Tribological Property

The term tribology is derived from the Greek XQipo) ( tribo ) meaning I mb . Tribology is the science and technology of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication, and wear 

Review on Tribology ofSintered a-SiC Ceramics It was duringthe early 1980s that the 

Consistently positive practical experience gathered by Knoch et al. on sintered-SiC seal rings [479, 480] has helped the material to gain popularity rapidly for use in situations involving wear problems. 

When Sasaki [496] studied the influence of humidity on friction and wear behavior of SiC/ SiC couples, a humid atmosphere was seen to reduce the coefficient of friction from 0.5 (dry air) to 0.2 (wet air), whilst a simultaneous decrease in the coefficient of 

Kitaoka et al. [503] investigated the effects of temperature and sliding speed on the 

1 Review on Tribology Work in Sintered aSiC Ceramics 

Tribology is the study of adhesion, friction, wear and lubricated behavior of materials in solid state contact. It was in the early 1980s that the advantage of 

Smythe and Richerson [215] conducted experiments in which the dynamic sliding contact behavior at temperatures greater than 1000°C was studied. It was found that surface film formation at higher temperatures governs the friction behavior. It is believed that Si02 or Si02 modified by impurities from the SiC or the environment with flow properties contributed to the lowering of the friction coefficient [216], 

Tomizawa et al. [217] performed pin-on-disk experiments on friction of SSiC against itself in water at room temperature. The authors found a friction coeflBcient of 0.26 and noted that wear of sintered silicon carbide occurs by a combination of tribochemical dissolution and the formation of pits by fracture of SiC grains. The amount of material removal varied from one SiC grain to the other, due to a strong dependence of tribochemical wear on crystallographic orientation of SiC grains. 

Gunmathan et at studied the wear performance of the clay-polyamide hybrid gears produced by melt intercalation and reported that the wear resistance of the nanocomposite gears is excellent and hysteresis heat generation is also low, which may lead to enhanced gear life [110]. 

In general, weak adhesion between the clay platelets and polymer matrix results in the brittle nature of nanocomposites. During frictional contact, the surface layer can be easily removed by the impact of asperities. 

SEBS-g-MA possesses high toughness and hence has a tendency to toughen the clay-polyamide system, resulting in higher wear resistance than other systems. 

Similarly, the transfer film formation during sliding contact affects the tribological behavior of the polymers (Bahadur, 2000). In neat polyamide. 

On the other hand, it seems that upon nanosilica reinforcement, the friction coefficient slightly increases. The variation is irregular with the rise in nanosilica 

It is assumed that the use of such a nanocomposite as a matrix in continuous fiber-reinforced composites will definitely improve the matrix-related properties, such as interlaminar fracture toughness, transverse tensile strength and modulus, as well as interlaminar shear strength. The same should be true for polymer-based tribomaterials, in which such a nanoparticle-modifled resin is used in combination with friction and wear improving fillers, such as short carbon fibers, PTFE particles, and graphite flakes. 

Sreekala wishes to thank the Alexander von Humboldt Foundation for the post-doctoral research fellowship at the Institute for Composite Materials Ltd., University of Kaiserslautern, Germany. Further thanks are due to Prof. K. Friedrich for his valuable comments on the results of this work. 

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Carbon-fibre-filled grades exhibit interesting tribological properties and useful antistatic behaviour. 

Erdemir, A., The Role of Hydrogen in Tribological Properties of Diamond-Like Carbon Films," Surf. Coat. Technol., Vol. 146/147,2001, pp. 292-297. 

Shen, M. W, Study on Eilm-Eorming Mechanisms and Tribological Properties of Lubricating Eilm in the Nanoscale, Tsin-ghua University Ph.D. thesis (directed by S. Z. Wen and J. B. Luo) Beijing, China, 2000. 

No general conclusions on the relations among these parameters can be drawn for the scarcity of better information. Experiments should be designed to measure the tribological properties of TFL for engineering applications. 

Experimental Studies on Tribological Properties of Molecular Films... 

The research work on carbon nitride materials was first motivated due to its hypothetical super-hardness. The tribological properties of the CNx films are, of course, the emphasis of the succeeding research works. Although the expected structure and hardness have not been achieved up to the present, the potential interesting properties still stimulate many approaches on the tribological behavior of CNx films. Figure 8 gives the results of hardness measurement reported by the... 

Though considerable effort has been made on synthesizing yS-C3N4, investigations on the current CNx films did not show unusual tribological properties. However, attempts are still being made to prepare the expected films, not... 

Gangopadhyay, A., Mechanical and Tribological Properties of Amorphous Carbon Films, Tribol. Lett., Vol. 5, 1998, pp. 25-39. 

Czyzniewski, A., Precht, W., Pancielejko, M., Myslinski, P., and Walkowiak, W., Structure, Composition and Tribological Properties of Carbon Nitride Films," Thin Solid Films, Vol. 317, No. 1-2,1998, pp. 384-387. 

Qian, L. M., Tian, R, and Xiao, X. D., Tribological Properties of Self-Assembled Monolayers and Their Substrates Under Various Humid Environments," Tribol. Lett., Vol. 15, No. 3, 2003, pp. 169-176. 

In order to improve the tribological properties of molecular films, molecular surface modification is the first choice to make an approach. A Diblock polymer polystyrene-poly(ethylene)oxide (PS-PEO) thin-films were studied in our previous research because of its interesting structure (one... 

The biggest challenge to produce an ultra-thin (about 1 nm) overcoat is to make the coating free of pin-holes while maintaining the durability and tribological properties. In an HDD system, pin-holes can cause much more contaminants from all sources, such as outgas compounds from polymeric foam components, pressure sensitive adhesives, ionic residues from improperly cleaned components and ambient pollutants, which can be detrimental to the tribology and durability of the HDD. Therefore, efforts have been made mainly on the improvement of carbon film [4-7]. 

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