Preparation of B4C-Al and B4C-Al-CNT Composite Materials by Means of Infiltration
G. R. KARAGEDOV
Institute of Solid State Chemistry and Mechanochemistry, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: carbon nanotubes, boron carbide, aluminium, composite
Abstract
A compacted matrix of boron carbide has been infiltrated by molten aluminum. It is shown that under the external mechanical action on aluminium, presumably simplifying the destruction of oxide film on molten metal, the temperature of boron carbide wetting decreases from 1100-1200 to 830-850 °C, and this prevents the formation of unfavourable aluminium carbide that could worsen the mechanical properties of composite material. Dense ceramic composites with the density within the range of 2.45-2.58 g/cm3, Vickers hardness up to 21 GPa and fracture toughness at a level of 3.5-4.5 MPa · m1/2 have been obtained. It has also been determined that, although carbon nanotubes react with molten aluminium, a considerable amount of them is preserved during infiltration at temperatures below 950°С, which allows one to synthesise the соmposite material reinforced with nanotubes.
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