Effect of Tungsten Carbide on Densification and Mechanical Properties of Silicon Nitride Ceramics by Spark Plasma Sintering

Abstract:

The high-performance silicon nitride ceramics were prepared by spark plasma sintering (SPS) with Al₂O₃–Y₂O₃ as a sintering aid.A novel approch was adopted to fabricate the silicon nitride by introducting WC via mechanical ball milling.The effects of tungsten carbide on densification and mechanical properties of silicon nitride ceramics were inverstigated.The results show that the introduction of tungsten carbide effectively reduces the activation energy of β phase precipitation and growth, which promotes the phase transformation of silicon nitride ceramic , and the densification of sintered samples. Tungsten carbide can dissolve into the matrix lattice partly.With the increase of the amount of tungsten carbide, the flexural strength of sintered samples increased from 735.2MPa to 1091.2MPa, which increased by 48.4%.