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New Ionpolisher for high-end surface preparation of composite materials

English title New Ionpolisher for high-end surface preparation of composite materials
Applicant Herwegh-Züger Marco
Number 170738
Funding scheme R'EQUIP
Research institution Institut für Geologie Universität Bern
Institution of higher education University of Berne - BE
Main discipline Geology
Start/End 01.12.2016 - 30.11.2017
Approved amount 55'600.00
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Keywords (4)

high surface quality; 3D; ion polishing; preparation

Lay Summary (German)

Lead
Mit dem Ionen-Poliergerät können Oberflächen präpariert und 3D-Schnitte hergestellt werden. Dies ermöglicht genaue und artefaktfreie Untersuchungen im Mikro- und Submikrometerbereich mit räumlich hochauflösenden Analysemethoden wie der Rasterelektronenmikrocsopie, Atomkraftmikroskopie, Elektronenrückstreudiffraktion oder der Infrarotspektroskopie. Solche Untersuchungen sind notwendig, um die Materialeigenschaften von Festkörpern quantitativ zu charakterisieren.
Lay summary

Inhalt, Ziele und erste Resultate der ersten Projektperiode

Eine artefaktfreie Oberflächenpräparation ist eine grundlegende Voraussetzung für den erfolgreichen Einsatz obengenannter Analysemethoden. Je höher die hierbei notwendige Vergrösserung, umso wichtiger wird dieser Aspekt. Vor allem in Kompositmaterialien mit mechanisch weichen und harten Bestandteilen kommen bis anhin klassisch angewendete mechanische Polierverfahren an ihre Grenzen. Dank dem Einsatz des neu zu beschaffenden Ionen-Poliergerätes können diese Nachteile nicht nur überwunden, sondern auch relativ grosse Flächen im Quadratzentimeterbereich mit einer qualitative sehr hochstehenden Politur versehen werden.

 

Wissenschaftliche und gesellschaftliche Relevanz

Dank der Anschaffung dieser Technik via Requip werden diverse Forschungsprojekte am Institut für Geologie, der Universität Bern und den erdwissenschaftlichen Disziplinen in der Schweiz vom Einsatz des neuen Projektes profitieren können und neue Wege in den Forschungsbereichen von Tonsteinen, Zementen, Gesteinsdeformation, metamorpher Petrologie aber auch der Herstellung von Hochtemperaturdetektoren geladener Teilchen.

Direct link to Lay Summary Last update: 20.11.2016

Responsible applicant and co-applicants

Collaboration

Group / person Country
Types of collaboration
PSI Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
BEFRI Switzerland (Europe)
- Research Infrastructure

Associated projects

Number Title Start Funding scheme
162340 The role of sheet silicate-rich rocks during mountain building processes 01.01.2016 Project funding (Div. I-III)
178785 Fluids and new fluid tracers in water under-saturated continental crust: From rifting to tectonic inversion 01.09.2018 Project funding (Div. I-III)
166280 Tracing the invisible path of fluids in the crust with microscale oxygen isotope measurements in key metamorphic minerals 01.04.2016 Project funding (Div. I-III)
163995 A new infrared spectroscopy laboratory to analyse water in geological materials 01.12.2015 R'EQUIP
149385 Structure and evolution of an antiformal nappe stack (Aar massif, Central Alps): Formation of mechanical anisotropies and their bearing on natural risks 01.10.2013 Project funding (Div. I-III)
164017 Environmental Atomic Force Microscope 01.03.2016 R'EQUIP

Abstract

High quality polished surfaces of solid-state materials are of great importance for the artifact-free observation of microstructures at high resolution and the accurate analysis of the chemical composition of the phases. In the past decades a series of versatile instruments (e.g. FEG-SEM, EBSD, EDS, AFM, etc.) was developed allowing investigations of structural and chemical information at high spatial resolution. Given the composite character of many solid-state materials to be studied (e.g. polymineralic rocks, cement and concrete composites), a high quality preparation of the surfaces to be analysed is key for guaranteeing the analysis of artifact-free surfaces. So far, conventional sample cutting/sawing is followed either by mechanical polishing, chemical etching or a combination of chemico-mechanical polishing (e.g. syton). Despite being successfully applied for dense solid-state materials, these techniques become critical in cases where the composites consist of delicate fine-grained constituents with different mechanical strengths. Particularly clay-rich samples or cement-/concrete-based materials, both with characteristically high porosity, generally show breaking-out of fine-grained minerals and the smearing-in of the break-out products into open pore space preventing a proper surface analysis of the prepared samples. Further problems with conventional preparation techniques are the mechanical destruction of the crystal structure of the upper most nanometers in the case of mechanical polishing and the chemical contamination during etching treatments. To circumvent these problems, in the past decades Focussed Ion Beam techniques were combined with scanning electron microscopy (FIB-SEM). In this way, artifact-free surfaces can be prepared by a scanning ion beam. Despite being versatile, the use of FIB-SEMs is however very cost intensive because of the high purchase and running costs. Most critical is the fact that with this approach surface areas of only few tens of µm2 can be analysed, restricting the database and its statistical significance. A new type of sample preparation, the ion-polishing technique, takes benefit of the artifact free surface preparation by an ion beam. In contrast to the FIB-SEM, ion-polishing is conducted outside an SEM allowing the rotation of the sample. In this way, perfect planar surfaces can be achieved over much larger sample areas (cm2) compared to FIB-SEM, which can then be investigated with diverse analytical instruments (SEM, AFM, EBSD, IR and SIMS). With this approach, artifact-free surfaces can be efficiently prepared without occupying the imaging devices during the time-consuming polishing procedure. Moreover, ion-polishing can perform 3D sectioning thus allowing information on the distribution and interconnectivity of phases in 3D space. In the current proposal we plan to purchase such an ion-polisher, which to our knowledge is the first instrument in Earth Sciences in Switzerland. The access to this versatile instrument at the Institute of Geological Sciences is of great importance for different research teams and innovative projects at the institute, the BeFri department but also in the Faculty of Sciences at Bern University. The running costs will be covered by the institute and the instrument will be open for use in research projects of the Swiss Earth Science community (e.g. SWISS SIMS etc).
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