Dispersion and co-dispersion of ZrB2 and SiC nanopowders in ethanol

The dispersion and co-dispersion behavior of ZrB2 and SiC nanopowders in ethanol solution was studied by sedimentation test, particle size measurement and transmission electron microscope (TEM) analysis. The dispersion behavior of ZrB2 and SiC nanopowders in ethanol solution was strongly dependent on the pH values, types and amounts of dispersant. PEI was found to be effective for the dispersion of both ZrB2 and SiC nanopowders in ethanol solution. With the addition of PEI, the isoelectric points of ZrB2 and SiC nanopowders in ethanol solution were at pH 10 and pH 9.5, and shift to pH 13 and pH 12.3, respectively. The stability of ZrB2 suspension increased with the dispersant content increasing until reached 0.7 wt% and well-dispersed SiC slurry can be obtained with more than 2.5 wt% PEI. The suitable pH value for the dispersion of ZrB2 and SiC nanopowders should be lower than 12 and 10, respectively. The well co-dispersed ZrB2 and SiC nanocomposite powders can be achieved by using 1 wt% or more PEI below pH 10.