空芯玻璃微球表面改性及其介电性能研究

Surface Modification on SiO_2 Microbubble and Its Electromagnetic Properties

采用直流磁控溅射法对空芯二氧化硅微球表面镀Ni薄膜,利用扫描电镜对镀Ni膜微球形貌进行观察。结果表明获得了金属Ni包覆的玻璃微球。将镀Ni膜微球与高分子粘合剂混合制得人工介质材料,在一定频率范围内,测试其介电常数,并采用有效媒质理论对测试结果进行了分析。研究结果表明,在体积分数一定的情况下,介质材料的有效介电常数eeff随膜厚的增加而增加。eeff随着镀Ni微球体积分数的增加而增加,其实验值与有效媒质理论的C M公式计算值较好地吻合。

Magnetron sputtering was employed to sputter nickel on the surface of SiO_2 microbubbles. SEM analysis indicates that nickel could be coated on the surface of microbubbles. Effective permittivity(e_(eff)) of microbubble-polymer mixture was measured at the certain frequency range. The results show that e_(eff) of mixture increases with the thickness of metal layer and the volume percentage of coated microbubbles, which accord with the calculation result by C-M equation of effective medium theory (EMT).