Backscattered electrons BSE

Four samples were similarly selected for the EPMA experiments. The samples were dried and embedded in polished epoxy cylindrical plugs. Backscattered electron (BSE) images as well as elemental maps of As, Fe and Ni (EDS/WDS) were collected using a JEOL 8600 Superprobe electron microprobe analyzer (Dept, of Geological Sciences, University of Saskatchewan). 

Fig. 6. Element maps of Ce, Nd, and P demonstrating the high REE content of the secondary apatite. The elevated REE concentrations lead to the high contrast of the apatite in the backscattered electron (BSE) image.

In Figure 4.11, the interaction of a high-energy electron beam with materials is represented. The electrons hitting the material surface provoke the emission of electrons from the specimen mainly as backscattered electrons (BSEs) and SEs. SEs are ordinary signals used for the study of the surface morphology of materials. SEs have low kinetic energy, that is, lower than 50 eV. 

Scanning electron micrographs (SEM) were obtained using a JSM 5500 LV (Jeol, Japan) electron microscope. The observations were performed in a secondary electron (SE) and in a backscattering electron (BSE) mode at a low vacuum pressure of 12 kPa. 

From the discussion of ex situ spectroscopic techniques earlier in the chapter it is clear that other products of the interaction between incident beam and the surface can be detected. One of these is backscattered electrons (BSE) which give an image in which heavy elements lead to high backscattering (white areas) and light elements lead to low backscattering (black areas). Thus a very qualitative form of elemental analysis can be performed by BSE detection. 

The number of backscattered electrons (BSE) that are produced from a given atom is proportional to the atomic number. That is, materials composed of heavy atoms will backscatter more electrons, resulting in brighter gray tones in the image relative to less dense materials. Hence, BSE produce an image that is related to material composition, providing both spatial and chemical information. 

Figure 1. Backscattered electron (BSE) images of the morphology of powders processed under shearing mode by reactive mechanical alloying under hydrogen, a) 2Mg-Co mixture milled for 30h using WD=10 mm and BPWR=10 1 and b) Mg-2B (crystalline (c) boron) mixture milled for 5h using WD=5 mm and BPWR=44 1. RPM=60 applied during milling.

Figure 7.24 SEM images in backscattered electron (BSE) mode (a) and cathodolumines cence (CL) mode (b) of an APS hydroxyapatite coating immersed for 7 days in simulated body fluid (EHBSS) (Gotze, Hildebrandt...

Figure 1, Secondary electron image (left) and inverted backscattered electron (BSE, right) image of a polished sample of a bituminous coal (D seam, Colorado), The minerals are black and the maceral epoxy background is light gray in the...

Experiments. The micro structure of the mortar beams is investigated with a Philips XL 30 FEG Scanning Electron Microscope (SEM). For the analysis in the secondary electrons (SE) mode, freshly broken surfaces are prepared. Polished surfaces are analyzed in the backscattered electrons (BSE) mode. The final polishing stage is carried out with a 1 pm diamond paste. In order to render the mortar surface conductive, samples are coated by evaporation with gold prior to the SEM investigation. 

FIGURE 20.6 (a) A backscattering electron (BSE) image of a nanoporous membrane after it was soaked with GNPs. EDX data are shown in the inset of this figure, (b) A plot of absorbance at 490 nm of fluorescein versus time (min) for fluorescein transport through stretched (circle), unstretched (triangle), and an unstretched with no pores (square) PDMS membranes, respectively. (From Jiao, K. et al., J. Membr. Sci., 401, 25, 2012. With permission.)... 

We have thus far reported only to the SE signal as a means of generating an image in the SEM. In fact, several other signals are generated as a result of the interaction of the incident electron beam with the specimen. These include backscattered electrons (BSEs), X-rays, light, heat, specimen current, electron beam induced conductivity, transmitted electrons (if the specimen is thin enough), to name the most commonly used. 

Examinations of the microstructure were carried out on an optical microscope Leica QWin and in the scanning electron microscope SEM XL30, Philips. In order to illustrate microstructures (the phase contrast and crystallographic orientation maps) backscattered electrons (BSE) and diffractions of them (EBSD) in SEM were used. For observations of surface morphology secondary electrons (SE) were used. 

Scanning electron microscope (SEM) systems are ideal for a pictorial representation of morphological features of single layers of multilayered paint samples (particularly those not well contrasted by optical microscopy as the white ones) obtained by the contrast of secondary (SE) and backscattered electrons (BSE). An important advantage of SEM is the ability to analyze even the smallest smears for this purpose the smears are lifted from the underlying material using double-sided adhesive tape transferred to the sample holder (e.g., slide). Twenty micrometers microtome sections of paint cross-sections are recommended. In order to avoid electrical charging the samples have to be carbon coated or transferred into the chamber of a low vacuum system. 

Analysis of the images occurred from the secondary electrons (SEI), backscattered electrons (BSE) and cathode luminescence (CL). 

Backscatter Electron (BSE) Imanins of AIBC GEN4 friction surface... 

Figure 13. Primary (a) and Secondary (b) Backscatter Electron (BSE) Images of wear track in AIBC GEN4 disc sample after friction/wear test.

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