Chemical microdomain analysis of surfaces by X-ray spectroscopy: EDX / WDX / EPMA

Electron beam microprobe SX100.
© Fraunhofer IST
Electron beam microprobe SX100.

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).
© Fraunhofer IST
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

EMPA Ni mapping.
© Fraunhofer IST

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

comparison of measurements using EPMA and an independent RBS (Rutherford backscattering spectroscopy) measurement
© Fraunhofer IST

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.

Further information


Fraunhofer IST in the journals


Kirsten Ingolf Schiffmann, Cornelia Steinberg

EPMA-Analyse dünner PVD- und CVD-Schichten – Grundlagen und Beispiele aus der industriellen Praxis (German)

In: Vakuum in Forschung un Praxis, June 2019, Vol. 31, No. 3, pp. 26-36




From research

EPMA-Analysis of thin coatings

The chemical composition and thickness of thin coatings are often the most important parameters determining the function of a film. Quality assurance of these parameters is therefore essential, during both development and production.