Abstract: Mullite-zirconia composites were prepared by reaction-sintering of zircon and α-Al₂O₃ mixed powders. Densification process as well as formation
mechanism of mullite was studied and discussed, and special attention was paid to the effect of mullite seeding on the reaction-sintering mechanisms. It is
shown that the viscous flow of the non-crystalline may be a dominant densification mechanism prior to the formation of mullite. Mullite seeding has an obvious influence
on the forming way of mullite, and a higher relative density of 97% can be obtained when a small amount of mullite seeds (3wt%) are added.

Key words: reaction-sintering mechanism, mullite, zirconia, composite