Flake structure

As with chemical etches, developing optimum conversion coatings requires assessment of the microstructure of the steel. Correlations have been found between the microstructure of the substrate material and the nature of the phosphate films formed. Aloru et al. demonstrated that the type of phosphate crystal formed varies with the orientation of the underlying steel crystal lattice [154]. Fig. 32 illustrates the different phosphate crystal morphologies that formed on two heat-treated surfaces. The fine flake structure formed on the tempered martensite surface promotes adhesion more effectively than the knobby protrusions formed on the cold-rolled steel. 

Soy, and Other Legume Proteins Two quite different product types have been constructed by extrusion, high-density flaked structures for meat analogues, and lower density and crispy products for high-protein snacks. The latter uses conditions similar to that of starch-based cereal extrusion to obtain low bulk density in the expanded product the former uses a higher water content in the extruder barrel and lower exit temperatures to obtain a dense material with open pores or even flaked structmes. For these two types of processes, molecular changes in the extruder barrel are not dissimilar. Post-die structuring of the extrudates determines final product properties. 

Recently, the simultaneous application of pressure and elongational shear by extrusion, allows the production of elongated particles, lightly adhered to their neighbours. This produces a remarkably meatlike aligned flake structure (Cheftel et al. 1992). For fine comminutes, the adhesion occurs in the batter itself, and casings are used to form the final product shape. 

Fig. 10.13. Flake structure of montmorillonite (bentonite). (T, tetrahedron O, octahedron)...

The data show that, unlike the initial specimen, the flake structure is heterogeneous. Near the surface of the flake we observe thin (15 nm) layers of a phase that differs in composition from the central part. Increase in the content of Si and decrease of such elements as Fe and Ca is typical for these sections. The content of Si is greatest near the surface of the flake. In this case we observe slow disappearance of silicon from one surface to the center and rapid increase in the narrow (1.5 nm) zone at the other surface of the specimen. The increased content of Fe and Ca is observed on one of the flake surfaces. 

The layered edge structure is immediately visible on some flakes, as seen in Figure 10. Some flakes do however show damaged edges similar to Figure 7, but the extent is limited to the edge and the flat flake structure remains intact and visible. 

The RFL material also has excellent ciystallinity and a more ideal flake structure, with significantly lower edge surface area. However, the RFL sample still contains considerable amounts of catalytically active impurities, thus increasing its reactivity. As expected the sample with the lowest reactivity is the PRFL sample which has a low surface area combined with zero impurities. 

Another group of cast-iron alloys are called Ni-Resist, These materials are related to gray cast iron in that they have high carbon contents (3 percent), with fine graphite flakes distributed throughout the structure. Nickel contents range from 13.5 to 36 percent, and some have 6.5 percent Cu. 

Although development work on shellac in blends with other synthetic resins has been carried out over a period of time, the only current use in the plastics industry is in the manufacture of electrical insulators. At one time electrical insulators and like equipment were fabricated from mica but with increase in both the size and quantity of such equipment shellac was introduced as a binder for mica flake. For commutator work the amount of shellac used is only 3-5% of the mica but in hot moulding Micanite for V-rings, transformer rings etc., more than 10% may be used. The structures after assembly are pressed and cured, typically for two hours at 150-160°C under pressure. 

Exfoliation corrosion is especially prevalent in aluminum alloys. The grain structure of the metal determines whether exfoliation corrosion will occur. In this form of corrosion, degradation propagates below the surface of the metal. Corrosion products in layers below the metal surface cause flaking of the metal. 

Rohren-halter, m. tube (or pipe) holder, tube (or pipe) clamp, -kassie, /. pur ng cassia, -kleuune, /. tube clamp, -kiibler, m. tubular condenser, tube condenser tubular cooler, -libelle, /. spirit level, air level, -lot, n. pipe solder, -manna, /. flake manna, -nudeln, /.pi. macaroni, -ofen, m. tube furnace (for heating tubes liable to explosion) pipe still, -pulver, n. (Expl.) perforated powder, -struktur, /. tubular structure, -substanz, /. (Anat.) medullary substance, -trager, m. tube (or pipe) support, -wachs, n. petroleum ceresin. -werk, n. tubing piping tube mill, -wischer, m. tube brush, -wulst, n. tubular tore, doughnut , -zelle, /. tubular cell, specif. (Bot.) tracheid. 

Particulate composites consist of particles dispersed in a matrix. These particles are divided into two classes, skeletal and flakes. The first one consists of continuous skeletal structures filled with one or more additional materials. Flakes consist generally of flat flakes oriented parallel to each other. These particles may have any... 

The appearance of a flake of clay reflects its internal structure, which is something like an untidy stack of papers (Fig. 14.45). Sheets of tetrahedral silicate units or octahedral units of aluminum or magnesium oxides are separated by layers of water molecules that serve to bind the layers of the flake together. Each flake of clay is surrounded by a double layer of ions that separates the... 

The carbon-based nanofillers are mainly layered graphite, nanotube, and nanofibers. Graphite is an allotrope of carbon, the stmcture of which consists of graphene layers stacked along the c-axis in a staggered array [1], Figure 4.1 shows the layered structure of graphite flakes. 

Figure 2 shows the SEM image of the flake at a magnification of 350 x, as it was mounted on the conductive carbon tape. If there is a polymeric film covering the sample, the SEM will only show the surface topography of the film, not the structure residing below the polymeric film. EDS was conducted on two areas on the sample as indicated in Figure 2. The EDS analysis was conducted in square spot mode, approximately 1 pm by 1 pm in size. The elemental results are shown in Table 2. Based on these data sets it is apparent that the Type A defect is an iron-rich particle. Based on the lack of chromium or nickel the Type A defect is a particle of steel, not stainless steel.

---