Material characteristics microstructure

Soft ferrites are used for the manufacture of inductor cores (pot cores) for telecommunications, low-power transformers and high-flux transformers such as television line output transformers, and as television tube scanning yokes (Fig. 9.17). The more important material characteristics for these and other applications are now discussed with emphasis on the influence of composition and microstructure. The review paper by A. Broese van Groenou et al. [9] and the monograph by E.C. Snelling [10] are recommended to supplement the discussion. 

Characterization of Cutting Tool Materials fri general, machining of ductile irons is difficult due to their characteristic microstructure... 

The microstructure of a material is responsible for specific material characteristics. It can be set selectively, e.g., by heat treatment. Machining processes, which work near a technologically justifiable load limit, bear the danger of accidental microstructure modification. One prominent example for this is grinding bum. The term grinding bum is used, if in grinding processes a too high thermal mfluence of the microstmcture has taken place, with the result of a microstmcture modification, which shortens component lifetime, in some cases drastically. 

In this section, limits were imposed on the improvement of toughness in ceramics by the incorporation of britde, discontinuous reinforcing phases. Observations indicate that such additions bridge cracks in the regions behind the crack tips. Whiskers act in the same manner as discontinuous reinforcing phases. Bridging models may be used to optimize toughening effects and to allow for the choice and modification of pertinent material characteristics, such as physical properties and microstructure. 

Initial cell voltage drop due to sulfur contamination is temperature dependent and decrease with increasing temperature [24, 54], The extent and nature of cell degradation is dependent on applied ceU materials and microstructural characteristics and thus the phenomenon of degradation cannot be generalized. It is assumed that any kind of sulfur compound has to be removed to a level <1 ppm to ensure long-term performance of the SOFC. 

When the small dimension of the material structure is comparable to the characteristic microstructural size scale, the film is considered to be a micro structurally thin film. Most metallic thin films used in microelectronic devices and magnetic storage media are examples of microstructurally thin films, where the film thickness is substantially greater than atomic or molecular dimensions. Although the film thickness normally includes only a few... 

The strength of a catalyst has a close relationship with its material characteristics and microstructure. Knudson proposed that the crush strength a) of a catalyst is a function of the diameter (d) of the particle and its porosity 0) ... 

Some materials have characteristic microstructures that can be used for confirmation of their presence. For instance, fused magnesia, sintered magnesia, and seawater magnesia are structurally different. Similarly, calcined alumina, tabular alumina, and white fused and brown fused alumina all have very different characteristics. 

Modulation Spectroscopy has proven to be an important characterization method for semiconductors and semiconductor microstructures. The rich spectra contain a wealth of information about relevant materials, surfaces and interfrces, as well as device characteristics. In general, the apparatus is relatively simple, compact (except EBER), inexpensive (except EBER), and easy to use. One of the main advantages of Modulation Spectroscopy is its ability to perform relevant measurements at room... 

Pitting caused by the dissolution of non-metallic inclusions can increase the value. Consequently, the microstructures of specimens with a high value must be examined to identify the source of the elevated value. In general, P values below 0-10 are characteristic of unsensitised microstructures, while sensitisation is indicated if P, exceeds 0-4. Single loop tests are sensitive to mild degrees of sensitisation but do not readily distinguish between medium and severely sensitised materials. 

Compared with laboratory fixed-bed reactors or conventional extruded monoliths, such a microstructured monolith is smaller in characteristic dimensions, lower in pressure loss by optimized fluid guiding and constructed from the catalytic material solely [3]. The latter aspect also leads to enhanced heat distribution within the micro channels, giving more uniform temperature profiles. 

Successful development of such systems will lead to foamed materials having useful stress-absorbing characteristics in addition to controlled physics properties. Although our work in this area is currently in a very early stage, prototype materials have been successfully synthesized and assessed structurally using three-dimensional (3D) X-ray microtomography. The technique offers a unique insight into the internal microstructure of cellular materials (see Fig. 3). The diameter of the mainly open cell pores varies from approximately 100 to 250 pm (the resolution of the instrument is 5 pm), with cell walls of variable thickness. 

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