SiO_2纳米壳的厚度对羰基铁/SiO_2核壳复合粒子的性能影响

Properties of Fe/SiO_2 Core-shell Composite Particles with Different Nanoshell Thickness

以聚乙烯吡咯烷酮作表面改性剂,用溶胶-凝胶法,通过控制反应时间,在羰基铁粒子表面均匀快速地包覆不同厚度的SiO_2纳米壳层,并研究了SiO_2纳米壳层厚度对羰基铁/SiO_2核壳复合粒子的抗热氧化性能、静磁性能、微波介电常数和吸波性能的影响．结果表明：增加SiO_2纳米壳层的厚度,羰基铁/SiO_2核壳复合粒子的抗热氧化能力提高,比饱和磁化强度出现最大值,矫顽力和剩余磁化强度出现最小值,微波介电常数单调降低；用其制备的吸波涂层材料在壳层厚度为15nm时,反射损耗(?)-8dB的带宽达到最大值,超过10GHz．

Using a sol-gel route with polyvinyl pyrrolidone as the surfactant, the carbonyl iron microparticles were uniformly and fleetly coated by SiO2 nanoshell, whose thickness was conveniently different by changing reaction time. The influences of shell thickness on the properties of the Fe/SiO2 core-shell particles were studied. The results show that increasing the thickness of SiO2 nanoshell （Dshell）, the anti-oxidation property of the Fe/SiO2 core-shell composite particles is obviously improved while microwave permittivity decreased monotoneously. The saturation magnetization shows a maximum value while both the coercivity and remnant magnetization show minimum values at Dshell=15nm. Meanwhile, the radar absorbing coating based on the Fe/SiO2 core-shell composite particles with Dshell=15nm shows a maximum bandwidth of more than 10GHz, in which the reflective loss is less than -8dB.