Microstructure of surface

Kapitza H G 1996 Confocal laser scanning microscopy for optical measurement of the microstructure of surfaces and layers Tech. Mess. 63 136-41... 

S. Tolansky, Microstructures of Surfaces using Interferometry, Arnold, London, 1968. 

S. Tolansky, Microstructures of Surfaces using Interferometry, Arnold, London, 1968 Multiple-beam Interference Microscopy of Metals, Academic Press, New York, 1970. 

Figure 2. Bright-field TEM images showing (a,b,c ) microstructures of surface layer and (cl) that determined at the distance of 0.1mm from the surface a, b- Armco Fe treated by FT and FN processes at 773K during 60 min respectively c,d - Fe+0.7wt.%Ti treated by FN process at 823K during 60 min. Inserts present SAED pattern.

T. Haisch, E. Mittemeijer, J.W. Schultze, Electrochemical machining of the steel IOOC16 in aqueous NaCl andNaNOa solutions microstructure of surface films formed by carbides, Electrochim. Acta 47 (1-2) (2001) 235. 

Figure 5.9 Microstructure of surface layer for Hastelloy N and HN80MTY (enlargement x 100) specimens after 250 h exposure without loading in Li,Be,U/F fuel salt for U(IV)/U(ni) ratios 30 and 60 (at 760°C) as well as 90 (at 800°C).

Material parameters defined by Equations (1.11) and (1.12) arise from anisotropy (i.e. direction dependency) of the microstructure of long-chain polymers subjected to liigh shear deformations. Generalized Newtonian constitutive equations cannot predict any normal stress acting along the direction perpendicular to the shearing surface in a viscometric flow. Thus the primary and secondary normal stress coefficients are only used in conjunction with viscoelastic constitutive models. 

Microstructural examinations revealed that the tube was annealed brass. All cracks originated on the internal surface at pit sites. Cracks were fine, branched, and ran through the metal grains (transgranular). Crack density over the specimens examined averaged 40 cracks per linear inch (16 cracks/cm) of surface. 

Examination of the microstructure of the cavitated surface will commonly disclose evidence of deformation such as twins (Neumann hands) in carbon steel and general cold working in other metals (Case History 12.6). Damage from cavitation can be differentiated from attack by a strong mineral acid, which can produce a similar surface appearance, by observing the highly specific areas of attack characteristic of cavitation. Acid attack is typically general in its extent (Case History 12.6). 

Analysis of surface crystallography and microstructure surface cleanliness... 

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. 

A. S. Berensand J. H. Born, The Effect of Surface Microstructure on the Performance of Rotary Shaft Lip Type Oil Seals. Fourth Rubber and Plastics Conference, July 4-7 (1974). 

There is little data available to quantify these factors. The loss of catalyst surface area with high temperatures is well-known (136). One hundred hours of dry heat at 900°C are usually sufficient to reduce alumina surface area from 120 to 40 m2/g. Platinum crystallites can grow from 30 A to 600 A in diameter, and metal surface area declines from 20 m2/g to 1 m2/g. Crystal growth and microstructure changes are thermodynamically favored (137). Alumina can react with copper oxide and nickel oxide to form aluminates, with great loss of surface area and catalytic activity. The loss of metals by carbonyl formation and the loss of ruthenium by oxide formation have been mentioned before. 

Phase transition occurs at a state of thermodynamic equilibrium, inducing a change in the microstructure of atoms. However, corrosion is a typical nonequilibrium phenomenon accompanied by diffusion and reaction processes. We can also observe that this phenomenon is characterized by much larger scales of length than an atomic order (i.e., masses of a lot of atoms), which is obvious if we can see the morphological change in the pitted surface. 

As noted before, thin film lubrication (TFL) is a transition lubrication state between the elastohydrodynamic lubrication (EHL) and the boundary lubrication (BL). It is widely accepted that in addition to piezo-viscous effect and solid elastic deformation, EHL is featured with viscous fluid films and it is based upon a continuum mechanism. Boundary lubrication, however, featured with adsorption films, is either due to physisorption or chemisorption, and it is based on surface physical/chemical properties [14]. It will be of great importance to bridge the gap between EHL and BL regarding the work mechanism and study methods, by considering TFL as a specihc lubrication state. In TFL modeling, the microstructure of the fluids and the surface effects are two major factors to be taken into consideration. 

TFL is an important sub-discipline of nano tribology. TFL in an ultra-thin clearance exists extensively in micro/nano components, integrated circuit (IC), micro-electromechanical system (MEMS), computer hard disks, etc. The impressive developments of these techniques present a challenge to develop a theory of TFL with an ordered structure at nano scale. In TFL modeling, two factors to be addressed are the microstructure of the fluids and the surface effects due to the very small clearance between two solid walls in relative motion [40]. 

Microscopic techniques are extensively used to study the surface morphology of reinforcing fibers. The characterization of microstructure of polymer fibers provides an insight into stmcture-property relationship of the fiber. Microscopy techniques have been employed for the... 

Classical surface and colloid chemistry generally treats systems experimentally in a statistical fashion, with phenomenological theories that are applicable only to building simplified microstructural models. In recent years scientists have learned not only to observe individual atoms or molecules but also to manipulate them with subangstrom precision. The characterization of surfaces and interfaces on nanoscopic and mesoscopic length scales is important both for a basic understanding of colloidal phenomena and for the creation and mastery of a multitude of industrial applications. 

As a result, scale layer was always formed on the smooth surface of reactor wall as well as irregular. Microstructure was blanketed as soon as the surface was coated with a Ti02 scale film. It could be deduced that once scales were formed, the effect of surface geometrical shape would be more important than its microstructure. 

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