Effects of dispersion surfactants on the properties of ceramic–carbon nanotube (CNT) nanocomposites

Gum Arabic (GA), Sodium Dodecyl Sulphate (SDS) and their mixture were used for the dispersion of multi-walled carbon nanotubes (CNTs) in an alumina matrix. A good dispersion at low loadings (0.5–1 wt%) of CNTs in alumina was achieved by an ultrasonic bath treatment. Dispersions were evaluated by UV–vis spectroscopy and agglomerate size analysis. The mixture of GA and SDS produced good dispersion as compared to GA and SDS alone. Nanocomposite powders were sintered by Spark Plasma Sintering (SPS). Microstructural, electrical and mechanical characterizations of sintered discs were carried out to evaluate the effectiveness of the different dispersants. The mixture of GA and SDS produced homogeneous and agglomerate-free CNT-alumina nanocomposites with higher electrical conductivity and indentation fracture toughness as compared to nanocomposites prepared using GA and SDS alone.