Effect on tribological performance

M. Z. Rong, M. Q. Zhang, G. Shi, Q. L. Ji, B. Wetzel, K. Friedrich (2003) Graft polymerization onto inorganic nanoparticles and its effect on tribological performance improvement of polymer composites, Tribol. Int. 36, 697. 

It is worth noting that tribochemical reactions are not bound to result in positive effects on tribological performance. When PTFE powder and nano-SiC particles were jointly incorporated into PEEK, for instance, the friction reduction and wear resistance capacities of the nanocomposites became worse. The reason for this was the chemical reaction between the nanometer SiC and PTFE during the sliding friction process. The formation of SiFx by consuming a certain amount of nano-SiC and PTFE deteriorated the property of transfer film. Only when the content of PTFE was high enough, the ternary composites nano-SiC/PTFE/PEEK exhibit lower frictional coefficient than the binary ones PTFE/ PEEK. 

In summary, impressive progress has been achieved to understand the role of adsorbed layers in boundary lubrication, but the effect of molecular orientation on tribology performance and the shear strength of adsorbed monolayers are the issues that remain to be clarihed in a long future study of boundary lubrication. 

B. Yousif, and N. El-Tayeb, The effect of oil palm fibers as reinforcement on tribological performance of polyester composite. Surf. Rev. Lett. 14(6), 1095-1102 (2007). 

R. Schledjewski and K, Friedrich, Orientation Effects on the Thermal, Mechanical and Tribological Performance of Neat, Reinforced and Blended LCP, in Oriented Polymer Materials (ed. E Sokyo), Hiittig Wepf Verlag, Zug, 1996, Chap. 17. 

Weng LJ, Liu XQ, Liang YM et al (2007) Effect of tetraalkylphosphonium based ionic liquids as lubricants on the tribological performance of a steel-on-steel system. Tribol Lett 26 11-17... 

Zhang, MQ, Rong, MZ, Yu, SL, Wetzel, B. 2002. Klaus Friendrich, effect of particle surface treatment on the tribological performance of epoxy based nanocomposites. Wear 253 1086-1093. 

Simnazcelik, T. and Ydmaz, T. (2007). Thermal aging effects on mechanical and tribological performance of PEEK and short fiber reinforced PEEK composites. Materials Design 28, 641 -648. 

MORI, A., TANAKA, K. and MORI, H., "Effects of Fluid Inertia Forces on the Performance of a Plane Inclined Sector Pad for an Annular Thrust Bearing Under Laminar Condition", Trans. ASME, Journal of Tribology, Vol. 107, No. 1, 1985, 46-52. 

Neale, M. J., ed. 1995. Tribology Handbook, 2nd ed. Oxford, U.K. Butterworth-Heinemann. This work is very applications-directed and touches only marginally on theory. Performance characteristics are primary in presentation. Various types of bearings, drives, seals, lubricants and lubrication systems are addressed as well and failures, environmental effects, and maintenance and repair. 

A study of the effect of the contact pressure on the Mction-reducing properties was performed with a concentration of 0.1 wt % (Figure 3.17). In a way similar to the other nanoparticles studied, the friction coefficient decreases with the contact pressure. A critical pressure of 1.42 GPa is highlighted, a pressure at which the friction coefficient becomes lower (0.06). A comparison of the tribological performances of carbon onions containing a diamond core and without a diamond core indicates a similar behaviour for the two samples (Figure 3.17). Quite similar friction coefficients are obtained with the two samples for each contact pressure studied. 

The comparison of the tribological performances of these two samples proves the necessity to eliminate iron catalytic particles of nanotubes samples. Indeed, contrary to nickel catalytic particles, which have a benefit effect on the tribological properties of single-walled nanotubes, iron catalytic particles seem to be less effective. To complete this study, it would be interesting to test multiwalled nanotubes containing Ni nanoparticles. 

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. 

---