【摘要】 目的提高碳化硅微粒的微波吸收性能。方法利用改进的化学镀法,以硫酸钴和硫酸亚铁为主盐,次亚磷酸钠为还原剂,施镀温度为50℃,使用机械搅拌和超声分散相结合的方法,在预处理后的微米碳化硅颗粒表面沉积钴铁合金。通过X射线衍射仪(XRD)、X射线能谱仪(EDS)和扫描电子显微镜(SEM)分别对化学镀前后材料的结晶状态、组成成分和形貌特征进行了表征;利用矢量网络分析仪对化学镀前后材料在2～18GHz频率范围内的电磁性能进行了测试,并通过计算得到了材料微波反射率损耗。结果钴铁合金呈微球状均匀沉积在碳化硅表面,有效地改善了碳化硅材料的电磁性能和微波吸收性能。碳化硅的介电常数虚部存在界面极化和缺陷极化两个弛豫峰(9.1、13.8 GHz),而沉积钴铁合金后,碳化硅材料Co-Fe/Si C增加了两个弛豫峰:介电弛豫峰(11.7 GHz)和磁弛豫峰(12.6 GHz)。正是由于Co-Fe合金对微波信号的介电弛豫和磁弛豫,有效提升了材料的吸波性能。当吸波层厚度为2.4 mm时,反射率在10 dB以上的吸收带宽达到3.8 GHz,20 dB带宽可以达到1.5 GHz。当吸波层厚度为2.3 mm时,频率为12.7 GHz时达到最大吸收峰值–43 dB。结论在碳化硅材料表面沉积钴铁合金是一种有效改进材料微波吸收性能的方法,且该材料是一种高效、宽频的微波吸收材料。更多还原

【Abstract】 The work aims to improve microwave absorption properties of silicon carbide microparticles. Through improved chemical plating method, ferrocobalt alloy was deposited on the surface of SiC microparticles with CoSO4 and FeSO4 as the main reactants and NaH2 PO2 as reducing agent by combining mechanical agitation and ultrasonic dispersion at the plating temperature of 50 ℃. The crystal state, composition and morphology of the materials before and after plating were characterized by X-ray diffractometer(XRD), X-ray energy spectrometer(EDS) and scanning electron microscope(SEM). The electromagnetic properties of the materials were tested by vector network analyzer in the frequency range 2～18 GHz, and the microwave reflection loss was calculated. Ferrocobalt alloy was uniformly deposited on the surface of silicon carbide microparticles, which effectively improved the electromagnetic properties and microwave absorption of silicon carbide. There were two relaxation peaks of interfacial polarization(9.1 GHz) and defect polarization(13.8 GHz) in the permittivity imaginary part of silicon carbide, while two relaxation peaks of Co-Fe/SiC material were produced after the deposition: dielectric relaxation peak(11.7 GHz) and magnetic relaxation peak(12.6 GHz). The dielectric and magnetic loss of CoFe alloy to microwave signal effectively improved the absorption properties of the material. When the thickness of the absorbing layer was 2.4 mm, the absorption bandwidth with reflection loss 10 dB reached 3.8 GHz and 20 dB bandwidth could reach 1.5 GHz. When the absorbing layer thickness was 2.3 mm, the value of the maximum absorption peak was –43 dB at the frequency of 12.7 GHz. The deposition of ferrocobalt alloy on the surface of silicon carbide is an effective method to improve the microwave absorption performance of the material, and this material is an efficient broadband microwave absorbing material.更多还原