SEM(scanning elecctron microscopy)
Device designation: JSM 6460
EDX(energy dispersive X-ray), used for the analysis of the chemical configuration (semiquantitative determination)
Device designation: X-Flash Detector 3001
Manufacturer: Bruker AXS
The analytical department of WZR ceramic solutions GmbH, CerCheck®, works with a scanning electron microscope equipped with an energy dispersive X-ray spectrometer. The detector used has a so-called light element window, which also allows the detection of light elements such as oxygen, carbon, fluorine and nitrogen.
Scanning electron microscopy in combination with energy dispersive X-ray analysis (SEM/EDX)
The scanning electron microscopy is a nondestructive imaging procedure, comparable to the light microscopy, but it clearly excels it on many levels.
The electron beams are not subject to the restrictions of visible light and therefore lead to a much higher resolution. Thus, materials can be examined at much higher magnifications (up to 1,000,000 times), depending on the material and application. The excitation of the sample with electron radiation also causes different interactions in the sample and leads to the generation of different radiation. These different radiations are used in scanning electron microscopic analyses. Thus, by means of secondary electrons (SE), topographies, e.g. for the investigation of fracture surfaces, can be analyzed and reproduced three-dimensionally in samples. Back-scattered electrons (BSE) can be used to detect material contrasts. The different material compositions manifest themselves in different grey tones. The regions with high atomic mass appear brighter than the regions with low atomic mass. Characteristic X-rays are generated by the interactions in the sample due to the introduction of electrons. This is detected by an energy dispersive X-ray microanalysis (EDX) and thus allows the analysis of the chemical composition of the sample. The analysis can be performed for individual points, but also for areas (Fig. 3) or lines over a selected area.
Therefore this procedure allows statements about the material state and can provide conclusions on wrong material choice as well as, production and processing mistakes. Nearly all materials can be examined by using the SEM: biological, ceramic and metallic materials. We at the WZR ceramic solutions Ltd have specialized on the investigation and evaluation of ceramic and metallic materials and applications. The samples can be examined as bulk pieces, dispersed samples or as polished sections.
Examples of methods
It is possible to carry out element analysis in detail up to a few µm.
Chosen elements can be determined along selected profiles.
Similar to the illustration of maps it is possible to depict the allocation of elements over the image section. With the defined color assignment a sorted overview on the allocation of elements is possible.
Examples of use
Using the SEM/EDX the following attributes can be analyzed:
- microstructure, composition of the material
- structural changes
- chemical compounding of the material
- impurities, embedding
- porosity, pore distribution
- cracks and their allocation
- modifications of the material influenced by e.g. reactions on temperature
- modifications of the material triggered by reactions with contaminants
- infiltration and accumulation
- corrosion signs
- mechanical stress
- surface and material defects
- construction and processing errors
- evaluation of surfaces