A novel Si3N4/BAS/BN composite synthesized by spark plasma sintering

Based on good thermomechanical and electromagnetic properties of silicon nitride (Si3N4), barium aluminosil-icate (BaO-BaTiO3-SiO2 or BAS), and boron nitride (BN), a novel combination of Si3N4/BAS/BN composites was fabricated by spark plasma sintering (SPS) after traditional powder mixing process. The effect of different amounts of BN (3-9 wt%) on the mechanical properties of composite was studied. The phases were observed by X-ray diffraction, and the microstructures were identified by scanning electron microscopy (SEM). The optimal sample is the one containing 3 wt% of BN and is sintered under a final pressure of 50 MPa. This sample has a hardness of 9.03 GPa, a flexural strength of 418.75 MPa, an elastic modulus of 934.46 MPa, and a loss tangent of less than 0.002 in 38% of the X-band frequencies. The optimal sample thickness was determined via the Nicolson-Ross-Weir (NRW) technique considering the mechanical strength limits.

Automated summary

By using good thermomechanical and electromagnetic properties of silicon nitride (Si3N4), barium aluminosilicate (BaO-BaTiO3-SiO2 or BAS), and boron nitride (BN), a novel combination of Si3N4/BAS/BN composite was successfully fabricated via spark plasma sintering (SPS) after traditional powder mixing process. The effect of different amounts of BN (3-9 wt%) on the mechanical properties of the composite was investigated. The optimal sample, containing 3 wt% of BN and sintered under a final pressure of 50 MPa, exhibited excellent mechanical properties and low loss tangent in the X-band frequencies range. The optimal sample thickness was determined considering the mechanical strength limits using the Nicolson-Ross-Weir (NRW) technique.