Mechanical and Tribological Properties

Only few reports concerning mechanical and tribological data are available so far. Therefore these properties are a main topic of this chapter. Because of the relatively small thicknesses ( 1 pm) of cBN films which can be reached with good adhesion, it is difficult to determine reliable data of hardness. Young s modulus, and wear. 

Knoop hardness values of about 50 GPa for cBN and 25 GPa for amorphous BN (aBN) films were reported by Murakawa et al. [72]. From nanometer indentation measurements hardness H) and Young s modulus ( ) were derived for different sputter deposited cBN films (thickness some 100 nm) [54,55,73]. The hardness values ranged between 60 and 80 GPa which is close to the bulk hardness of cBN (up to 90 GPa [1]). On the other hand the Young s moduli, E, in the range 300-600 GPa, are lower than the cBN bulk values (800-900 GPa) [1]. Mirkarimi et al. [73] explain this discrepancy by substrate effects which decrease with increasing film thickness. 

Microwear tests performed using atomic force microscopy (AFM) were reported by Miyake et al. [74] and by Schiitze [55]. The result was that the wear caused by a diamond tip is much greater for hBN than for cBN. The microwear rates of sputter deposited cBN films were found to be nearly the same as that of hard diamond like carbon films [55]. 

Friction coefficients, p, of cBN films were measured under different conditions (counterpart, humidity, number of cycles, sliding speeds) at normal loads up to ION. Data available from the literature are summarized in Table 3. In all cases considered hBN films had clearly higher friction coefficients than cBN. 

Firsts attempts to apply cBN coatings for wear protection on drills were reported already in 1990 by Murakawa and Watanabe [77]. Owing to the still unsolved problem of depositing films of several micrometers thickness, no essential progress in tool applications of cBN films has been made so far. 

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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. 

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

H. Nakazawa, A. Sudoh, M. Suemitsu, K. Yasui, T. ltoh,T. Endoh, Y. Narita, M. Mashita, Mechanical and tribological properties of boron, nitrogen-coincorporated diamond-like carbon films prepared by reactive radio-frequency magnetron sputtering., Diamond and Related Materials, vol. 19, pp. 503-506, 2010. 

From the above study, it may be concluded that CNT-PE composites show a good enhancement of mechanical and tribological properties with an increase of CNT loading. The measure of reinforcement... 

CNT has already been exploited in NEMS as the basis for a rotary element for a magnetically actnated nano-plate [96] and additional NEMS devices relying on both the novel mechanical and electrical properties of CNTs wiU continne to be developed in the years to come. Composite materials containing CNTs, especially inorganic material/CNT blends, have been demonstrated to have enhanced mechanical and tribological properties, unattainable with current metallurgical techniques [97]. These electroless and electrodeposited composites wiU provide a new class of materials available for MEMS and NEMS devices. 

Nishitani, Y. Ohashi, K. Sekiguchi, I. Ishii, C. Kitano, T. (2010). Influence of Additon of Styrene-Ethylene/Butylene-Styrene Copolymer on Rheological, Mechanical and Tribological Properties of Polyamide Nanocomposites. Polymer Composites, Vol.31, No.l, pp. 68-76 ISSN 0272-8397... 

Wan Wang, L. L., Zhang, L. Q., Tian, M. Mechanical and tribological properties of acrylonitrile-butadiene mbber filled with graphite and carbon black. Materials and Design 39 (2012) 450-457. 

Carbon-based polymer nano composites represent an interesting type of advanced materials with structural characteristics that allow them to be applied in a variety of fields. Functionalization of carbon nanomaterials provides homogeneous dispersion and strong interfacial interaction when they are incorporated into polymer matrices. These features confer superior properties to the polymer nanocomposites. This chapter focuses on nanodiamonds, carbon nanotubes and graphene due to their importance as reinforcement fillers in polymer nanocomposites. The most common methods of synthesis and functionalization of these carbon nanomaterials are explained and different techniques of nanocomposite preparation are briefly described. The performance achieved in polymers by the introduction of carbon nanofillers in the mechanical and tribological properties is highlighted, and the hardness and scratching behavior of the nanocomposites are also discussed. 

PA-6/UHMWPE/ HDPE-g-MA Brabender mixer/mechanical and tribological properties/FTIR Wang et al. 2007b... 

Lehmaim (2011) prepared compatibilized blends of PPS and PTFE (component ratios 0-100 to 100-0) using melt-processable PTFE treated by radiation to introduce -COF and -COOH functional groups by chain scission. It was proposed that functional groups on PTFE may react with thiol end-groups on PPS. Blend characterization techniques included mechanical and tribological properties. 

Well dispersed potassium titanate whiskers can serve as partially heterogeneous nucleating agents in PEEK resin to promote its crystallization, which is beneficial in increasing the mechanical and tribological properties of PEEK. ... 

W. Brostow, W. Chonkaew, K.P. Menard, T.W. Scharf, Modification of an epoxy resin with a fluoroepoxy oligomer for improved mechanical and tribological properties. Mater. Sci. Eng. A 507 (1) (2009) 241-251. 

Polymer Suiface Modifications The growing need of polymeric materials with specific properties for sophisticated applications has led to the development of new polymer surfaces, which can be created by traditional polymerization processes or by the modification of existing surfaces. Surface modification of polymers is used to improve their chemical, physical, mechanical, and tribological properties. Many techniques have been applied to produce the desired surface properties, ranging from thermal treatments, chemical and electrochemical modifications, metallization, and electrical treatments, to plasma treatments and particle beam irradiation techniques. The literature shows that SIMS is a method of choice to characterize the results of such treatments. Hereafter we introduce some examples taken from published studies. 

S. Kim, N. Saka, J.-H. Chun, Pad scratching in chemical-mechanical polishing the effects of mechanical and tribological properties, ECS J. Solid Sate Sci. Technol. 3 (5) (2014) 169-178. 

Palabiyik M and Bahadur S (2000) Mechanical and tribological properties of polyamide 6 and high density polyethylene polyblends with and without compatibilizer, Wear 246 149-158. 

Youxi Lin, Chenghui Gao, Ning Li. Influence of CaCOj whisker content on mechanical and tribological properties of polyCether ether ketone) composites. Journal of Material Science Technology, 22(5) 584-588, 2006. 

B. Wetzel, F. Haupert, K. Friedrich, M. Q. Zhang, M. Z. Rong (2001) Mechanical and tribological properties of microparticulate and nanoparticulate reinforced polymer composites, Pmc. 13 ICCM, Beijing, 1021. 

The following section deals with the exact description of the preparation of nanosilica-reinforced epoxies by the sol-gel technique, and of the relation of their structure to various rheological, mechanical, and tribological properties. 

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