AlN-W-CNTs复合陶瓷的微波衰减研究

The dielectric properties of AlN-W-CNTs composite ceramics

以AlN、CNTs和W粉为原料,采用放电等离子烧结技术,在1 700℃、30 MPa的工艺条件下制备了AlN/W/CNTs复合陶瓷。采用扫描电镜、能谱分析仪、安捷伦LCR自动测试仪等对复合陶瓷的微观组织、介电常数、微波损耗进行了表征,研究了影响复合陶瓷微波损耗性能的因素。结果表明,高能球磨混粉能有效的改善CNTs在基体中的分散均匀性;W含量的增加能有效促进复合陶瓷的烧结致密化;随着CNTs含量的增加,材料的介电损耗降低,介电常数增加;CNTs含量在1%体积分数,1 MHz以下的损耗角正切tanδ≥0.04。

AlN-W-CNTs composites using AlN,W and CNTs as the raw materials were prepared by SPS at the temperature of 1 700 under pressure of 30 MPa in a vacuum atmosphere without any sintering additives.The microstructure,dielectric constant and loss tangent of the ceramics were characterized by scanning electron microscopy and Agilent4284 A LCR automatic tester respectively.The results show that the relative densitiy of sintered ceramics increase with the W content increasing.The dielectric constant increase but the loss tangent decrease with the CNTs content increasing.The loss tangent is more than 0.04 with the CNTs content of 1% and frequency of less than 1 MHz.