Effect of seed particles content on texture formation of Si₃N₄ ceramics by gel-casting in a strong magnetic field

Abstract

In this paper, the textured Si₃N₄ ceramics were prepared by adding seed particles during gel-casting in the magnetic field of 6 T, followed by pressureless sintering. The effect of pH on the stability and dispersibility of Si₃N₄ slurry and the effect of seed particles content on texture formation of Si₃N₄ ceramics were both studied. Those results showed that the slurry with good stability and dispersibility was obtained when pH was about 11.6. The a or b-axis of Si₃N₄ particles or crystals was aligned parallel to the direction of the magnetic field in the magnetic field of 6 T. The degree of texture of Si₃N₄ ceramics further increased during sintering. With the increasing of additional β-Si₃N₄ particles in the magnetic field of 6 T, the degree of texture increased from 0.19 without seed particles to 0.76 with 9% (mass fraction) seed particles. The increase of seed particles content promoted the texture formation of Si₃N₄ ceramics.

Keywords

Silicon nitride / Gel-casting / High magnetic field / Texture / Pressureless sintering