Effect of pretreatment on rheological properties of silicon carbide aqueous suspension

The effect of surface treatments, including leaching with acid solution, base solution and deionized water, on flow properties of SiC aqueous slurry has been studied. The SiC powder was well dispersed irrespective of the surface treatment. However, the viscosity was affected by the surface treatment. Base leaching exhibits a distinctly lower viscosity. The reason for the leach effect was discussed. Calcination of SiC powders at 550 °C is observed to effectively reduce the viscosity of the SiC slurry. But further increase of the calcination temperature will be deleterious to the rheologic properties. The hydration of amorphous SiO2 on the SiC surface is used to clarify the phenomenon.