SEM-EDAX

The alternative approach to detection and analysis incorporates a solid state detector and a multichannel pulse height analysis system. The crystals used are of silicon (of the highly pure intrinsic type), or the lithium drift principle (p. 463 etseq.) is utilized. All emitted radiations are presented to the detector simultaneously and a spectrum is generated from an electronic analysis of the mixture of voltage pulses produced. Chapter 10 contains a more detailed account of pulse height analysis and solid state detectors. Production of an X-ray spectrum in this way is sometimes known as energy dispersive analysis ofX-rays (EDAX) and where an electron microscope is employed as SEM-EDAX. 

Bolton, A.J., Dinwoodie, J.M. and Davies, D.A. (1988). The validity of the use of SEM/EDAX as a tool for the detection of UE resin penetration into wood cell walls in particleboard. Wood Science and Technology, 22(4), 345-356. 

Fig. 2. SEM backscattered electron image of a Type II vein containing euhedral to cataclastically brecciated arsenopyrite (asp), pyrite (py), quartz, and calcite. A thin Type 1 quartz vein showed a SEM-EDAX analysis of a very fine-grained mineral mass rich in Hg-Au-As vein (arrow).

Analytical. Silicon analyses of deactivated catalysts were made on cross-sectioned samples with SEM-EDAX. 

SEM-EDAX examination of cross-sectioned samples taken from the pilot plant test at 30, 60 and 80 hours show the presence of silicon. This is indicated in the photomicrographs in Figure 7. 

Figure 7. SEM-EDAX Analysis of Pilot Plant Samples Silicon. Top left, 30 hours top right, 60 hours and bottom, 80 hours.

Figure 9. SEM-EDAX Analysis of Steam-Deactivated Samples Silicon.

Source of Silica. Silica can migrate either from free silica present in the cracking catalyst or from the silica alumina matrix but not as readily from the zeolite. Figure 11 shows SEM-EDAX silicon scans of cerium/alumina steamed in the presence of these three sources of silica. Again, the bright dots represent silicon. Qualitatively the sample steamed with pure silica contains more silicon than the sample steamed with silica-alumina. The sample steamed with zeolite shows silicon at the surface of the cross-sectioned particle but little in the interior. The surface silicon comes from dusting of the particle with very finely divided zeolite. 

Figure 11. SEM-EDAX Analysis of Cerium/Alumina Silicon. Top left, pure silica top right, silica alumina and bottom, molecular sieve.

From SEM-EDAX analysis it is revealed that in the sample doped with Pb-Co (1-7) (0.3)22(2.91) (0.99) , sintered for 144h at 850°C, the 2223 phase has a chemical formula of Bii.7Pbo.3Sr2Ca2(Cui.xCox)30y, where x=0.050. 

The chemical stoichiometric formula of the 2223 phase determined by SEM-EDAX has approached to a theoretical one. 

Biomineralization of cartilage. Prior to mineralization, mitochondria in the chondrocytes, cells equivalent to osteocytes, buried in the protein-glycosamino-gel, load up with calcium and phosphorus. Using SEM/EDAX analyses and microdissection, a timed efflux of calcium and... 

The ammonium salt of Rh(III) Anderson type heteropolymolybdate [RhMo6024H6] has been prepared and characterized by powder X-ray diffraction, spectroscopic [FTIR-Raman, DRS (UV-visible)] and SEM-EDAX electron microscopy techniques. The water soluble salts were used in the design and preparation of Y-AI2O3 supported catalysts. The varied Mo Rh ratio of both olution and solid samples was measured by AAS technique. The supported oxidic system was characterized by DRS spectroscopy and SEM-EDAX microscopy. The HDS and HYD activity for different bimetallic catalysts was measured in a high-pressure reactor. In addition, some conventional catalysts and some C0M06 and combined supported systems [(RhMoe + AIM06)] have been tested for comparative purposes. The discussion about the performance of the new catalysts is made on the basis of the structural and physicochemical heteropolyanion properties as well as the preparation conditions. 

Crystallization phenomena of a series of the molecular sieves MeAPO/j-5 and MeASPO-5 have been studied under the influence of different Me-components. As Me components Be, Mg, Zn, Ni and Fe have been used. These components have been offered in some excess to study the extent of the incorporation which was determined by SEM-EDAX at the product crystals. 

As far as possible the incorporation of the ions into the crystal shall be studied by SEM-EDAX experiments. 

The SEM-EDAX experiments have been carried out at a EDAX terminal PV-9900 in connection with a Philips scanning microscope SEM 515/D806. 

Physico-chemical characterizations of the monoliths were performed on the powder of the crushed monoliths (TPR) or directly on the honeycomb substrates opportunely sectioned ((BET, XPS, SEM/EDAX). Details on the characterization techniques are reported elsewhere [4-6]. The experimental apparatus used to perform the catalytic tests is described elsewhere [9]. Before the catalytic tests the samples were pre-treated in situ under flowing O2 (10 vol.% in N2) at 400 °C for 30 min, then cooled to room temperature in nitrogen. CO oxidation only tests were carried out over the two prepared monoliths (mono 1 and 2) by feeding the mixture CO 1750 ppm, O2 10 vol.%, N2 balance. Combined light-off experiments were performed over the Pd-Pt promoted substrate Pd-Pt/mono 2) by feeding the reaction mixture CO 5000 ppm, CH4 400 ppm, O2 1.0 vol.%, N2 balance. In all the experiments, the GHSV was set at a realistic value, i.e. 100,000 h ... 

Any possible influence of the synthetic procedure on the textural properties of the samples was evaluated by SEM/EDAX analyses. In Figs. 4a,b two representative micrographs of the sample mono 1, after four CO oxidation cycles, are displayed. No good thermal stability upon the catalytic ageing was observed in that sample. It seems that the active phase tended to come off, accumulating in thick layers onto the cordierite walls and confirming deep cracks. ... 

Besides basic compoimds, an improved capacity for MM removal can be also obtained by surface impregnation with compounds, which are able to promote redox surfece reaction. It was found that the modification of the activated carbon surface with Fe203, KI and KIO3 (all about 4 wt%) increased the capacity of activated carbon by a iactor 3-5 [134]. On the other hand, the same treatment of activated carbon fibers increased the capac% over 200 times. It is interesting and very unique for the results, which have been reported in the literature that this process led to the deposition of elemental sulfur on the surface, which was confirmed using SEM/EDAX experiments. 

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