Si、Cu、Ti添加对MnAl基合金微波吸收性能的影响

Effect of Si, Cu, Ti substitution on microwave absorbing properties of MnAl powder

采用真空电弧熔炼和高能球磨工艺制备了MnAl基合金粉体,使用SEM、XRD和网络矢量分析仪研究Si、Cu、Ti元素添加对MnAl合金粉体组织结构和微波性能的影响。结果表明:加入Cu、Ti不改变Al_8Mn_5合金粉体的相组成,均为Al_8Mn_5单相粉体,加入Si的Al_8Mn_5合金粉体相组成除有Al_8Mn_5相外,还有少量的Si和MnSi相。加入Si、Cu、Ti均可使Al_8Mn_5粉体开始出现反射损耗峰的频率向低频方向移动。当涂层厚度为2.0 mm时,(Al_8Mn_5)_(0.96)Cu_(0.04)合金粉体的反射率最小值达到约–29.9 dB,并具有很好的频宽效果。

MnAl alloy powder was prepared by the process of vacuum levitation melting and high-energy ball milling.The effect of the Si, Cu, Ti substitution on the morphology, phase structure and microwave absorbing properties of thepowder were analyzed by scanning electron microscope （SEM）, X-ray diffraction （XRD） and vector network analyzer. Theresults show that the prepared powders are mainly composed of Al8Mn5 single phase when added with Cu or Ti. However,the phase composition of powders includes Al8Mn5 phase besides a spot of Si and MnSi phases when added with Si. Theaddition of Si, Cu, or Ti can cause the reflection loss peak of Al8Mn5 powder to move toward low frequency region at thebeginning. The （Al8Mn5）0.96Cu0.04 powder with a coating thickness （d） of 2.0 mm has a minimum reflectivity of about –29.9dB and better bandwidth effect.