Solid scanning electron micrograph

Figure 8.63, Scanning electron micrographs of the Rh/YSZ catalyst top view (up) and a cross section of the catalyst-solid electrolyte interface (down).67,68 Reprinted from ref. 67 with permission from the Institute for Ionics.

Figure 9. Scanning electron micrograph of base case solid products.

Figure 5. Scanning-electron micrograph of the solid sample drawn off the reaction mixture at the end of the crystallization process from the gel aged for tQ = 5 d tc = 6.5 h, fy = O- B,...

Scanning electron micrographs of alumina powders dispersed in water in the absence and presence of dispersant show that the agglomeration of the solid particles decreases tremendously in the presence of the dispersant. The agglomerates are larger than 10 pm in the absence of dispersant and smaller by more than one order of magnitude in its presence. 

Figure 44 presents a scanning electron micrograph of a capsule in which alumina particles are encapsulated in crosslinked polyacrylamide. Table 20 lists under PLA1 the amounts of the components involved in the preparation of these capsules. The capsules have a polyhedral shape and their sizes are larger (around 5 pm) and more uniform than the polymer latexes free of solid particles. Some of the cells of the gel coalesce during polymerization, forming bulk phases. As a result, some unencapsulated solid particles were also observed. 

Figure 2. Scanning electron micrographs (at three magnifications) of a fire flood emulsion illustrating a case in which, although the water-oil ratio is 2.5 1, water is the dispersed phase. The composition of this emulsion is 63% water, 11% solids, and 26% oil. The compositions of the dispersed and continuous phases were determined from the X-ray signal excited in the electron microscope. The size of the dispersed water phase ranges from less than 0.1 pm up to about 10 pm. The large features labeled O are regions of oil phase that can be described as oil emulsified in a continuous phase of a water-in-oil emulsion. These complex systems are difficult to characterize with anything but microscopic methods.

Figure 2 depicts the variation of Scanning Electron Micrographs with crystallization time at different temperatures. At the beginning of the crystallization, the texture of obtained solid phase can be described as an agglomeration of fibrous (Fig. 2a, 2b, 2d). The 110 and 200 reflections are not present in the XRD pattern at this moment. When those reflections appear, the morphology characteristic of MCM-41 described by Tanev et al [6] or Elder et al [12] is detected (Fig,2e, 2f, 2h, 2j). Crystals have variable size and form and very porous surface. Finally when the triphasic mixture composed of hexagonal MCM-41, lamellar MCM-50 and amorphous phase is detected (Fig. 2i, 2k, 21), crystals with a sandy-rose like structure and spheric grains are clearly observed. The sandy-rose crystals belong to the MCM-50 lamellar structure [13] and the spheric grains correspond to the amorphous silica phase. The presence of MCM-50 and amorphous silica is proved by XRD patterns.

Figure 2 Scanning electron micrograph of the top layer of a sintered body prepared by stabilized suspension with 5 vol% solid concentration.

Fig. 2 shows scanning electron micrograph (SEM) of the top layer of a sintered body prepared by stabilized suspension with 5 vol% solid content. Hereby the homogeneous distribution of pores with d 1 gm can be observed. This range of pore size can be used for the UF filtration applications. The SEM pictures at five different positions across the thickness have been shown in Fig. 3. These pictures indicate a clear pore-gradient structure.

The optical and scanning electron micrographs presented in this chapter show that the particle size of solid materials, such as polymers, monomers, and intermediate chemicals, can be altered by precipitation from a supercritical fluid solution. The only requirement for carrying out the SCF particle reduction process is that the compound must exhibit some solubility in a supercritical fluid. Because the pressure reduction rates are so rapid during the expansion of the solution, supersaturation ratios can be achieved that are much, much greater than can be achieved by thermal, chemical, or antisolvent precipitation processes. Furthermore, it is conjectured that such rapid nucleation rates can result in the particle formation of some materials with a size distribution or morphology that cannot now be achieved by any other process. 

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