Applications wear resistance

In laptop and desktop computers, internal components need good heat dissipation and static/shock protection. For housings, good aesthetics and mechanical robusmess to drops and impacts are key. Home entertainment and networking are similar to the above. For printers and scanners, moving parts are involved, so for gear applications, wear resistance and lubricity are critical. 

The improvement in wear resistance from ion implantation is shown in Figure 10 (20). However, the thin case cannot sustain very heavy loads. Hence this application for improved wear resistance is limited to special situations, eg, low loads. 

Table 7. Applications of Cobalt-Base Wear-Resistant Alloys...

Excellent toughness and wear resistance. For example, the resistance to cut through of wire coverings is far superior to that of most other heat-resisting plastics. It is interesting to note that in 1994, 50% of applications of PEEK were related to the excellent wear behaviour. 

Both TDI/MOCA and MDI/diol prepolymer systems are of importance for harder grades of printer s rollers and the wear-resisting applications such as pipes, pumps and impellers used in the mining and quarrying industries. 

Jones, R. D. and Jones, D. P., Hot-dip Aluminized Steel Strip for Corrosion Resistant Applications , in Surface Treatment for Corrosion and Wear Resistance, Strafford, Datta and Googen (eds), Ellis Horwood, Chichester (1984)... 

Chromium is also a very hard metal with excellent wear resistance, and so is widely used as a coating material for engineering applications. For these purposes, coatings are applied by electrodeposition which may be several millimetres thick. These hard engineering chromium coatings invariably contain fine cracks and fissures which can allow corrodents to attack the... 

A wide range of applications for hard, wear-resistant coatings of electroless nickel containing silicon carbide particles have been discussed by Weissenberger . The solution is basically for nickel-phosphorus coatings, but contains an addition of 5-15 g/1 silicon carbide. Hiibner and Ostermann have published a comparison between electroless nickel-silicon carbide, electrodeposited nickel-silicon carbide, and hard chromium engineering coatings. 

Even though potential memory exists in all TPs, polyolefins, neoprenes, silicones, and other cross-linkable TPs are example of plastics that can be given memory either by radiation or by chemically curing. Fluorocarbons, however, need no such curing. When this phenomenon of memory is applied to fluorocarbons such as TFE, FEP, ETFE, ECTFE, CITE, and PVF2, interesting high-temperature or wear-resistant applications become possible. 

These characteristics can be further enhanced and their applications widened by fillers, additives, and reinforcements. Compounding properly will yield an almost limitless combination of an increased loadcarrying capacity, a reduced coefficient of friction, improved wear resistance, higher mechanical strengths, improved thermal properties, greater fatigue endurance and creep resistance, excellent dimensional stability and reproducibility, and the like. 

Polyester polyols account for only ca. 10% of the total polyol market, which is dominated by polyether polyols such as hydroxy-terminated polyoxyethylene or polyoxypropylene. Polyester polyols are preferred for applications where better mechanical properties, wear resistance, and UV stability are required. The largest application of polyester polyols is flexible specialty polyurethane foam in the furniture, packaging, and automotive industries. Polyester polyols are also used for nonfoam applications such as coatings, paints, sealants, and adhesives 47... 

The first use of PAs was in fiber applications, in which fibers were produced by melt spinning. These materials have a high strength and good wear resistance and can be easily dyed. The tension stiffening effect of the PA melt made the production of fibers witii homogeneous thickness possible. 

Chemical vapor deposition (C VD) is a versatile process suitable for the manufacturing of coatings, powders, fibers, and monolithic components. With CVD, it is possible to produce most metals, many nonmetallic elements such as carbon and silicon as well as a large number of compounds including carbides, nitrides, oxides, intermetallics, and many others. This technology is now an essential factor in the manufacture of semiconductors and other electronic components, in the coating of tools, bearings, and other wear-resistant parts and in many optical, optoelectronic and corrosion applications. The market for CVD products in the U.S. and abroad is expected to reach several billions dollars by the end of the century. 

Carbides are hard and wear-resistant materials which have a high melting point, are thermally stable, and are generally chemically resistant (although their resistance to oxidation is generally poor). Their composition often varies over a wide range and, as a result, their properties may vary considerably. Some carbides, suchasB4C, SiC, TiC, andWC, are maj or industrial materials with numerous applications.bl... 

The nitrides reviewed here are those which are commonly produced by CVD. They are similar in many respects to the carbides reviewed in Ch. 9. They are hard and wear-resistant and have high melting points and good chemical resistance. They include several of the refractory-metal (interstitial) nitrides and three covalent nitrides those of aluminum, boron, and silicon. Most are important industrial materials and have a number of major applications in cutting and grinding tools, wear surfaces, semiconductors, and others. Their development is proceeding at a rapid pace and CVD is a major factor in their growth. 

CVD titanium nitride (TiN) is the most important interstitial-nitride coating from an application standpoint. It is used extensively to provide wear resistance and as a diffusion barrier and antireflection coating in semiconductor devices. 1 °]... 

CVD coatings are used extensively in applications requiring resistance to wear and corrosion, often over a wide range of temperature. As mentioned in Ch. 1, these coatings and their substrates can be considered as composites which provide unique combinations of properties. 

Coatings of refractory carbides and nitrides and more recently carbon and DLC are used extensively in decorative applications on jewelry, eyeglasses, and similar products in attractive colors such as gold (TiN) and metallic grey, or charcoal (DLC, CrN, and TaN). They provide a surface which is hard and wear resistant, sweat resistant and, in the case of gold, less costly. They are usually applied by cathode sputtering and less frequently by CVD. 

Schintlmeister, W., Wallgram, W., and Kanz, J., Properties, Applications and Manufacture of Wear-resistant Hard Material Coatings for Tools, Thin SolidFilms, (107) 117-127 (1983)... 

In conclusion, one should choose an appropriate multilayer system for different application purposes. For the case of fatigue wear, multilayer films consisting of two hard materials with different shear modulus, such as DLCAVC multilayer film [115], would satisfy the requirement for wear resistance. While for abrasive wear, multilayer films consisting of hard ceramic layers and soft metal layers, such as TiN/Ti and CrN/Cr [116,117] multilayer films are more competent. 

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