Effect of Sintering Pressure on Mechanical Properties of BN-Si₃N₄ Ceramic Composites Prepared by Spark Plasma Sintering

Abstract:

BN-Si₃N₄ composite ceramic wave-transparent materials with excellent mechanical properties were prepared by spark plasma sintering (SPS) using h-BN and α-Si₃N₄ powders as raw materials, Al₂O₃ and Y₂O₃ as sintering aids. The influence of sintering pressure on density and mechanical properties of BN-Si₃N₄ composite ceramics were studied. The phases were observed by X-ray diffraction (XRD), and the microstructures were identified by scanning electron microscopy (SEM). The results showed that with the sintering pressure increases, the relative density, bending strength and fracture toughness of the composite ceramics were significantly increased, and the porosity decreased rapidly. The effects of pressure on the properties of the composite ceramics was not significant at >40MPa, so 40MPa is optimal for the composite ceramics to gain good overall performance, i.e. the relative density was 89.1%, the porosity was 2.3%, the bending strength reached 215.4 MPa, and the fracture toughness was 3.1/MPa·m^1/2.

• Periodical: Key Engineering Materials (Volume 697)
• Pages: 188-192
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.697.188
• Online since: July 2016
• Authors: Jia Xin An, Wen Dong Xue*, Feng Rui Zhai, Ruo Meng Xu, Jia Lin Sun
• Keywords: Boron Nitride, Composite Ceramics, Mechanical Properties, Silicon Nitride, Spark Plasma Sintering (SPS)

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