Department of Chemical Engineering, Xiangtan University, Xiangtan, 411005, Hunan, PR China.
J Nanosci Nanotechnol. 2020 Mar 1;20(3):1709-1714. doi: 10.1166/jnn.2020.17344.
In this article, nano-NbC particles toughened Si₃N₄-based ceramics were prepared by injection moulding and their mechanical properties along with toughening mechanism were studied. An increase of nano-NbC content, gradually homogenizes microstructure of the Si₃N₄-based ceramics along with increase in its density. However, the fracture toughness and flexural strength first increases and then decreases. The Si₃N₄-based ceramics demonstrate good comprehensive properties at the 15 wt% nano-NbC content and sintering temperature of 1550 °C (where the density is 85.3%, the flexural strength is 845 MPa, and the fracture toughness is 9.3 MPa·m), Backscattered electron imaging shows that nano-NbC particles can be well dispersed in the Si₃N₄ ceramic matrix by injection moulding and ceramics are toughened by crack deflection and microcracking effects. It was also found that increasing sintering temperature makes the -Si₃N₄ grain distribution more uniform by reducing the porosity.
本文采用注射成型工艺制备了纳米碳化铌颗粒增韧氮化硅基陶瓷，研究了其力学性能及增韧机理。随着纳米碳化铌含量的增加，氮化硅基陶瓷的微观结构逐渐均匀化，密度也随之增加。然而，断裂韧性和弯曲强度先增加后减小。在 15wt%纳米碳化铌含量和 1550°C烧结温度下（密度为 85.3%，弯曲强度为 845MPa，断裂韧性为 9.3MPa·m），氮化硅基陶瓷表现出良好的综合性能。背散射电子成像表明，纳米碳化铌颗粒通过注射成型可以很好地分散在氮化硅陶瓷基体中，陶瓷通过裂纹偏转和微裂纹效应得到增韧。研究还发现，通过降低孔隙率，提高烧结温度可以使-Si₃N₄晶粒分布更加均匀。
