The dispersion property of Si3N4 was studied when ammonium polyacrylate was used as dispersant. And
the influences of acid leaching and thermal oxidation on aqueous dispersibility were investigated. The results indicated
that the best dispersing effect could be obtained when the ratio of ammonium polyacrylate was 0.2 wt% and pH=9. After
acid leaching, both the width and the value of particle diameter became smaller. The contamination of metal can be
eliminated efficiently by acid leaching. After themal oxidation, the viscosity of Si3N4 suspension dropped significantly.