ALUMINUM NITRIDE MULTI-WALLED NANOTUBE (MWNTs) NANOCOMPOSITE BY DIRECT IN-SITU GROWTH OF CNTs ON ALUMINUM NITRIDE PARTICLES

摘要

Aluminum Nitride (ALN) - Carbon Nanotube (CNT) composites were prepared to increase the fracture toughness, flexural strength and thermal conductivity of AlN based ceramics by direct in-situ growth of CNTs on the mixtures using Chemical Vapor Deposition (CVD) technique. The AlN- 3 wt% Yttria (Y_2O_3) base mixtures with in-situ grown CNTs were then spark plasma sintered at 1950℃ in vacuum under a pressure of 60MPa. The Vickers Hardness decreased with the addition of CNTs in the matrix whereas the indentation fracture toughness increased with addition of CNTs. The flexural strength increased for mixtures with 7 wt% CNTs by comparison to base AlN-3 wt% Y_2O_3 samples. Detailed electron microscopy analysis of the Aluminum Nitride-CNT powders shows uniform distribution of CNTs in the matrix, without the formation of agglomerates frequently seen with traditional ex-situ mixing of CNTs in ceramic compositions. The samples sintered by spark plasma sintering showed a finer grain size microstructure in the presence of CNTs compared to base samples. Mechanical and thermal properties show an enhancement with the addition of CNTs in the matrix. Raman Spectroscopy and high resolution transmission electron microscopy confirms CNT retention in the sintered nanocomposite.