Preparation and properties of carbon fiber/Si3N4composites

作者：Wang, He-Yun; Liu, Qian; Zhou, Yao; Zhou, Zhen-Zhen; Liu, Guang-Hui

来源：Journal of Inorganic Materials, 2014, 29(9): 1003-1008.

DOI：10.15541/jim20140165

• Ball milling process
• Dispersion medium
• High-temperature sintering
• Hot-press sintering
• Short carbon fibers
• Silicon carbides (SiC)
• Sintering additives
• Vertical direction

To investigate the effects of carbon fiber (Cf) adding content on the properties of Si3N4, Cf/Si3N4composites with 0, 2 wt% and 5 wt% of short carbon fibers were prepared by hot-press sintering method, using Y2O3as sintering additives.With long-time ball milling process, carbon fibers were well dispersed in mixed powders using ethanol as dispersion medium. Carbon fibers distribute uniformly in the composites and Si3N4grains grow to a certain degree in the vertical direction to the pressure of hot-press. The interfacial by-product silicon carbide (SiC) phase forms due to the reaction between added Cfand Si3N4particles or SiO2layer on surface of Si3N4particles during high temperature sintering. The sample with 2 wt% Cfaddition achieves a higher value of thermal conductivity (45.8 W/(m·K)), while the thermal conductivity of Si3N4without Cfis only 37.1 W/(m·K). Therefore, the addition of Cfcan improve the thermal conductivity of the composites. The fracture toughness of the composites has a slight increase with Cfadding. The measured hardness values for all samples are within a range of 16.6-16.8 GPa.

• 单位
  高性能陶瓷和超微结构国家重点实验室; 中国科学院大学