ALN-SiC复合陶瓷衰减性能.docVIP

AlN-SiC复合陶瓷的微波衰减性能 张玉利， 贾成厂*， 高鹏 北京科技大学材料科学与工程学院，北京，100083 摘要：以氮化铝，纳米碳化硅为原料，无烧结助剂， 1600℃，30MPa，保温5min，SPS），制备了AlN-SiC复合陶瓷。利用扫描电镜，能谱分析仪，XRD，安捷伦4284ALRC阻抗分析仪等对其致密度，显微结构，表面成分，生成的主要物相，介电损耗和介电性能进行分析。结果表明，AlN-SiC复合陶瓷的致密度在93%以上，物相主要有作为原料的AlN和β-SiC，以及烧结之后生成的2H-SiC和Fe5Si3，随着SiC含量的增加，材料的介电损耗，介电常数相应增加，SiC含量在30%-40%wt之间，1MHz以下的损耗角正切tanδ≥0.3。SiC具有较强的吸波性能。相同含量的碳化硅，材料的介电常数和介电损耗随着频率的增加而降低。 关键词：氮化铝，纳米碳化硅，SPS，Study on Performance of AlN-SiC Composite Ceramics with Attenuation Characteristics ZHANG Yuli1）， J Chengchang1）*，G Peng1） College of Materials Science and Engineering , Beijing University of Science and Technology, Beijing, 100083) Abstract：AN-SiC composites with AlN and nanoβ-SiC as raw materials were prepared by SPS at the temperature of 1600, 30MPa uniaxial pressure and soaking time for 5min without any sintering additives in a vacuum atmosphere. The microstructure, the produced phases，dielectric constant and loss tangent of the ceramics were characterized by scanning electron microscopy，XRD, and Agilent4284A LCR automatic tester respectively. The results show the loss tangent and dielectric constant are increased by the SiC content increasing. The loss tangent is more than 0.3 with the SiC content ranging from 30-40wt%. It’s indicated that nanometer SiC has strong absorbing property. We also know that the dielectric constant and dielectric loss are deduced by the frequency increasing with the same content of silicon carbide. In addition to AlN and beta SiC, 2H-SiC and Fe5Si3 are generated with the aid of the XRD analysis. The relative densities of sintered ceramics are in excess of 93%. Key words: aluminum nitride; nano silicon carbide; SPS；dielectric loss 基金项目：国际合作项目，功率微波电真空器件用高热导陶瓷材料，2010DFR50360 通信作者：贾成厂，教授，博士生导师，主要从事复合材料，粉末冶金的研究 E-mail：jcc@ustb.edu.cn 引言 吸波材料广泛应用于军事领域，主要用作大功率微波管里面的衰减材料，其主要作用是对信号的全吸收、降低反射和有选择的抑制各种模式的杂波，从而确保给定的高频参量,提高器件的稳定性[1]。这种微波衰减材料要求具有较高的热导率，高温稳定性和足够高的衰减性。目前国内常用的微波衰减材料为BeO基复合衰减陶瓷和渗碳多孔氧化铝，BeO因其毒性限制其发展，而多孔氧化铝真空放气量大，热导率低，强度不够也不能满足微波衰减材料的使用需求[2]。而AlN具有较