Effect of β-Si 3N 4 seed particles on the property of sintered reaction-bonded silicon nitride

• Published in: Ceramics international Vol. 29; no. 8; pp. 897 - 905
• Main Authors: Lee, Joo-Sin, Mun, Ji-Hun, Han, Byung-Dong, Kim, Hai-Doo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 2003
• Subjects: Elongated grain; Mechanical properties; Powders-gas phase reaction; Sintered reaction-bonded silicon nitride; β-Si 3N 4 Seed; Sintered reaction-bonded silicon nitride; Powders-gas phase reaction; Mechanical properties; β-Si 3N 4 Seed; Elongated grain
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/S0272-8842(03)00034-8

The effect of seeding on the microstructural development and mechanical properties of sintered reaction-bonded silicon nitride was investigated by the use of β-Si 3N 4 particles. Seeding of an appropriate amount of the β-Si 3N 4 particles gave rise to the promotion of density and the resulting increase in fracture strength and hardness. The fracture toughness was also increased due to the development of elongated grains. On the other hand, addition of a large amount of seed particles showed lower strength and fracture toughness owing to the coalescence of large elongated grains. By seeding of 2 wt.% β-Si 3N 4 particles on Si powders of 7 μm, high fracture strength of 1100 MPa and fracture toughness of 7.2 MPa·m 1/2 were obtained in sintered reaction-bonded silicon nitride ceramics.