Metal fiber

Metal fibers of steel, nickel, tungsten and various alloys constitute, based on their diameters, the transition between fibers and wires. They are generally polycrystalline and are mainly produced by physical working processes. 

Boron fibers are produced by chemical vapor deposition (CVD) onto a substrate filament (e.g. tungsten or carbon) and thereby consist of two components. They exhibit both metallic and nonmetallic properties, which is to be expected for pure boron due to its position in the periodic table. 

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Metallic dyes Metallic fibers Metallic glass Metallic pinwheels Metallic soaps... 

Other fibrous and porous materials used for sound-absorbing treatments include wood, cellulose, and metal fibers foamed gypsum or Pordand cement combined with other materials and sintered metals. Wood fibers can be combined with binders and dame-retardent chemicals. Metal fibers and sintered metals can be manufactured with finely controlled physical properties. They usually are made for appHcations involving severe chemical or physical environments, although some sintered metal materials have found their way into architectural appHcations. Prior to concerns regarding its carcinogenic properties, asbestos fiber had been used extensively in spray-on acoustical treatments. 

For many electronic and electrical appHcations, electrically conductive resias are required. Most polymeric resias exhibit high levels of electrical resistivity. Conductivity can be improved, however, by the judicious use of fillers eg, in epoxy, silver (in either flake or powdered form) is used as a filler. Sometimes other fillers such as copper are also used, but result in reduced efficiency. The popularity of silver is due to the absence of the oxide layer formation, which imparts electrical insulating characteristics. Consequently, metallic fibers such as aluminum are rarely considered for this appHcation. 

For friction material appHcations, composite materials (qv) comprising glass or metallic fibers with other minerals have been developed. In such appHcations also, aramid and graphite fibers are effective, although the cost of these materials restricts their use to heavy duty or high technology appHcations (see Carbon fibers). 

Mesh A metal fiber or other material formed into a woven lattice, used to strain or filter out particulate matter from a fluid or gas. 

Fibers in which the basic chemical units have been formed by chemical synthesis, followed by fiber formation, are called synthetic fibers. Examples include nylon, carbon, boron fibers, organic fibers, ceramic fibers, and metallic fibers. Among all commercially available fibers, Kevlar fibers exhibit high strength and modulus. (Kevlar is a DuPont trademark for poly [p-phenylene diamine terephthalamide].) It is an aromatic polyamide (aramid) in which at least 85% of the... 

But carbon and glass fibers are notable for their fragility and are inconvenient for processing and, therefore metal fibers of brass (Aron Kasei Co.), copper (Toshiba Chemical Corp.) [14], stainless steel (Brunswick Corp., Bekaert) [16], aluminium (MB ASSOCIATES, TRANSMET) [15] have been introduced. 

Sintered metal fibers with filaments of uniform size (2-40 (tm), made of SS, Inconel, or Fecralloy , are fabricated in the form of panels. Gauzes based on thicker wires (100-250 tm) are made from SS, nickel, or copper. They have a low surface area of about 10 m g. Several procedures are used to increase the surface area, for example, leaching procedures, analogous to the production of Ra-Nickel, and electrophoretic deposition of particles or colloid suspensions. The porosity of structures formed from metal fibers range from 70 to 90%. The heat transfer coefficients are high, up to 2 times larger than for random packed beds [67]. 

Fiber-containing cement was initially developed as a high-strength material that could be used to line a borehole [1789]. Several relatively simple and cheap spin-off applications of fiber cement were identified, such as the use of fiber cement in cement plugs for borehole stabilization and as a lost circulation material. Several companies are already applying or offering fiber cement for these purposes in the field, in both organic fibers and metal fibers [372,1077, 1682-1684]. 

Metal Threads. Metal threads, not really metal fibers but metal filaments, are human-made. In antiquity, metal threads were made for ornamental or decorative purposes from precious, ductile metals or alloys, particularly silver and gold and their alloys. Such threads were either applied with adhesives to finished fabrics or wound around ordinary textile yam cores the metal-covered yarn was then either woven into textile fabrics or embroidered on the textile fabric (Jaro and Toth 1991 Lee-Whitmann and Skelton 1984). 

Metallic electrodes, 9 585 Metallic fibers, 24 614, 618 Metallic films, conductive, 9 689 Metallic glasses, 22 576 Metallic gold, 22 701 Metallic halides, ethylene oxide reaction with, 20 638-639... 

In addition to glass fibers, PBT can also be reinforced with carbon fibers. Many of the general trends seen with glass fibers are also observed with carbon fibers. One important aspect of carbon fibers is that they may bring electrical conductivity to PBT if sufficient fiber connectivity is achieved in the final part. Metal fibers and metal-coated carbon fibers have also been compounded with PBT, giving not only improved mechanical properties but also molded parts with enhanced ability to shield components from electromotive and radiofrequency interference (EMI-RFI) [33],... 

ITottinen et al. [44,45] used htanium sintered meshes as DEs on the cathode side of a PEMEC because the porosity of these metal sheets does not reduce when in compression. It was demonstrated that in order ter the cell to achieve the required performance, the sintered meshes had to be coated with platinum. However, the results showed that a cell with CEP (SIGRACET GDEIO-BB) as the DE shll performed slightly better (especially at high current densities) than the cell with the Pt-coated sintered Ti mesh. Cisar et al. [46 presented another example in which a DE consisting of sintered metal fibers was used on the cathode side of a PEMEC. Once put together, these fibers were rmified or bonded to the EE plate (made out of metal) in order to combine the two components into one. 

Caveny, L. H., and Click, R. L, The Influence of Embedded Metal Fibers on Solid Propellant Burning Rate, Journal of Spacecraft and Rockets, Vol. 4, No. 1,... 

Tensile Strength of Inorganic and Metallic Fibers and Whiskers 473... 

Ultimate Tensile Strength of Representative Organic, Inorganic, and Metallic Fibers... 

Attempts have been made to increase the strength of GICs by reinforcing them with metal fibers or flakes. Silver and gold powder have been mixed or fused with the glass powder part of the cement. Such approaches have resulted in improved wear resistance. The properties and clinical use of metal-reinforced glass-ionomer cements have recently been reviewed by Wasson (1993) and hence will not be repeated here [172]. 

Finally, metallic fibers find some limited applications as reinforcement in composites. They are generally not desirable due to their inherently high densities and because they present difficulties in coupling to the matrix. Nonetheless, tungsten fibers are used in metal-matrix composites, as are steel fibers in cement composites. There is increasing interest in shape memory alloy filaments, such as Ti-Ni (Nitanol) for use in piezoelectric composites. We will discuss shape-memory alloys and nonstructural composites in later chapters of the text. 

The electric and heat conductivity of polymers may be increased by the incorporation of conductive fillers, such as aluminum flakes or metallic fibers. 

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