Study On The Surface Character And The Dispersion Stability Mechanics In The Water Of Modified SiC Fine Powder

Coat and modify silicon carbide(SiC) fine powders with coupling agent, salicylic acid, acrylamide, and a new agentia which mix the salicylic acid and acrylamide, respectively. Through the compare among the several kinds of modified SiC powders' surface property , the dispersity and the rheological behavior, the research finded the SiC fine powder modified with the salicylic acid and acrylamide together have the highest Zeta electric potential 58mV when the pH=11.5. The highest solid content of the slurry of the SiC powder reach 58.6%. Research the coating system and modify technology how to effect the disperse stability and rheological performance when the SiC powder disperse in the water.The dispersed and stabilized SiC powder coated with WD-60/salicylic acid under aqueous condition is obtained by the mechanism of electrostatic stabilization. For SiC powder coated with WD-20/acrylamide, because of the -COO" in the polymer, the dispersed and stabilized slurry is obtained by the mechanism of steric stabilization, and the viscosity of which is lower. SiC powder coated with WD-60/salicylic acid and WD-20/acrylamide can be highly dispersed and stabilized by the mulriple mechanism of electrostatic stabilization and steric stabilization.Then the highly dispersed and stabilized slurry is obtained , of which the solid loading is higher and the viscosity is lower.In the surface structure of coated SiC powder, amino and carboxy can change into ionic and modify the Zeta electric potential of SiC fine powder;For the polyacry lamide will have varied structure on the surface of SiC powder when the length of the semger of the polyacry lamide chang, the polyelectrolyte such as the polyacry lamide can formate the electrostatic and space steric hindrance stabilize effect.Coated SiC powder can achieve good rheological performance in low Zeta electric potential when the electrostatic stabilize effect and space steric hindrance stabilize effect act at the same time. The hydrophilia and oleophylic group in the variant proportion on the SiC powder will effect the rheological performance of the SiC slurry, and the SiC powder will have better rheological performance in the water if proper quantities oleophylic groups are coated on the surface of SiC powder.