【摘要】 通过碳热还原法合成了纳米 Si C粉并对其在 8.2～ 12 .4GHz频率范围的介电参数进行了测量。通过改变铝含量和反应气氛分别得到了 β,12 H和 2 1R型碳化硅粉。β- Si C粉具有比 α- Si C粉高得多的相对介电常数ε′r=30～ 5 0 )和介电损耗角正切值 (tgδ =～ 0 .7)。虽然 Al和 N的固溶将 Si C粉的电阻率减小到 10 2 Ω· cm的量级 ,但其相对介电常数和介电损耗却并没有增加 ,反而随 Al含量的增加降低更多还原

【Abstract】 The nano sized SiC powders were synthesized with the carbothermal reduction method and their dielectric properties were also investigated in the 8 2 ~ 12 4GHz frequency range The polytypes of SiC are changed from β type (3C) to α type (12H and 21R) by varying the aluminum contents and the reaction atmospheres The β SiC powder have much higher relative permittivity (ε ′ r = 30~50) and loss tangent (tgδ =~0 7) than α SiC powders Though the doping of Al and N decreases the resistivities of SiC to the order of 10 2 Ω·cm, the relative permittivity and loss tangent don′t increase The relative permittivity and loss tangent decrease with the rising of Al contents更多还原