Magnification materials

When a eutectoid steel is slowly cooled from the austenite range, the ferrite and cementite form in alternate layers of microscopic thickness. Under the microscope at low magnification, the diffraction effects from this mixture of ferrite and cementite give an appearance similar to that of a pearl, hence the material is called peadite. 

Figure 2.13 Small particles of copper embedded in shaft bushing material (shown in Fig. 2.12). (Magnification 55x unetched.)...

Figure 3.6 Tubercle cross section shows black magnetite-rich shell beneath deposit and hematite cap. Note the core material below the magnetite shell. (Magnification 7.5x.) (Courtesy of National Association of Corrosion Engineers, Corrosion 89 Paper No. 197 by H. M. Herro.)...

Figure 3.9 Small tubercle cross section. The steel surface is at the bottom, and the red material is an epoxy mounting medium. Note the small, shallow central cavity. (Magnification 7.5x.)...

Sample preparation methods vary widely. The very first procedure for characterizing any material simply is to look at it using a low-power stereomicroscope often, a material can be characterized or a problem solved at this stage. If examination at this level does not produce an answer, it usually si ests what needs to be done next go to higher magnification mount for FTIR, XRD, or EDS section isolate contaminants and so forth. 

The impact of electron-optical instruments in materials science has been so extreme in recent years that optical microscopy is seen by many young research workers as faintly fuddy-duddy and is used less and less in advanced research this has the unfortunate consequence, adumbrated above, that the beneficial habit of using a wide range of magnifications in examining a material is less and less followed. 

The development of high-magnification microscopy made it possible to create images of biological materials at the molecular level. Many of these images show structures that have liquid crystalline aspects. Shown here are aligned mosaic virus molecules and protein molecules in voluntary muscles. In addition, all cell walls are picket fences of rod-shaped molecules in regular yet fluid arra. ... 

Figure 4. SEM micrographs of the silicalite-alumina composite material A cross-section of the tube. B and C magnifications of the inner surface of the tube and of the first a-AI2O3 layer.

Figure 3 (a) Digital image of the gasket material sample at 7.5 x magnification and (b) digital... 

Based on these preliminary investigations, SEM-EDS was used to identify the particles embedded in the sheets. A particle was isolated from the extruded plastic sheeting and analyzed. Figure 40 shows an SEM micrograph at 14,500 x magnification of the particle studied. This specimen is quite small, on the order of 10 pm in diameter. The EDS results are summarized in Table 11 for both this particle and for the polymeric matrix material from which it was harvested. 

Figure 6.16 Top Electron micrographs of iron-overloaded human spleen (a) and of an avian species (Order passeriformes) (b), showing clumps of densely stained material throughout the tissue, haemosiderin. Bottom Electron micrographs of siderosomes from (a) human spleen and (b) an avian species (Order passeriformes). Iron-rich particles can be seen within the membrane-bound structure. Hexagonal arrangements and clusters of unbound ferritin are also seen. Unstained, magnification x 120000. Reprinted from Ward etal., 2000. Copyright (2000), with permission from Elsevier Science.

Characteristic for a fractal structure is self-similarity. Similar to the mentioned pores that cover all magnitudes , the general fractal is characterized by the property that typical structuring elements are re-discovered on each scale of magnification. Thus neither the surface of a surface fractal nor volume or surface of a mass fractal can be specified absolutely. We thus leave the application-oriented fundament of materials science. A so-called fractal dimension D becomes the only absolute global parameter of the material. 

Fig. 3.8 SEM micrographs of a gel synthesized by adding 10wt.% ofTHEOS to a 1.5wt.%. aqueous solution of cationic hydro-xyethylcellulose. The pictures were taken at various magnifications to demonstrate the main features of the material. (Unpublished results, Pictures taken by Dr. C. Abetz).

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