燃烧合成法制备N掺杂SiC粉体及其微波介电性能

Preparation and Microwave Dielectric Properties of N-Doped SiC Powders by Combustion Synthesis

采用燃烧合成法,以硅粉和炭黑为原料、固态氮化剂α-Si3N4为掺杂剂及聚四氟乙烯(polytetrafluoroethylene,PTFE)为化学活性剂,制备N掺杂的β-SiC粉体吸收剂。通过X射线衍射分析和扫描电子显微镜对燃烧产物进行了表征。结果表明:PTFE含量为10wt%时,燃烧产物中β-SiC的纯度较高,具有较好的颗粒形貌。利用矢量网络分析仪测试了样品在8.2～12.4GHz频率范围的微波介电常数,10wt%PTFE样品显示了最大的介电常数实部ε′、虚部ε″和损耗角正切tanδ。

N-doped SiC powders were prepared by combustion synthesis using silicon powder and carbon black as starting materials, with α-Si 3 N 4 as solid nitrogen dopant and polytetrafluoroethylene (PTFE) as the chemical activator, and then the products were characterized by X-ray diffraction and scanning electron microscope. Results show that prepared β-SiC has better purity and particle morphology when the amount of PTFE is 10wt%. The permittivities of as-prepared samples were determined by vector network analyzer in the frequency range 8.2～12.4 GHz. The sample with 10wt% PTFE reveals the greatest values in the real component ε′ and imaginary component ε″ of permittivity and dielectric loss tanδ in all three samples.