Fraunhofer Institute for Surface Engineering and Thin Films IST
Electron beam microprobe SX100.
Chemical microdomain analysis of surfaces by X-ray spectroscopy: EDX / WDX / EPMA
Energy dispersive and wavelength dispersive X-ray spectroscopy (EDX / WDX) for chemical composition determination
The Fraunhofer IST has two scanning electron microscopes with EDX detectors, as well as an electron beam microprobe (EPMA) with 5 WDX detectors. In the field of microanalysis, it can be used to image surfaces with high resolution and perform chemical point analysis with micrometer resolution. Advantages of these methods:
- Qualitative and quantitative chemical element analysis
- All elements (except H, He, Be, Li)
- High lateral and vertical resolution (~ 0.5 µm)
- High absolute accuracy (1 - 3 %)
- Low detection limit of 0.1 ... 0.01 %
- Layer thickness determination possible (< 0.5 ... 1 µm)
Versatile and flexible applications of EDX / WDX / EPMA
The Fraunhofer IST has 30 years of experience in the industrial application of these methods, e.g. for damage analysis, material and coating development, corrosion and adhesion problems, market observation, etc.
- Fast point analysis with micrometer resolution
- 2-dimensional elemental distribution images using electron beam scanning
- Measurement on transverse or oblique sections for depth profiles of the chemical composition
- Automated measurement of large sample series (100 - 500 pieces)
- Simultaneous determination of layer thickness and composition for single and multiple layers < 0.5 - 1 µm
EPMA trace analysis
EPMA linescan over graphitic precipitation in cast iron (left). Cross-section of cast iron with graphitic precipitations (right).
EPMA Linescan over a spherical graphite precipitation in cast iron. Detection of 0.13 wt.% boron enrichment in the particle shell and 0.03 wt.% phosphorus in the particle interior. Detection limit typically 0.01 at%.
Element distribution
Mapping of Ni distribution in a rolled steel sheet over an area of 2x10 mm2. Deviations from the mean Ni content of ± 0.4 weight% are shown.
Thin-film analysis on double-layer system
Non-destructive layer thickness determination and simultaneous characterization of the chemical composition of a NiCr/GdTbFe double layer. Comparing measurements using EPMA and independent RBS (Rutherford Backscattering Spectroscopy) measurement shows the high level of accuracy in layer thickness and composition.