摘要
采用双反应室激光气相合成纳米粉体装置 ,以六甲基二硅胺烷 ((Me3Si) 2 NH) (Me:CH3)为原料合成了纳米 Si/ C/ N复相粉体 ,粒径为 2 0 nm～ 30 nm。研究了纳米 Si/ C/ N复相粉体在 8.2 GHz～ 18GHz的微波吸收特性 ,结果表明 :纳米 Si/ C/ N复相粉体介电常数的实部 (ε′)和虚部 (ε″)在 8.2 GHz～ 18GHz随频率增大而减小 ,介电损耗 (tgδ=ε″/ε′)较高 ,是较为理想的微波吸收材料 ;纳米 Si/ C/ N复相粉体在不同基体中的微波吸收特性出现很大差异。纳米 Si/ C/ N复相粉体中的 Si C微晶固溶了大量的 N原子 ,形成大量带电缺陷 ,极化弛豫是吸收微波的主要原因。根据纳米 Si/ C/ N复相粉体与石蜡复合体的实测介电参数 ,设计出多组在 8GHz～ 18GHz范围内微波反射系数 R≤ - 8d
The microwave absorbing property of nano Si/C/N composite powder has been studied in the frequency range of 8.2 GHz-18 GHz. The nano Si/C/N composite powder with its size in the range of 20 nm -30 nm was synthesized from hexamethyldisilazane (Me3)2NH) (Me:CH3) by a laser-induced gas-phase reaction. The dissipation factor of the nano Si/C/N composite powder was high at the microwave frequency. The microwave permittivity of the mixture of nano Si/C/N composite powder and paraffin wax or epoxy resin can be tailored by the content of this composite powder. The unusual Ε´, Ε´´ and dissipation factor tgδ(Ε´´/Ε´) of the nano Si/C/N composite powder suspended in different matrixes were attributed to the interface effect between the nano Si/C/N composite powder and matrix. The Ε´ and Ε´´ of the nano Si/C/N composite powder decreased with the increase of frequency in the range of 8.2 GHz to 18 GHz. The high Ε´´ and tgδ of nano Si/C/N composite powder were due to the dielectric relaxation. The microwave absorbing coating structure was designed on the basis of measured Ε and Ε´´ of the composite composed of nano Si/C/N powders and paraffin wax. Several three-layer microwave absorbing coatings with the reflection coefficient less than -8 dB in the frequency range of 8 GHz-18 GHz were designed with the depth of three millimeters.
出处
《复合材料学报》
EI
CAS
CSCD
北大核心
2002年第2期65-70,共6页
Acta Materiae Compositae Sinica
基金
航空基金资助项目
