表面改性对FeSiCr磁性吸波材料耐温吸波性能的影响

Effects of Surface Modification on the Heat-Resistant and Absorbing Properties of FeSiCr Alloy

通过球磨工艺,以硅烷偶联剂KH560对FSC(FeSi_7Cr_3)磁粉进行表面改性,采用扫描电镜(SEM)、热重(TG)分析,研究了表面改性前后FSC磁粉的微观形貌及热分析性能。用矢量网络分析仪测量吸波材料的电磁参量,发现球磨后磁粉颗粒形貌由球形变为扁平片状。TG结果表明,表面处理后试样在900℃氧化4h后仍然具有较好的抗氧化性。电磁参量结果表明,高温氧化后试样的介电参数有所降低。高温氧化结果表明,利用硅烷偶联剂KH560对FSC磁粉进行表面改性,能够提高吸波材料的耐高温性能。表面改性后的FSC磁粉在高温处理后仍然保持良好的吸波性能。在氧化温度为700～900℃时,反射损耗峰由4GHz向高频偏移到6GHz附近,反射损耗性能依旧保持在15dB左右,可见表面改性吸波材料表现出较为良好的抗氧化吸波特性。

The surface modification was used on FSC(FeSi7Cr3)magnetic powder with the coupling agent KH560 through the ball milling process.The microstructure and thermal analysis properties of the surface modification layer were analyzed by scanning electron microscopy(SEM)and thermogravimetric analysis(TG).The vector network analyzer was adopted to measure the electromagnetic parameters of the microwave absorbing materials.The results show that the shape of the magnetic powder particle is changed from spherical to flat after ball milling treatment.TG results show that the sample after surface treatment still has good oxidation resistance after oxidation for 4 hat 900℃.The electromagnetic parameter results show that the dielectric parameters of the sample after high temperature oxidation are decreased,which is conducive to improving the dielectric matching of microwave absorbing materials.The high-temperature oxidation results show that the surface modification of FSC magnetic powder with coupling agent KH560 can improve the high-temperature resistance of the microwave absorbing material.The surface-modified FSC magnetic powder still maintain good microwave absorbing properties after high temperature treatment.At the oxidation temperature of 700~900℃,the reflection loss peak is shifted from 4 GHz to high frequency near 6 GHz,and the reflection loss performance is kept at approximately 15 dB.The surface-modified absorbing material shows the satisfied oxidation resistance and microwave absorbing characteristics.