature).
Calcium Phosphate Cements
Calcium Carbonate Precursors
The Applied Mineralogy can provided new ideas and strategies for the development and improvement of high performance materials for optical, magnetic and sensoric applications. Focussing on the correlation of atomic arrangement in the crystal structure, chemical variability and physical property an interdisciplinary approach will be done.
The understanding and interpretation of the connection of phase relations, crystal chemical aspects, dopands and resulting physical properties can be very nicely demonstraded in the case of phosphors. Suitable ions, such as Mn, Cr or REE like Eu, Ce or Tb, are chemically stable incorporated in suitable hosts.
In case of BAM (Ba-beta-alumina:Eu) as a blue phosphor the luminescence properties have been optimized. The study of Phase relations and crystal chemistry are important aspects of the mineralogical research.
Digitalization and characterization of the collections of Greek and Roman coins in the various Numismatic Collections at the FAU and providing them in an online database is an important step towards a Virtual Research Environment (VRE), providing input for the Semantic Web reacting to the demand of Open Linked Data.
3D laserscans provide the possibility to study these coins using non-destructive methods in order to trace the craftsmanship of ancient Greek and Roman metalworkers. Virtual sections of these coins provide information which cannot be collected otherwise without completely destroying these precious ancient artefacts.
In addition, a complete image composed by many single BSE (backscattered electron) images reveal possible exsolutions or alloy anomalies.
By mapping these BSE images onto the 3D model of the coin we achieve a unique insight and far more complete picture of these ancient masterpieces from a metallurgical point of view.
Dr. Martin Boß, Kurator Antikensammlung Erlangen,
Prof. Dr. Ing. Marc Stamminger, Lehrstuhl der Informatik 9 (graphische Datenverarbeitung),
Prof. Dr. Matthias Göbbels, Lehrstuhl für Mineralogie,
Andreas Murgan M.A., Antikensammlung Erlangen,
Dipl.-Ing. Christian Abe, Lehrstuhl für Mineralogie.
Kooperationspartner am Forschungsprojekt „NUMiD – Geschichte prägen/Werte bewahren” des Institutes für Geschichtswissenschaft 3 der Heinrich-Heine-Universität Düsseldorf.