Effects of seeding and amounts of Y2O3:Al2O3 additives on grain growth in Si3N4 ceramics

The effect of changing the Y2O3:Al2O3 additive ratio over grain growth of Si3N4 materials with and without β-seeds addition is studied. Increasing the amount of Al2O3 from 2 to 4 wt.% strongly affects grain growth in non-seeded materials whereas it hardly does in seeded ones. Results suggest that β-seeds addition changes the rate limiting step for the Si3N4 grain growth from diffusion to interfacial reaction.