Fe3O4/Ni复合纳米颗粒的制备及其微波吸收特性

采用电爆炸技术，合成了粒径约为70nm 的Ni纳米颗粒，以3-巯基丙基三甲氧基硅烷偶联剂(MPTS)对Ni颗粒进行表面改性，利用共沉淀法对改性Ni颗粒进行包覆得到核-壳结构的复合纳米颗粒。将获得的复合纳米颗粒作为微波吸收剂， 并以不同比例分散到热固性酚醛树脂中，涂刷在200mm×200mm的金属板上，用RAM反射率远场RCS测量法研究了微波吸收特性。研究表明，核-壳结构Fe₃O₄/Ni复合颗粒作为微波吸收剂，在相同质量比条件下，其微波吸收性能明显优于纯Ni纳米颗粒或Fe₃O₄纳米颗粒的情况，并且在Fe₃O₄/Ni核-壳结构复合纳米颗粒中随着镍含量的提高，微波吸收增强，而随着Fe₃O₄含量的增加，微波吸收频段向高频段移动。

Preparation and properties of Fe3O4/Ni nanoparticles

The spherical nickel nanoparticles (an average diameter of 70 nm) were prepared by the wire electrical explosion method，Fe3O4 was coated on nickel to form the complete coverage by the co-precipitation method，and the silane coupling agent 3-mercaptopropyltrimethoxysilane (HS-(CH2)3Si(OCH3)3，MPTS) was used as a primer to improve the nickel surface.The as-synthesized  Fe3O4/Ni composite particles were uniformly dispersed into the phenolic cement， then the mixture was pasted on the metal plate with the area of 200 mm×200 mm as the test board.The test of microwave absorption was carried out by the radar-absorbing materials (RAM) reflectivity far field radar cross-section (RCS) method. The results show that as a microwave absorber，the properties of the  Fe3O4/Ni nanoparticles with core-shell structure are superior to those of Ni nanoparticles or Fe3O4 nanoparticles at the same mass quality ratios. Furthermore，with the content of Ni increasing，the microwave absorption performances of the as synthesized  Fe3O4 /Ni nanoparticles are enhanced. At the same time，the absorption frequency ranges will shift to the high frequency sections when the contents of Fe3O4  increase. 