本文采用水热合成法,以(NH_4)_2S_2O_8作氧化剂,以MnSO_4为锰源,在不同水热反应时间下制备了不同晶体结构和形貌的二氧化锰.利用X射线粉末衍射(XRD),扫描电子显微镜(SEM)和透射电子显微镜(TEM)对产物进行成分、晶型和形貌进行分析,并通过电磁参数的测试对产物的电磁特性以及电磁波损耗机制进行讨论.结果表明,水热反应时间由1h逐渐增加到48h后,二氧化锰晶体结构由纯γ型逐渐转变为纯β型,中间产物为γ、α和β的混合体,二氧化锰的形貌也由球状经团絮状后逐渐转变为直径约为5-10nm纳米线状.复介电常数随反应时间增加而增加,复磁导率却正好相反,由此最后分析了二氧化锰的电磁波损耗机制.
MnO_2 with different morphology and crystal structure were prepared via a low-temperature hydrothermal method in stainless-steel autoclave at 120℃ and different dwell time, which (NH_4)_2S_2Os is oxidizing agent and MnSO_4 is Mn source. The products were characterized by powder X-ray diffraction (XRD) , scanning electron microscopy (SEM) and transmission electron microscope (TEM) , and the electromagnetic properties and microwave loss mechanism of as-obtained MnO_2 were firstly reported. The results show that the dwell times play a crucial role in the phase purity, the crystal structure, the morphology and the electromagnetic properties of the products. The as-prepared MnO_2 transformed gradually from γ-MnO_2 to α-MnO_2 and β-MnO_2 and became finally a pure tetragonal phase of β-MnO_2, and the morphology changed also from microspheres with flocculus on the surface into dispersive nanorods with the increase of the dwell times from 1h to 48h. The real and imaginary parts of the complex permittivity of as-prepared MnO_2 increased orderly with rising dwell times, and the complex magnetic permeability were on the contrary. Lastly, the microwave loss mechanism of as-obtained MnO_2 was analysed.
参考文献
| [1] | Guangcheng Xi;Yiya Peng;Yongchun Zhu;Liqiang Xu;Wanqun Zhang;Weichao Yu;Yitai Qian .Preparation of β-MnO_2 nanorods through a γ-MnOOH precursor route[J].Materials Research Bulletin: An International Journal Reporting Research on Crystal Growth and Materials Preparation and Characterization,2004(11):1641-1648. |
| [2] | Lili Li;Ying Chu;Yang Liu .Synthesis and shape evolution of novel cuniform-like MnO_2 in aqueous solution[J].Materials Letters,2007(7):1609-1613. |
| [3] | 葛副鼎;朱静;陈利民.吸波剂颗粒形状对吸波材料性能的影响[J].宇航材料工艺,1996(05):42-49. |
| [4] | 张德勇;程海峰;唐耿平 等.吸波剂形状对雷达吸波材料性能的影响研究[J].功能材料,2007,38(A8):2963-2965. |
| [5] | Yuan ZY.;Zhang ZL.;Du GH.;Ren TZ.;Su BL. .A simple method to synthesise single-crystalline manganese oxide nanowires[J].Chemical Physics Letters,2003(3-4):349-353. |
| [6] | Gao YQ;Wang ZG;Wan JX;Zou GF;Qian YT .A facile route to synthesize uniform single-crystalline alpha-MnO2 nanowires[J].Journal of Crystal Growth,2005(3/4):415-419. |
| [7] | 李青,胡云楚,汤林.二氧化锰超细粉体的制备及其电化学性能[J].材料热处理学报,2007(03):31-34. |
| [8] | 杨镇宇,王庚超,李星玮.层状二氧化锰/苯胺-邻甲氧基苯胺共聚物复合材料的制备与性能研究[J].功能材料,2006(12):1906-1909. |
| [9] | HONGTAO GUAN;SHUNHUA LIU;YANBO ZHAO;YUPING DUAN .Electromagnetic Characteristics of Nanometer Manganese Dioxide Composite Materials[J].Journal of Electronic Materials,2006(5):892-896. |
| [10] | Guan H;Zhao Y;Liu S;Lv S .Application of manganese dioxide to electromagnetic wave absorber: effective permittivity and absorbing property[J].The European physical journal. Applied physics,2006(3):235-239. |
| [11] | H E Wang;D Qian .Synthesis and electrochemical properties of α-MnO_2 microspheres[J].Materials Chemistry and Physics,2008,109:399-403. |
| [12] | 郝洪顺,付鹏,巩丽,王树海.二氧化硅体系透波材料的透波机理及研究现状[J].佛山陶瓷,2007(03):33-37. |
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