Metallic fibers microstructure

Figure 11.18 Three-level structure of a zeo-lite/sintered metal fiber catalytic bed (a) microstructure of a zeolite film of oriented submicron crystals, (b) mesostructure of...

The fifth block is devoted to metallic fibers and thin wires, relevant in the tyre industry, in electrical and electronic applications as well as in civil engineering. H.U. Kiinzi deals with the influence of fabrication processes and microstructure on the strength and fracture of metallic filaments, and K. Yoshida analyzes the influence of internal defects during the drawing of these metallic wires. 

Further SEM analysis on the TCON A foam, showed that the infiltration was due to cracks or holes in the spherical particles. TCON B was created using a fiber material and AUOj spheres immersed in pure aluminum metal. The microstructure of TCON B can be seen in Figure 3. 

The required degree of understanding of the physical properties of metal thin films used for interconnects on chips is illustrated by the following example. It was found that the performance of conductors on chips, A1 or Cu, depends on the structure of the conductor metal. For example, Vaidya and Sinha (10) reported that the measured median time to failure (MTF) of Al-0.5% Cu thin films is a function of three microstructural variables (attributes) median grain size, statistical variance (cr ) of the grain size distribution, and degree of [111] fiber texture in the film. 

In recent years, activated carbons fibers (ACFs) because of their high surface area, microporous character, and the chemical nature of their surface have been considered potential adsorbents for the removal of heavy metals from industrial wastewater [1 3]. The properties of ACFs are determined by their microstructure, it is therefore important to investigate the microstructure of ACFs in terms of specific surface area, micropore volume, pore size distributions, surface chemistry and so on. Also, the adsorption properties of carbonaceous adsorbents are dependent on not only the porous structure but also the surface chemistry [3,4]. 

The production of carbon fibers or filaments by decomposing a hydrocarbon gas over a transition metal catalyst has been the subject of extensive research. The product consists of filaments with diameters in the range of 1-100 pm and lengths up to 100 mm. In microstructure, it is different from traditional carbon fibers, resulting in a sword and sheath fracture mode without catastrophic failure. Since, in addition, these fibers are produced in a single step with no really expensive processing, they are attractive candidates for reinforcing composites. 

In recent years simultaneous progress in the understanding and engineering of block copolymer microstructures and the development of new templating strategies that make use of sol-gel and controlled crystalHzation processes have led to a quick advancement in the controlled preparation of nanoparticles and mesoporous structures. It has become possible to prepare nanoparticles of various shapes (sphere, fiber, sheet) and composition (metal, semiconductor, ceramic) with narrow size distribution. In addition mesoporous materials with different pore shapes (sphere, cyHndrical, slit) and narrow pore size distributions can be obtained. Future developments will focus on applications of these structures in the fields of catalysis and separation techniques. For this purpose either the cast materials themselves are already functional (e.g., Ti02) or the materials are further functionalized by surface modification. 

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