Dimethylformamide: an effective dispersant for making ceramic–carbon nanotube composites

Carbon nanotube (CNT) and alumina dispersions were prepared separately in dimethylformamide (DMF) and ethanol by ultrasonication. The colloidal stability of the dispersions was monitored and a particle size analysis was performed to evaluate the size range of the agglomerates after different times. DMF was found to be a much more effective dispersant than ethanol for making stable, homogeneous CNT and composite dispersions. Alumina-CNT (4.65 vol%) nanocomposites were sintered in a spark plasma sintering (SPS) furnace. DMF dispersions produced homogeneously distributed and agglomerate-free CNT-alumina nanocomposites with higher electrical conductivity as compared to nanocomposites prepared using ethanol.