Influence of network structure on abnormally high viscosity of mixed slurries of silicon carbide nanopowder and polycarbosilane

Abstract

Silicon carbide powder, polycarbosilane (PCS) and xylene mixed slurries were prepared for viscosity measurement and microstructure observation. Absolute slurry viscosity and shear rate dependence of viscosity were investigated at various SiC concentrations and particle sizes. Temperature dependence of viscosity was also investigated. As the primary particle size in powders decreases, viscosity increases relatively at a low SiC concentration. Microstructure observation on diluted slurries revealed the existence of secondary particles composed with primary nanoparticles and network formation by physically or chemically contacted secondary particles. Some of the microstructure changes with shearing was consistent with a strong shear thinning phenomenon of slurry viscosity.