改性SiC短切纤维体积分数对SiC_(sf)/LAS复合材料介电性能的影响

Effect of Volume Fraction of Improved Short SiC Fibres on the Dielectric Properties of SiC_(sf)/LAS Composite

以改性SiC短切纤维为添加剂,用热压法制备了SiCsf/LAS复合材料,考察了纤维的显微结构以及纤维和复合材料在8.2～12.4GHz频率范围内的微波介电性能。结果表明,当SiC纤维的体积分数为2.92时,纤维混合体介电常数实部、虚部最大,分别为38～25、40～20。高复介电常数的SiC纤维使SiCsf/LAS复合材料比LAS具有更高的介电常数,材料中无富碳界面层的形成。当SiC纤维的体积分数为3时,复合材料介电常数实部、虚部以及损耗角正切值最大,其均值分别为58、25和0.45。

The SiCsf/LAS composites were prepared by hot-press sintering method in the presence of improved short SiC fibres as addition agents. The microstructure of the fibre and the microwave dielectric properties of the fibre and the composite in the frequency range of 8.2 - 12. 4 GHz were investigated. The results show that the permittivity of the fibre mixture gets the maximum when the volume fraction of the fibre is 2. 92%, where the real part and imaginary part of permittivity are 38-25 and 40-20, respectively. All the SiC sf/LAS composites have higher values of permittivity than LAS, and there is no carbon interface between the fibre and the matrix. When the volume fraction of the fibre is 3% ,the SiCsf/LAS composite has maximum permittivity,of which the average values of real part, imaginary part and loss tangent are 58,25 and 0. 45 ,respectively.