Effects of Surface Modification on Solid Loading of Silicon Nitride Slurries

Surface modification of Si_3N_4 particles by acid leaching and its effects on the colloidalbehavior and the flow properties of Si_3N_4 aqueous slurries were investigated. The experimentalresults indicate that the isoelectric point of St_3N_4 particles shifts to basic region after modificationdue to the decreasing of the oxidizing degree on the surface of Si_3N_4 modified. Because theZeta potential of Si_3N_4 particles increases efficiently, the flow properties of St_3N_4 modified slurrysignificantly improve and the maximum solid loading increases from 50 to 55vol.%. Moreover, the53vol.% Si_3N_4 slurry suitable for casting was prepared.