热压烧结短切SiC_f／LAS复合材料的介电性能  

Dielectric Properties of Short Chopping SiC_f/LAS Composites by Hot-Pressing Sintering Method

作　　者：翟晓勇[1] 周万城[1] 罗发[1] 朱冬梅[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,西安710072

出　　处：《材料导报》2007年第10期129-131,共3页Materials Reports

基　　金：国家自然科学基金(50572090)

摘　　要：采用热压烧结法制备出致密的短切SiC_f增强LAS玻璃陶瓷复合材料,讨论了热压保温时间与纤维长度对复合材料介电性能的影响。结果表明,测试频率在8～12GHz之间,复合材料的复介电常数实部ε′由基体的7.6上升到10～100,虚部ε″由基体的0.34上升到60～140.介电损耗tgδ由基体的0.04上升到1～40,并具有明显的频散效应。当保温时间由10min增加到20min时,复合材料ε′增大,ε″与tgδ减小。保温时间10min时,随着纤维长度由2mm增加到4mm,复合材料ε′减小,ε″先减小后增大,而tgδ增大;保温时间20min时,随着纤维长度由2mm增加到4mm,复合材料ε′先减小后增大,ε″与tgδ则先增大后减小。复合材料具有成为电损耗型宽带吸波材料的潜力。The LAS glass-ceramic composites reinforced by short chopping SiC fibres of different lengths are prepared with hot-pressing sintering method in different hot-pressing time. In a range of 8-12GHz, the measurements of dielectric constant indicate that all the composite sample ε′,ε″ and tgδ increase 0. 3-13 times, 175-410 times and 24-1000 times, respectively, compared to those of the pure LAS matrix. All the composite samples＇ ε′ and ε″ show strong frequency dispersion effect. ε′Their increases while their ε″and tgδ decline with the increase of hot-pressing time from 10 to 20 minutes. The ε′, ε″and tgδ of the samples sintered for 10 and 20 minutes present different frequency dependences on diverse fiber lengths. The potential microwave absorption capability of the composites needs further studies.

关 键 词：复合材料 短切SiC纤维 LAS玻璃陶瓷 介电性能 

分 类 号：TB332[一般工业技术—材料科学与工程]