Preheat treatment seed synthesis and tape-casting strategy for cost-effective fabrication of textured silicon nitride ceramics with high strength and toughness

This study develops a preheat treatment synthesis method that readily produces easily dispersible β-Si 3 N 4 seeds with uniform and moderate dimensions. The as-prepared β-Si 3 N 4 seeds enabled successful fabrication of textured Si 3 N 4 ceramics through tape casting. The plane parallel to the casting direction exhibited well-defined in-plane orientation of predominantly rod-like β-Si 3 N 4 grains, while the transverse cross-section showed axial orientation dominated by hexagonal grains. XRD quantification indicated a significantly higher I 210 /I 002 intensity ratio of β-Si 3 N 4 for the parallel direction compared to the transverse direction. Mechanical properties testing revealed notable anisotropy, with the parallel direction displaying a balance of strength and toughness (1105 MPa and 12.69 MPa m 1/2 ). This significant improvement in mechanical properties is attributed to the aligned orientation of the seeds and the high-aspect-ratio grains developed from these seeds. The work offers a cost-effective route for manufacturing high-performance ceramics, demonstrating significant potential of Si 3 N 4 in the application as a backplane material for smart wearable devices.