ELECTRON MICROSCOPY MODERN SURFACE, LAYER AND DEFECT ANALYSIS USING REM, FIB, EDX, STEM

Transcription

1 FRAUNHOFER INSTITUTE FOR MANUFACTURING ENGINEERING AND AUTOMATION IPA ELECTRON MICROSCOPY MODERN SURFACE, LAYER AND DEFECT ANALYSIS USING REM, FIB, EDX, STEM 1

2 METHOD Electron microscopy is the favourable solution for the detailed, high-resolution study of small particles and thin layers within coating structures. Microscopic investigations down to the nanometer scale include the techniques of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Information about the chemical composition in the micrometer scale of the samples can be obtained via local energy-dispersive X-ray spectroscopy (EDX). Further, a focused ion beam (FIB) enables the selective preparation of targeted cross-sections and thin TEM lamellae in the micrometer range. At the department of Coating Systems and Painting Technology, a Dual-Beam scanning electron microscope of the type Helios NanoLab600i is available, including an integrated focused beam and energy dispersive X-ray analysis. The most relevant applications are Surface analysis General surface structure Elemental composition (EDX) Layer analysis Layer structure (cross-section, FIB) Elemental composition of the layers (EDX) Damage and defect analysis Morphology of defects Defect dissection (FIB) Elemental analysis (EDX) 2

3 HIGHEST IMAGE QUALITY FOR COATINGS AND PIGMENTS DOWN TO THE NANOMETER SCALE Precise and detailed images even at high magnifications (resolution of 2 nm) are possible using a field emission electron beam. Low acceleration voltages and low beam currents enable to analyze even delicate organic samples. Characterization of pigment structures (with kind permission of M.E.Bohem (Dissertation)). (Source: Fraunhofer IPA) Anodization on Al, layered coating, Ni-foam. (Source: Fraunhofer IPA) 3

4 FOCUSED ION BEAM (FIB) PREPARATION OF CROSS-SECTIONS AND TEM-LAMELLAE The»Dual-Beam«Principle. (Source: Fraunhofer IPA) With the focused ion beam selected spots can be cross-sectioned in situ. For ultra high resolution TEM lamellae can be prepared (e.g. for high resolution EDX). TEM lamellas can also be investigated with the built-in STEM detector (STEM: Scanning Transmission Electron Microscope). These methods provide further defect analysis as well as the evaluation of particle sizes, shape and distributions. Cross-Section of a coated sample. (Source: Fraunhofer IPA) 4

5 ENERGY DISPERSIVE X-RAY ANALYSIS (EDX) ELEMENTAL ANALYSIS AND MAPPING The electrons of the electron beam activate the atoms close to the surface of the sample (collision), which subsequently emit x-ray radiation with element-specific energy. In this way, the element distribution can be locally detected and displayed, with high resolution (mapping). Elemental-Mapping on a cross-section of a steel sheet with a zinc-magnesium coating and a zinc phosphate pretreatment. (Source: Fraunhofer IPA) 5

6 Pforte P Besucher N Allmandring Pfaffen waldring S Universitätsstraße Allmandring IFF Lernweg North Gate Fraunhofer -Gesellschaft Universitätsstraße pedestrian way Car P Allmandring 37 Nobelstraße 12 Main Gate Nobelstraße COATING SYSTEMS AND PAINTING TECHNOLOGY YOUR CONTACT PARTNER FOR IMPROVING PRODUCTIVITY AND QUALITY IN THE ENTIRE PROCESS CHAIN OF COATING TECHNOLOGY Head of Department Dr. Michael Hilt, MBA Phone michael.hilt@ipa.fraunhofer.de Group Manager Applied Coating Technology Dr. Ulrich Christ Phone ulrich.christ@ipa.fraunhofer.de Fraunhofer Institute for Manufacturing Engineering and Automation IPA Departement Coating Systems and Painting Technology Allmandring Stuttgart Director Prof. Dr.-Ing. Thomas Bauernhansl Fraunhofer Institute for Manufacturing Engineering and Automation IPA Nobelstrasse Stuttgart How to reach us: 6