反应烧结工艺制备碳纳米管/氮化硅陶瓷基复合材料

CARBON NANOTUBES/SILICON NITRIDE CERAMIC MATRIX COMPOSITES FABRICATED BY REACTION-BONDED PROCESS

用反应烧结工艺在1550℃制备了碳纳米管（carbon nanotubes，CNTs）／Si3N4陶瓷基复合材料，借助x射线衍射、扫描电镜、透射电镜、标量分析等分析手段，研究了反应烧结CNTs／Si3N4复合材料的物相组成、化学相容性、力学性能及电磁性能。结果表明：反应烧结CNTs／Si3N4复合材料主要由α-Si3N4和β-Si3N4组成，还含有少量的游离硅。CNTs和Si3N4基体之间具有良好的化学相容性。含有1．0％（质量分数）CNTs的反应烧结CNTs／Si3N4复合材料的抗弯强度为280MPa，Vickers硬度为8．2GPa，断裂韧性为2．3MPa·m^1/2，在8～12GHz（X带）具有明显的微波衰减特性，在10GHz处的最大衰减值达7dB，可用作微波吸收材料。

Carbon nanotubes （CNTs）/Si3N4 ceramic matrix composites were prepared at 1 550℃ by reaction-bonded process. The phase compositions, chemical compatibility, mechanical properties, and electromagnetic properties of the composites were investigated by X-ray diffraction, scanning electron microscope, transmission electron microscope, and a scalar measurement system. The results show that the composites consist mainly of α- Si3 N4 and β- Si3 N4 with a trace of unreacted silicon. There is good chemical compatibility between the CNTs and the Si3N4 matrix. The composite with 1.0%（in mass） CNTs has a bending strength of 280 MPa, Vickers hardness of 8.2 GPa, and fracture toughness of 2.3 MPa ·m^1/2. The composite displays microwave attenuation at 8-12 GHz （generally called the X-band）. The peak value of the transmission attenuation reaches 7 dB at 10 GHz, indicating that the composites have a potential application in electromagnetic adsorption.