Analytical Tests and Observations (EAO)

The EAO platform is part of the Materials and Processes CERI.

The EAO cluster has several instruments for physicochemical analysis and observations at the micrometre and nanometre-scale.

The EAO cluster’s equipment includes:

• Two X-ray diffractometers:
  D2 PHASER-BRUKER DIFFRACTOMETER
  D8 ADVANCE-BRUKER DIFFRACTOMETER

Analysis: This technique is used to identify crystalline phases.

Principle: The technique consists in sending an X-ray beam at different angles of incidence into the material being studied by positioning a receiver at a 180° incidence angle (Figure 1) in order to recover the diffraction signal. The crystalline material diffracts the received beam at certain angles which are typical of its crystallography (Bragg’s law). At these specific angles, the receiver positioned at the angle receives a more intense beam than when there is no diffraction. This makes it possible to identify the angles.

Materials: Diffractometer analysis can only be performed on crystalline materials. The following materials have been characterised at IMT Nord Europe:

• • • Residual powder from cryogenic production
    • Sediments
    • Cement
    • Polluted soil

• X-ray fluorescence spectrometer:
  BRUKER S4 Pioneer  

Analysis: This technique enables the semi-quantitative analysis of chemical elements from beryllium to uranium. It can be used to identify crystalline phases when analysing test results with the diffractometer.

Principle: X-ray fluorescence spectrometer analysis is based on the following principle: the material exposed to X-ray radiation (electrical source) will itself emit X-ray radiation characteristic of the chemical composing it (Moseley law). The quantity of the element is calculated in relation to the intensity of the radiation received.

Materials: to prepare the sample, the material must be in powder form and is then compacted to form a pellet. The following materials have been characterised at IMT Nord Europe:

• • • Hydraulic binders
    • Sediments
    • Polluted soil

• Two Scanning Electron Microscopes:
  JEOL SEM
  SEM-EDS 4300 HITACHI (Figure 2)

Analysis: The SEM technique is used to conduct several physicochemical analyses:
Produce topographic images of surfaces to observe the relief of a sample.
Obtain chemical images by phase contrast. Light elements are dark and heavy elements are bright.
Perform qualitative, semi-quantitative and quantitative analyses. Determination of the elements present and calculation of their concentration (%).
The JEOL SEM can produce topographic and chemical images with micrometre precision.
In addition to producing topographic and chemical images, the HITACHI SEM-EDS 4300 performs qualitative, semi-quantitative and quantitative analyses of chemical elements. These analyses can be conducted with a nanometre precision. The HITACHI SEM-EDS 4300 can also perform an indentation test to characterise the mechanical properties of heterogeneous microstructures and interfaces with micrometre precision. This technique consists in using a force sensor to control the movement of an indent which penetrates the material and leaves leaves an imprint whose size is characteristic of the material’s mechanical properties.

Principle: The SEM technique is based on electron-matter interactions. An electron beam scans the sample’s surface. The material then emits several types of radiation:

• • • Backscattered electrons (chemical images by phase contrast),
    • Secondary electrons (topographic images),
    • Photon X (qualitative, semi-quantitative and quantitative analysis of chemical elements),

Based on the analysis, the corresponding radiation is detected and processed to obtain the requested information.

Materials: IMT Nord Europe has considerable expertise in characterising waste in cementitious materials. The following materials have been characterised using this technique:

• • • Mortar containing incinerator bottom ash,
    • Waste-based aerated concrete,
    • Furnace slag.