Enhancing dispersion of ultra-fine WC powders in aqueous media

The dispersion of WC particles is critical to the microstructures and properties of WC-based alloys. The ultra-fine WC powders were uniformly dispersed in aqueous media via sodium dodecyl sulfate (SDS) with physical means. The influence of dispersion conditions such as concentration of dispersant, dispersion time and solid-liquid ratio on the powders dispersion was investigated by sedimentation test in present work. The particle size and distribution of WC powders, phase analysis and microstructure were characterized by the laser particle size analyzer, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Transmission electron microscope (TEM) and Zeta potential respectively. The results show that SDS was adsorbed and scattered on the WC powders, which could enhance the stability and dispersibility of suspension by the electrostatic effect. The diameter of dispersed WC powders ranged from 0.2 to 0.8 mu m. The corresponding dispersive mechanisms of SDS were electrostatic repulsion and static hindrance, which kept the dispersibility and stability of the suspension. Furthermore, the optical dispersing time, solid-liquid ratio and the concentration of SDS for the dispersed WC powders in this work is 3 h, 1:50 and 1.44 g/L, respectively.