Synthesis and thermal stability of multiwall carbon nanotubes reinforced aluminum metal matrix composites

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ÎÄÕÂÒ³Â룺240 - 244

Key words£ºaluminum matrix composite£» multiwall carbon nanotubes(MWNTs)£» purification

Abstract: Multiwall carbon nanotubes£¨MWNTs£© reinforced aluminum composites were synthesized by hot press sintering. The thermal stability of MWNTs in the composite was investigated by transmission electron microscopy£¨TEM£©. The results show that the impurities drop from 2% to 0.11% after the MWNTs are soaked with 95%H₂SO₄ and 66%HNO₄ acids in an ultrasonator and washed with distilled water. In hot pressed composites, MWNTs distribute between aluminum powders and do not react with aluminum. When the composite was held at 800¤@¡æ for 1¤@h, MWNTs react with aluminum and form Al₄C₃ phase, which are small polygons and distribute in the aluminum grains. Although Al₄C₃ phase still forms when the composite was held at 1¤@000¤@¡æ for 1¤@h, its morphology changes to a continuous band and distributes along the origin aluminum powder boundaries. So MWNTs are unstable in aluminum matrix composites that are kept above the liquidus temperature of aluminum.