Influence of nanopowder characteristics on dispersion property of slurries

To investigate the effect of nanopowder characteristics on the slurry properties, the comparative studies on three types of SDC nanopowder synthesized by different methods, i.e., hydrothermal (commercial, SDC I), sol–gel (commercial, SDC II) and citric-nitrate combustion (lab-made, SDC III), were carried out. The powder properties were investigated using X-ray diffraction, BET surface area and laser particle size analysis. The slurry stability was confirmed by zeta potential and sedimentation experiments. The samples were similar in the powder sizes, shapes and agglomeration degrees. However, when these samples were dispersed into slurry, the deagglomeration behaviours of particles and dispersion stabilities were significantly different. The powders consist of agglomerates with the average sizes of about 5 μm; these agglomerates were primary composed of particles with the average size of 20–30 nm. After dispersion, the agglomerates sizes of SDC I, II, and III were reduced to 454.7, 120.5, and 54.8 nm, respectively. The slurry of lab-made SDC nanopowders was the most stable, which resulted from soft agglomeration originated from the nature of synthesis process.