【作者】 阚茹心； 顾家琳； 康飞宇；

【Author】 KAN Ru-xin, GuJia-lin, KangFei-yu (Material Science and Engineering Department, Advanced Material Laboratory of Ministry of Education, Tsinghua University,Beijing 100084, China)

【机构】 清华大学材料科学与工程系教育部先进材料实验室；

【摘要】 通过溶胶凝胶法制备了不同Co含量的Y型六角钡铁氧体纳米粉末Ba2CoxZn2-xFe12O22．透射电镜 (TEM)和X光衍射分析(XRD)结果表明,采用二阶段热处理法在450℃下热处理4h,再升温至1050℃热处理 4h可以获得纳米Y型六角铁氧体．将各铁氧体和石蜡按照65:35的比例均匀混合制成复合材料,测试各复合材料在2-18GHz频段内的复介电常数和复磁导率, 计算其介电损耗角和磁损耗角,并且通过其电磁参数模拟计算出各复合材料在微波频段的反射率曲线,由结果可知:各样品的磁导率实部随频率增加而减小,随频率变化的趋势基本类似．各样品磁导率虚部最大值对应的频率随其成分中Co含量增加而提高,磁导率虚部最大值在0．5-0．8之间,Co1．2的磁导率虚部在12GHz达到 0．8,样品磁损耗角随频率变化规律与磁导率虚部相似, Co1．2的磁损耗角在11GHz达到0．7:各个铁氧体微波吸收峰对应的频率随着其成分中Co含量的增加而向高频移动,其最大吸收峰值随Co含量增加先增加后减小, 在各样品中,Co1．2微波吸收能力最强,吸收峰所在频率为16GHz,强度达-26dB,同时具有最大的有效带宽8GHz。更多还原

【Abstract】 Y-type hexaferrites Ba2CoxZn2-xFe,2O22(x=0.2,0.4,0.6,0.8,1.0,1.2,1.4) were synthesized through sol-gel process; results of TEM and XRD reveal that the Y-type hexaferrite nano-particles can be obtained with two-step heat treatments at 450℃ for 4hours and then at 1050℃ for 4 hours. Compound materials with 65wt% hexaferrites dispersing in paraphin were prepared and the complex permeability and permittivity spectrums within the range of 2-18GHz for the compound materials were detected by using the Vector Network Analyzer, and the electromagnetic wave absorption capacity of these compound materials were also calculated theoretically. The results show that the frequency corresponding to the peak of μ" > tg ε m of composites enhances with the increase of x. The max value of μ " is between 0.5 and 0.8, and when x= 1.2, the μ" reaches 0.8 at 12GHz, and tg ε m reaches 0.7 at 11 GHz. Absorption peak of composites shift to high frequency with the increase of x, and the absorptivity varies with x. When x= 1.2, the max absorptivity within 2- 18GHz reaches 26dB, and the effective range reaches 8GHz.更多还原