Friction and Wear Performance

Similarly, a substantial decrease in the specific wear rate, w, can be observed in Si02-g-PAAM filled composites with the rise in filler content and all vv values are lower than those of untreated nano-SiOj-filled systems, although the untreated nanoparticles can also result in decreased w, with respect to the unfilled epoxy. Within the filler content range firom 2 to 6 vol.%, the wear resistance of epoxy is increased by a factor of about 20 by the addition of SiOj-g-PAAM. Bearing in mind the fact that 40 wt.% micron-sized SiOj (180 /tm) particles were needed to acquire a significant decrease in the wear rate of epoxy, the present systems are clearly characterized by a broader applicability. 

The modification of nanosilica by means of grafting polymerization helps to impart a balanced performance of the composites. In addition, different grafting monomers result in different interfacial interactions and different ultimate properties of the composites. 

The addition of grafted silica nanoparticles into PP can bring in both reinforcing and toughening effects at rather low filler contents. Such a simultaneous improvement in modulus, strength, and elongation to break is hard to observe in conventional micron-sized particulate composites. 

Grafting polymerization onto nanosilica can also increase the interfacial interaction between the particles and the epoxy matrix through chemical bonding. It proves to be an efficient way to further enhance the effect of the nanoparticles on the improvements of the tribological performance. 

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Erdemir, A., Nilufer, I. B., EryUmaz, O., Beschliesser, L. M., and Fenske, G. R., Friction and Wear Performance of Diamond-like Carbon Films Grown in Various Source Gas Plasmas," Srrr/ Coat. Technol., Vol. 121,1999, pp. 589-593. 

One early report described the friction and wear performance of a high-temperature compact containing molybdenum disulphide, silica, lead oxide, silver and... 

Apart from physical roughness and chemical passivation effects, phase transformation or structural changes can also play a major role in the friction and wear performance of diamond coatings.The extent of such changes may be dominated by environmental species or by ambient temperature. 

Fibers and chips of nonferrous metals and alloys like copper, brass, aluminum, zinc, and bronze are used in friction materials to provide the desired friction and wear performance. Porous and solid metal powders like tin, brass, copper, bronze, and iron are also used in some products. As mentioned earlier, some metal powders are also used as binders in sintered formulations. 

Yousif, B. F. (2008). Frictional and wear performance of polyester composites based on coir fibers. Proc. IMechE, PartJ J. Engineering Tribology 223(1), 51-59. 

The most studied anti-wear material modified by whiskers is PEEK. Wang et al." compared the performances of PEEK before and after modification with potassium titanate whiskers. The friction and wear performances of the latter showed obvious improvement over the former. Under 300 N, the wear resistance of the latter increases 2.64 and 2.11 times than the former, respectively. In addition, calcium carbonate whiskers have an excellent anti-friction effect on PEEK composite material. When the whisker content is less than 15%, the wear rate of the material decreases dramatically. The wear rate of the... 

The combination of nanoparticles and short carbon fibers exhibited a clear improvement in the wear resistance of both thermosetting and thermoplastic composites. In addition, this concept allowed the use of these materials under more severe wear conditions, such as higher normal pressures and sliding velocities. A topographic smoothening and a possible rolling effect due to the nanoparticles are supposed to be the reasons for this progress in the friction and wear performance. 

In all conditions, the organo molybdenum additive (MoDTP) gave optimum friction and wear performance. 

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