FABRICATION OF BARIUM ALUMINOSILICATE-SILICON NITRIDE-CARBON NANOTUBE COMPOSITES BY PRESSURELESS SINTERING

摘要

Barium alurninosilicate (BAS)-silicon nitride composites reinforced with different amounts (1,3 and 5wt%) and different types (1-2 um and 5-15um in length, both 20nm in diameter) of multiwall carbon nanotubes (MWNTs) have been fabricated by pressureless sintering. The effect of CNTs on the microstructure, compositional investigations, as well as mechanical characterization of these composites was investigated. Near fully compacted composites with good properties have been obtained by pressureless sintering. Carbon nanotubes have been preserved in the inter-granular places and had good adherence to matrix grains after the high-temperature processes. Moreover, large content of CNTs may inhibit the densification and the α→β-Si3N4 transformation of the composites. BAS glass served as an effective liquid phase sintering aid to preserve the carbon nanotubes and promote the densification of the CNT reinforced composites.