The Effect of Fullerene Soot Nanoparticles on the Microstructure and Properties of Copper-Based Composites

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.

Thermal Conductivity of Composite Materials Copper-Fullerene Soot

“…For the samples obtained by mechanical milling, the experimental values are lower than the calculated ones, and with an increase in the FS concentration, the difference increases. As we noted earlier [10], the structure of the samples differs significantly depending on the material preparation method. Materials obtained by MLM have a homogeneous The experimental values for the samples obtained by molecular level mixing are close to the calculated ones.…”

“…For the samples obtained by mechanical milling, the experimental values are lower than the calculated ones, and with an increase in the FS concentration, the difference increases. As we noted earlier [10], the structure of the samples differs significantly depending on the material preparation method. Materials obtained by MLM have a homogeneous and fine-grained structure (Figure 3a,c), while in the composites prepared by mechanical milling, a network consisting of recrystallized copper grains is observed (Figure 3b,d); this phenomenon was discussed in [10].…”

“…The Cu particles were dendrite crystals with an average size of 40 µm. Cu-FS powder of assigned FS concentration was produced in a planetary mill Fritsch Pulverisette 7 premium line ball mill (FRITSCH, Markt Einersheim, Germany), with steel balls in argon at 200 rpm and 600 rpm; a detailed description of the process is given in [10].…”

“…The samples were compacted by cold pressing at a pressure of 400 MPa, followed by hot pressing at 750 • C and a pressure of 200 MPa [10,11]. The density of the composites was determined by Archimedes' principle.…”

“…In previous works [10,11], we showed the possibility of obtaining composite materials of the Cu-fullerene soot (FS) system with physical and mechanical characteristics at the level of copper-CNTs materials. Fullerene soot is a mixture of fullerenes with amorphous carbon and has a lower cost compared to pure fullerenes and CNTs.…”