Influence of carbon nanotubes and carbon particles on tribological properties in aluminum based composites
Bartosz Hekner, Jerzy Myalski, Nathalie Valle, Agnieszka Botor-Probierz
Quarterly No. 1, 2014 pages 43-49
DOI:
keywords: carbon nanotubes, glassy carbon, friction coefficient, wear, wear mechanisms
abstract This paper presents the tribological characteristics of friction materials manufactured for a high loaded friction point. Composite powders containing 1% carbon nanotubes or 5% glassy carbon particles were produced by high energy milling in planetary mills. High energy during powder preparation led to reinforcement particle fragmentation up to sizes between 0.1÷2 µm. Furthermore, mechano-chemical bonding between the reinforcement and the Al particles used as the matrix was obtained during this process. As a result of the pressing and sintering processes, composite materials with homogeneous reinforcement (SiC) or heterogeneous reinforcement (SiC with addition of 1 wt.% multiwalled carbon nanotubes (CNT) or 5 wt.% glassy carbon particles) were manufactured. The properties of the obtained composite materials were measured during tribological tests at room temperature (25°C) and high temperature (450°C). The tribological research was conducted by the ball-on-disc method, at a distance of 250 m, with a load of 10 N and sliding speed of 0.1 m/s. The analyses of the friction coefficient and wear results revealed the desirable influence of the carbon components especially in increasing the average value and stabilization of the friction coefficient, particularly at room temperature. Moreover, the carbon additions led to a decrease in wear in comparison to the composite reinforced with SiC particles only. The changes in the wear level and friction coefficient value are a result of the differences in the predominant wear mechanism observed between the friction surfaces of the composite materials at room and high temperatures.