采用真空悬浮熔炼和高能球磨工艺制备Al8Mn5合金粉体,使用XRD和网络矢量分析仪研究回火温度对粉体组织结构和微波吸收特性的影响。结果表明:低于或等于400℃回火处理的高能球磨Al8Mn5合金粉体主要由Al8Mn5单相组成,600℃回火处理后,粉体主要由Al8Mn5、Al2Mn3和Mn2O3相组成;随回火温度升高,Al8Mn5粉体电磁参数虚部的共振频率、损耗因子的峰值频率和吸收峰频率均向高频方向移动;400℃回火粉体具有最强的吸波能力,涂层厚度为2.0 mm时,其反射率最小值达到-37 d B。
采用真空悬浮熔炼和高能球磨工艺制备Mn-Al基合金粉体,使用XRD、SEM和网络矢量分析仪研究Ce含量对MnAl粉体组织结构和微波吸收特性的影响。结果表明:随着加入Ce含量的增加,AlMnCe粉体Al_8Mn_4Ce相随着增多,同时AlMnCe合金粉体复数介电常数虚部ε″和复数磁导率虚部μ″的共振峰频率及反射损耗峰频率均向低频移动;当涂层厚度为1.8 mm时,Al_8Mn_4Ce粉体的反射率最小值达到约–26.9 d B。
The composites of Ce-Co-based alloys doped with La content were fabricated via a vacuum arc melting method.The influences of La addition on microstructure,electromagnetic parameters,magnetic property and microwave absorbing property were measured by the corresponding equipment.The morphology characteristics manifest that all samples display sheet structure,and the average particle size of alloy powders increases with increasing La content The saturation magnetization(MS) decreases with increasing La addition as a whole.The minimum reflection loss(RL) of La0.4Ce1.6Co17 alloy powder about-42.29 dB can be obtained about-42.29 dB at 7.84 GHz with the matching thickness of 1.8 mm,and the corresponding effective bandwidth can achieve about 2.24 GHz.In addition,the minimum RL frequency moves towards a lower frequency region as the La content increases.The minimum RL of La0.3Ce1.7Co17alloy powder is less than-20 dB ranging from 1.2 to 2.4 mm in the whole 4-16 GHz.The maximum bandwidth can reach about 4.88 GHz at the given thickness of 1.2 mm.In general,these all indicate that the La addition is beneficial to improving the microwave absorbing performance in both effective bandwidth and absorption intensity.
采用真空悬浮熔炼和高能球磨工艺制备(Al8Mn5)95Ni5微粉,并与石蜡按不同体积浓度制成复合材料,采用网络矢量分析仪研究(Al8Mn5)95Ni5微粉体积浓度对复合材料微波吸收特性的影响。结果表明:随着(Al8Mn5)95Ni5微粉体积浓度的增加,复合材料的ε″共振峰频率、μ″共振峰频率和反射损耗峰频率均向低频方向移动;涂层厚度为1.5 mm时,(Al8Mn5)95Ni5微粉体积浓度为30%的复合材料具有最小的反射损耗峰值(约为-34.98 d B)和很好的频宽效果;增加复合材料中(Al8Mn5)95Ni5微粉体积浓度,被吸波涂层表面反射回去的电磁波会增多。
采用真空电弧熔炼和高能球磨法制备片状NdxCe2-xCo17合金粉末并且研究了Nd含量和匹配厚度对相组成、形貌、电磁参数和微波吸收性能的影响。结果表明,Nd0.3Ce1.7Co17粉末的最大反射率可以达到-32.36 d B,同时有效带宽能扩大4倍。此外,调整Nd含量能成功优化Ce2Co17合金粉末的微波吸收性能。随着Nd含量的增加,吸收峰有向低频段移动的趋势,并且当厚度为1.8mm时,Nd0.3Ce1.7Co17粉末在7.28 GHz处最大反射率可以达到-30.53 d B,并且有效带宽为2.24 GHz中,这表明Nd-Ce-Co合金在C波段是具有低厚度、宽频和高效等特点的理想吸收材料。
RE13Fe84Cr3(RE=Ce, Pr, Tb, Er) and Pr13-xFe84Cr3Tix(x=0, 2, 4, 6) alloy powders were prepared by arc smelting method and high energy ball milling technique. The phase structure and the morphology of the alloy powders were investigated by X-ray diffraction(XRD) and scanning electron microscopy(SEM), and their microwave absorbing properties were determined by a vector network analyzer. The results show that the alloys with light rare earths(Ce, Pr) have good low frequency absorbing property and those with heavy rare earths(Tb, Er) exhibit an improved high frequency absorbing property. The minimum refl ectivity at the absorbing peak frequency of RE13Fe84Cr3(RE=Ce, Pr, Tb, Er) are-9.49 d B at 5.76 GHz,-22.38 d B at 7.92 GHz,-18.52 d B at 11.68 GHz and-17.59 d B at 10.24 GHz, respectively. The absorbing bandwidth under-10 d B of the Pr13Fe84Cr3 powder was widened from 1.91 GHz to 3.89 GHz by adding 2% Ti, but the refl ectivity of the alloy was increased from-22.38 d B to-14.91 d B.
