Metallic fibers applications

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]. 

The potential applications of NIR OFCD determination of metal ions are numerous. The detection of metal contaminants can be accomplished in real-time by using a portable fiber optical metal sensor (OFMD). Metal probe applications developed in the laboratory can be directly transferred to portable environmental applications with minimal effort. The response time of the NIR probe is comparable to its visible counterparts and is much faster than the traditional methods of metal analysis such as atomic absorption spectroscopy, polarography, and ion chromatography. With the use of OFMD results can be monitored on-site resulting in a significant reduction in labor cost and analysis time. 

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 protonated form of poly(vinyl amine) (PVAm—HC1) has two advantages over many cationic polymers high cationic charge densities are possible and the pendent primary amines have high reactivity. It has been applied in water treatment, paper making, and textiles (qv). The protonated forms modified with low molecular weight aldehydes are useful as fines and filler retention agents and are in use with recycled fibers. As with all new products, unexpected applications, such as in clear antiperspirants, have been found. It is useful in many metal complexation applications (49). 

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

Use of fibers as reinforcements to make composites is, of course, well established. These are structural applications where, because of the characteristically long length of fibers, they are incorporated in a continuous medium, called the matrix. We describe some of these applications in subsequent chapters in more detail. Yet another common use of fibers of various kinds is in making ropes. In prehistoric times, ropes were made of braided leather strips and vines. Later, vegetable fibers such as jute, hemp, etc., were used to make ropes. More recently, ropes have been made of synthetic pol3nmers and metallic fibers. Ropes can be made by a variety of construction methods twisted, braided, plaited, parallel core and fiber, and wire rope. 

An important application field for stainless steel fibers is the textile sector, in which 0., i to 6% of these fibers are incorporated to endow carpets, protective clothing etc. with an antistatic finish. A further application is protection against electromagnetic pulses, interference and charging. Tungsten fibers with a diameter of 12 pm are used for boron or SiC deposition and as light bulb filaments. Furthermore, metal fibers are used in the filtration of polymer melts and corrosive liquids, as well as for electrodes with high surface areas. 

When the mesogen moiety is included into the main chain of the polymer, the obtained macromolecule contains inherently rigid units, which usually result in remarkable mechanical properties and thermal stability. Fibers made by these polymers compete with the best ceramic fibers and are far superior to metal fibers [83]. They therefore are ideal candidates as reinforcements for polymer-based composites. However, these materials often have a poor miscibility and adhesion to other polymeric substrates, limiting the range of their applications. This problem basically arises from weak intermolecular interactions either within the liquid-crystalline polymer itself or with the matrix of the composite. Strong ionic... 

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

Although various electrochromic devices have been demonstrated, their performance still needs to be drastically improved. This will require a major research and development effort. On the other hand, the fiber optic metal hydride hydrogen sensor already shows that metal hydride applications may provide a clear advantage over competing systems. 

Mr. Juras followed up on his discovery. He soon found ways to tailor metal fibers so that when they were condslned with other substances, stronger, better-wearing products could be made. In 1965, he formed his own firm to produce the fibers, and he worked with auto makers and other firms on specific applications. 

Other fibers may be used in POs, though some of these may be chosen more for their special properties. Basalt mineral fibers or Kevlar can provide extreme reinforcement for ballistics applications other fibers include metal fibers for electromagnetic shielding purposes (discussed in Chapter 6). However, as in the case of stainless steel fibers, just because an additive is in fiber form does not necessarily mean it provides meaningful mechanical property reinforcement, but it may provide the opposite of what is wanted [6-4, 7-57]. 

Manual transmissions use a clutch facing made from a resin impregnated wound structure composed of staple yarns, p-Aramid in yam form provides more strength and durability than a pulp-based paper sheet in this more demanding application. Although aramid reinforced facings have sufficient thermal stability for this application, compositions based on glass and metal fibers dominate this market. 

The Lanxide Corporation (now intellectual property within MSE Inc.) have patented the PRIMEXTM pressureless metal infiltration process and the PRIMEX CASTTM foundry process, which are able to infiltrate ceramic reinforcements with molten metals without application of pressure or vacuum and it is believed that the processes can be used with carbon fiber. 

Such glass fiber-reinforced composites based on the unsaturated polyester thermosets are usually fabricated as sheet molding compounds (SMC) and bulk molding compounds (BMC). These are widely used in various metal replacement applications because of their cost-effectiveness, rigidity, light weight, and corrosion resistance properties particularly useful in transportation (cars and trucks), constmction, pipe, and tank applications. Automotive and tmck body panel and strucmral component applications of SMC include doors, hatchbacks, hoods, front grilles, etc. Some nonautomotive applications of SMC and BMC include sanitaryware (bathtubs, shower stalls, sinks), appliances, business machine, and electrical components. 

ABSTRACT. The paper details the use of scanning electron microscopy, surface reflectance infrared spectroscopy, Auger electron spectroscopy, ion scattering spectroscopy, secondary ion mass spectroscopy, and x-ray photoelectron spectroscopy in the analysis of polymeric adhesives and composites. A brief review of the principle of each surface analytical technique will be followed by application of the technique to interfacial adhesion with an emphasis on polymer/metal, fiber/matrix, and composite/composite adhesion. 

The objective of this paper is to present a review of the results of some of the microscopic/spectroscopic techniques which have been used in the study of adhesion. The spectroscopic techniques to be discussed are listed in Table I adapted from Baun (4). A brief review of each technique will be followed by a discussion of results illustrating the application of the technique to polymer/metal, fiber/matrix, and composite/composite adhesion. A recent, more detailed review of the use of surface analytical techniques applied to polymer/metal adhesion has been published (6). 

In summary, there are a number of microscopic/spectroscopic experimental techniques, of which only a limited number have been discussed above, which are readily adaptable to the characterization of polymer/metal, fiber/matrix, and composite/composite adhesion. Indeed, basic questions in adhesion science such as the mechanism of adhesion, bond durability and the composition of failure surfaces, can be addressed experimentally today with increasing confidence due to the availability of these techniques. The author and his associates have summarized (6,11-13,22,25,2634,36-62) the results of the application of surface analysis to polymer/metal, fiber/matrix, and composite/composite adhesion on systems stuped at Virginia Tech. 

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. 

In polymer blend matrix composites, the matrix phase is polymer blend and the reinforcing phase can be metals, fibers, or ceramic particles. They are being used in various medical applications and sensing applications. 

---