Effect of Various Dispersants on the Gel-Casting of Silicon Nitride

A high solid loading of dispersed silicon nitride slurry was prepared with various dispersants, which allowed a stable silicon nitride suspension with sintering additives (cordierite) in alkaline regions to a solid content of 45 vol%. Gum arabic, PMAA-NH4, TMAH, PAA-NH4 and their composites were selected as dispersants. The results suggested that the composite dispersant which was obtained using PAA-NH4 and TMAH with the ratio in 4:1 was more effective in aqueous silicon nitride powder suspensions system than simplex dispersant. The green bodies derived exhibited a mechanical strength as high as 8.7MPa and SEM photos revealed that the green body also had a high homogeneity.