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研究了热压制备的多壁碳纳米管-氧化铝复合材料的力学、电学性能及与显微结构的关系.通过添加4%(质量分数)的MWNTs(多壁碳纳米管),所得材料的断裂韧性KIC达到5.55MPa·m1/2,是相同条件下所得纯氧化铝断裂韧性的1.8倍.通过SEM观察发现,其增韧机制主要是碳纳米管对氧化铝晶界的钉扎机制,碳纳米管的拔出机制也有一定的作用.添加2%(质量分数)MWNTs,并采用不同的分散混合方式,在相同烧结成型条件下所得复合材料的KIC为3.97MPa·m1/2,和纯氧化铝相比有所提高;而其电阻率达到8.4×10?3?·m,和纯氧化铝相比,降低了14个数量级.研究发现,碳纳米管在复合材料中的增韧和提高导电性能方面的差异和复合材料的显微结构有很大的关系,而显微结构的差异又和制备工艺之间有直接的联系.
The mechanical and electrical properties of multi-walled carbon nanotubes (MWNTs) -sized alumina composites prepared by hot pressing were studied.The relationship between the microstructures and the mechanical properties of MWNTs (multi-walled carbon nanotubes) The fracture toughness KIC reaches 5.55MPa · m1 / 2, which is 1.8 times of the fracture toughness of the pure alumina obtained under the same conditions.It is found by SEM observation that the toughening mechanism is mainly the pinning mechanism of carbon nanotubes on the grain boundaries of alumina, carbon The extraction mechanism of nanotubes also has a certain effect.With the addition of 2% (mass fraction) MWNTs, and using different dispersion and mixing methods, the KIC of the composite obtained under the same sintering conditions is 3.97MPa · m1 / 2, and pure oxidation Compared with pure alumina, the resistivity of the aluminum oxide is reduced by 14 orders of magnitude compared with that of pure aluminum, and the results show that the toughening of carbon nanotubes in the composite and the improvement of the conductivity The differences in performance are strongly related to the microstructure of the composites, and the differences in microstructures are directly related to the manufacturing process.