Fabrication of textured Si₃N₄ ceramics with β-Si₃N₄ powders as raw material by gel-casting under strong magnetic field

The textured Si₃N₄ ceramics with β-Si ₃N₄ powders as raw material were fabricated by gel-casting under a strong magnetic field of 6 T and subsequent pressureless sintering. The results show that the a or b-axis of β-Si₃N₄ crystal is oriented parallel to the direction of magnetic field. The degree of texture in the green body reaches 0.72. With the increase of sintering temperature, the degree of texture in the sample increases from 0.74 at 1700 °C to 0.81 at 1800 °C. The bending strength of the Si₃N₄ ceramic depends on the orientation of grains.