ИСТИНА

Low density and dust generation of carbon nanotubes (CNTs) prevent their broad application. In different types of electrochemical devices these problems are usually overcome by mixing of CNTs with the conductive soot. CNTs are also promising support for metal catalysts1 but they need to be in compact and safe state to be applied in a large scale. Spark plasma sintering (SPS) has been widely used in ceramics fabrication. It allows direct application of very high heating and cooling rates. This work focuses on the new application of SPS technology: production of compacted and dense material contained carbon nanotubes and metal nanoparticles. Such composite materials are promising to be applied in energy storage devices, catalytic processes and magnetic data storage devices. In the present study we obtained the series of Me/CNTs composites where Me is Co, Fe, Ni and Cu. Image of the produced Co/CNT tablets is shown in Fig.1a. Different sintering temperatures (TS) and metal concentrations were used and the obtained materials were studied by TEM, SEM, XPS, XRD and Raman spectroscopy. It was found that TS, material density and metal content strongly affect the electro conductivity and phase composition of the samples. TEM experiments showed that the increase of TS resulted in the growth of metal particles and in the increase of their coverage by the carbon shell (Fig.1b, c). XRD results proved the reduction of Co oxides and the formation of fcc-Co0 during sintering at 1073 K. Specific conductance (σ) of the obtained Co-based materials varied in the range of 500-6000 S/m and the addition of 10 wt.% of Co into CNTs increased σ from 2700 S/m for the initial CNT tablet to 3700 S/m for Co/CNT one (TS = 1073 K). The transformation of CNT structure during SPS was also studied.