Physical properties, tribological

The AFM probe tip interacts via various mechanisms with the sample surface, including simple quasi-static and dynamic normal and lateral forces. These (and other) interactions depend on local physical properties of the sample, on the scale of the probed area. Tribological, viscoelastic, and microhardness mechanical properties can be probed under (more or less) controlled environmental conditions. 

Cunha L et al (2010) Ti-Si-C thin films produced by magnetron sputtering correlation between physical properties, mechanical properties and tribological behavior. J Nanosci Nanotechnol 10(4) 2926-2932... 

The most important use of XV is its telomerization with fluoride ion to give a linear hydrofluoroacyl fluoride (XVI), that is fluorinated with elemental fluorine to give a linear perfluorinated polyether (XVIII), which is sold by Daikin as Demnum (Eq 13.18). Note that Demnum and Krytox are isomeric materials. In general, their properties are quite similar, but there are subtle differences in physical properties and in chemical stability in tribological applications. 

Metal-carbon nanocomposite films possessing specific physical properties are recognized to be of current interest for different applications in electronics, mechanics [1-2]. The key property of nanocomposite films is the structure and size of metal particles and carbon matrix [3]. Therefore, the aim of this paper is to study the correlation between the phase composition, structure and tribological properties of Ni/a-C H nanocomposite films formed by microwave plasma-assisted deposition technique as a function of the C2H2 concentration in Ar+C2H2 gas mixtures varying from 0 to 100 %. 

APPROXIMATE MEASUREMENTS OF SOME PHYSICAL PROPERTIES OF CARBON FIBRE REINFORCED POLYMERS, RELEVANT TO THEIR APPLICATIONS IN TRIBOLOGY. 

In the last two decades, polymer nanocomposites have attracted the interest of researchers and industries because of their excellent mechanical, physical and tribological properties. The addition of nanosize inorganic fillers like clay, Al Oj, CaCOj, TiOj, ZnO and SiO has altered the mechanical and physical properties of the polymers significantly, and in general the nanocomposites are superior to virgin polymers in many aspects. 

In this chapter, the methods of producing clay-polymer nanocomposites are discussed in detail. The influence of clay reinforcement on the mechanical, thermal and physical properties of thermoplastic and thermosetting polymers is also discussed. This chapter also comprises of processing techniques of polymer nanocomposites using nanoparticles hke Al O, CaCO, TiO, ZnO and SiO as reinforcements. These materials have the potential to alter tribological, electrical and optical properties considerably. 

The chemical changes observed from XPS results have implications on physical properties such as water contact angle values and tribological properties, especially wear durability. 

Reply bv the Authors Most probably, the transitions in tribological behaviour can be attributed to changes in the chemical and physical properties of the lubricant itself in the contact region and of boundary layers formed by adsorption as well as chemical reactions. As to the lubricant, there is certainly an influence of temperature on viscosity which may lead to a breakdown of partial micro-EHD-films when temperature rises. As to adsorbed layers, they will detach from the surface at a critical temperature. For reaction layers formed by additive-surface-interaction, it is known that threshold temperatures do exist. 

In many cases of traditional tribology, friction and wear are regarded as the results of surface failure of bulk materials, the solid surface has severe wear loss under high load. Therefore, the mechanical properties of bulk material are important in traditional friction and wear. However, in microscale friction and wear, the applied load on the interactional surface is light and the contact area is also under millimeter or even micrometer scale, such as the slider of the magnetic head whose mass is less than 10 mg and the size is in micrometer scale. Under this situation, the physical and chemical properties of the interactional surface are more important than the mechanical properties of bulk material. Figure 1 shows the general differences between macro and micro scale friction and wear. 

The tribological investigation of the chemically bonded PTFE-PA materials shows that besides the low friction coefficients the high wear resistance is the most important property of such products. Examinations with several different PTFE polyamide materials certify this predicate. This phenomenon could be explained by the chemical coupling of the PTFE distributed in PA. The compati-bilisation of PTFE by block copolymer formation causes a better connection to the PA matrix as compared to physical blends. 

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