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研究了纳米SiC粉体和纳米SiC(N)复相粉体在 8．2~12．4 GHZ频率范围的介电特性及其与微波的作用机理,发现纳米SiC(N)复相粉体介电常数的实部(ε’)和虚部(ε”)在8．2~12．4 GHZ范围内随频率增大而减小,介电损耗(tgδ=ε”/ε’)较高,是较为理想的微波吸收材料。纳米SiC粉体的ε’、ε和tgδ明显小于纳米SiC(N)复相粉体的,对微波的吸收不理想。提出了纳米SiC(N)复相粉体对微波的吸收机理。纳米SiC(N)复相粉体中的SiC微晶固溶了大量的N原子,在纳米SiC(N)复相粉体中形成大量的带电缺陷,这些带电缺陷在电磁波交变电场作用下产生极化耗散电流,强烈的极化弛豫过程导致大的介电损耗。
The dielectric properties of nano-SiC powder and nano-SiC (N) composite powder in the frequency range of 8.2 ~ 12.4 GHZ and their interaction mechanism with microwaves were investigated. It was found that the nano SiC (N) The real part (ε ’) and the imaginary part (ε “) of the electric constant decrease with increasing frequency in the range of 8.2 ~ 12.4 GHZ, the dielectric loss (tgδ = ε” / ε’) is higher, Is the ideal microwave absorbing material. The ε ’, ε and tgδ of nano-sized SiC powders are obviously smaller than that of nano-SiC (N) composite powders, and the absorption of microwaves is not ideal. The microwave absorption mechanism of nano-SiC (N) composite powder was proposed. SiC microcrystal in nano-SiC (N) composite powder solid solution a large number of N atoms in the nano-SiC (N) complex powder to form a large number of charged defects, these charged defects generated in the electromagnetic wave alternating electric field Polarization Dissipation Current, a strong polarization relaxation process leads to large dielectric losses.