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采用低温水热合成法,以(NH4)2S2O8作氧化剂,以MnSO4·H2O为锰源,在高压反应釜中加热120℃并保压48h制备了β-MnO2纳米棒。利XRD,SEM,TEM和振动样品磁强计(VSM)对产物进行表征,并就产物的电磁特性和多极化损耗机制进行研究。结果表明,纳米粉体产物是直径为50～70nm,长度约为几个微米并具有四方晶体结构的β-MnO2纳米棒,同时产物表现出超顺磁性特征。β-MnO2纳米棒具有优异的电磁波损耗特性,厚度为1mm的试样其最大反射损耗在18GHz能达到-8.1dB,优于-5dB的有效吸收带处于15.7～18GHz宽频段内;2mm厚的试样在9.8GHz其反射损耗达到-25dB,并且优于-5dB的有效吸收带处于8～12.8GHz。
The β-MnO2 nanorods were prepared by using low-temperature hydrothermal synthesis method with (NH4) 2S2O8 as oxidant, MnSO4 · H2O as manganese source, heating in an autoclave at 120 ℃ for 48h. The products were characterized by XRD, SEM, TEM and vibrating sample magnetometer (VSM). The electromagnetic properties and multi-polarization loss mechanism of the products were studied. The results show that the nano-powder product is β-MnO2 nanorods with diameter of 50-70nm, length of about several microns and tetragonal crystal structure, and the product shows superparamagnetism. β-MnO2 nanorods have excellent electromagnetic wave loss characteristics. The maximum reflection loss of the sample with the thickness of 1mm can reach -8.1dB at 18GHz. The effective absorption band better than -5dB is in the 15.7-18GHz wide band. The 2mm thick test It has a reflection loss of -25 dB at 9.8 GHz and an effective absorption band of better than -5 dB at 8-12.8 GHz.