Abstract
Copper-based composite materials strengthened with nanosized fullerene soot particles were produced by mechanical milling and hot pressing technology with a content of carbon up to 5 wt. %. The microstructure of the composite powders and the compacts prepared using them were examined by light microscopy, SEM, EDS, XRD, and XPS; hardness, heat conductivity, and tribological characteristics were measured. The interesting feature of the observed microstructure was a “marble” pattern formed by a white boundary net. The study shows homogeneous distribution of carbon inside the copper grains and its lower concentration in the grain boundaries. The effect was caused by a reaction of carbon with oxygen adsorbed by the copper particles surface. The maximal hardness of the material is 160 HB for the sample with 0.5 wt. % of fullerene soot; this material has the minimal friction coefficient (0.12) and wear in a dry friction condition. Heat conductivity of the material (Cu-0.5 wt. % C) is 288 W/m*K.
Highlights
IntroductionCopper-based composites reinforced with carbon nanoparticles attract interest due to a combination of mechanical and electrical properties [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]; besides, these composites mostly have low friction coefficient and wear [14,15,16,17,18,19], which is necessary for sliding contact application
It is widely known that the strength of a material depends on its grain size, and the effect is described by the Hall–Petch equation σ = σ0 + Kd-1/2
In the process of ball milling, carbon does not diffuse to copper lattice, but distributes between its layers
Summary
Copper-based composites reinforced with carbon nanoparticles attract interest due to a combination of mechanical and electrical properties [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23]; besides, these composites mostly have low friction coefficient and wear [14,15,16,17,18,19], which is necessary for sliding contact application. In the recent work in [28], the influence of fullerene additions on structure and phase composition of Cu-C composite powders was discussed, but properties of compacted materials were not studied. Another type of carbon material, which may be considered a reinforcement to Cu-based composites, is fullerene soot (FS). With the exception of these very fine particles, the soot contains fullerene structures and occasionally observed large crystals of carbon black [29] These characteristics—very small size, round shape, and narrow size distribution—might be prospective factors in order to use the soot as a phase for dispersion strengthening. The effects of FS on hardness and thermal conductivity of the Cu-based composites were evaluated
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