【作者】 张川；

【导师】 宋申华；

【作者基本信息】 哈尔滨工业大学 ， 材料加工工程， 2008， 硕士

【摘要】 微波吸收材料是一种重要的功能材料,它在军事技术、信息和环保科学领域获得广泛的应用和发展。近年来,随着电子技术的迅速发展,电磁波辐射的危害性越来越得到人们的高度重视,因此如何有效防止电磁波辐射的干扰,已经成为人们关心的问题。铁氧体具有优良的吸波性能,作为微波吸收材料能够减少目标物对雷达的散射,目前,吸波材料的研究正朝着吸收率高、涂层薄、吸收频带宽、质量轻、抗磨蚀及成本低的方向发展。通过在铁氧体中加入其它吸波介质组成复合吸收剂,可使电磁参数得到较好匹配。在实际使用中己经发现通过将铁氧体和其他多种材料复合能够提高材料的吸波性能。本文采用溶胶-凝胶法制备了纳米镍锌铁氧体。对镍锌铁氧体掺杂不同微量的稀土元素铈,发现微波吸收特性随掺杂稀土含量的不同而改变。在Ni_0.2Zn_0.8Fe_2-xCe_xO₄ （x = 0,0.01,0.03,0.07）四种不同掺杂铈的材料中,x=0.07的吸波性能最好,最高吸收值达到35.79dB,相对于x=0,0.03都有显著提高,x=0.01时吸波性能相对与x=0时（即未掺杂稀土时）又有所下降。添加稀土元素铈并不遵循随添量的增多吸波性能提高的原则,而是适量稀土元素铈的添加能有效提高材料吸波性能,过量或少量的添加都有减弱材料微波吸收特性的趋势。同时通过与国外先进吸波材料性能对比,发现吸波性能不仅与材料有关,还与贴片的内部结构设计有关。一般情况下,吸波性能随贴片厚度的增加而增加。更多还原

【Abstract】 Microwave absorbing material is a kind of functional material. It is applied and developed in military technology, information and environmental protection. The increasing environmental pollution from non-ionizing microwave irradiation due to the fast development in information and communication technology has received much attention. So how to prevent electromagnetic interference is an issue concerned.The ability of ferrite materials to absorb microwaves is well known. Ferrites have been used as absorbers in reducing back scattering from objects or radar targets. The recent development in absorber technology is to produce absorbers which are thin, flexible, strong and lowcost. These can be acheived by blending or mixing the pure ferrites with other non-magnetic oxides. The practice has found that changing the absorption characteristics of the pure ferrites may broaden the frequency of absorption.Nano-NiZn ferrite was produced by sol-gel method. Then different quantities of cerium were doped in nano-NiZn ferrite. It was found that the microwave absorption properties of ferrite change with changing quantity of rare earth. InNi_0.2Zn_0.8Fe_2-xCe_xO₄ （x=0, 0.01, 0.03, 0.07） four different materials, when the mol concentration of rare earth cerium is 7% （x=0.07）, the microwave absorption property is the best, while the microwave absorption property for x=0.01 is lower than that for x=0. These indicate that the absorption properties of these materials do not regularly change with the quantity of doped rare earth. Only doping a proper amount of rare earth cerium can improve microwave absorption properties of nano-NiZn ferrite, and doping more or less quantity of it is not favorable to improving microwave absorption property. In addition, some commercial products have been compared with ours, showing that not only the material but also the internal structure affect the absorption properties. In general, absorption properties of the nano-NiZn ferrite increase with the increase of its thickness.更多还原