兰州大学机构库 >物理科学与技术学院
平面各向异性稀土铁基化合物微粉复合材料的微 波磁性及微波吸收性质
Alternative TitleMicrowave magnetic and absorption properties of Fe-based planar anisotropy rare earth compound micropowder composites
左文亮
Thesis Advisor李发伸
2011-04-06
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name博士
Keyword复数磁导率 微波吸收 稀土铁基化合物 Snoek 极限 平面磁晶各向异性 Sm 替代 Nd
Abstract

传统的微波磁性材料由于Snoek 极限限制, 难以满足日益发展的应用型高频磁性材料性能的需要。 本论文中研究的具有平面磁晶各向异性的稀土铁基化合物微粉能够突破Snoek 极限,可以在GHz得到更大的磁导率,从而成为新的高频微波吸收材料。
根据这一原理, 使用电弧熔炼制备了具有平面磁晶各向异性的稀土铁基化合物R2Fe17N3-δ(R=Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉。将微粉样品与环氧树脂或石蜡混合制备复合材料,对于石蜡复合材料做了进一步的取向优化。 然后使用矢量网络分析仪同轴法测量了它们在0.1-18 GHz 频段的复数磁导率。讨论了材料的本征磁导率及微波吸收性质。得到以下结论:
(1) (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉制备的最佳球磨时间是 12 小时。(2)球磨过程中加入偶联剂能防止微粉氧化。(3)稀土铁基化合物 R2Fe17N3-δ(R=Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉复合材料出现微波吸收峰时对应的峰值频率,厚度以及电磁参数满足 1/4 波长关系。(4)稀土铁基化合物 R2Fe17N3-δ(R= Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉复合材料最大反射吸收都出现在相对输入阻抗 Zin/Z0 等于 1 时。(5)稀土铁基化合物 R2Fe17N3-δ(R= Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.2), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉/环氧复合材料最小反射吸收值都小于-30dB。(6)通过比较稀土铁基化合物 R2Fe17N3-δ R= Nd,Ce,Pr),(Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉石蜡复合材料和环氧复合材料的微波磁性及微波吸收性质, 我们发现环氧复合材料比石蜡复合材料具有更低的介电常数,更高的磁导率。(7)取向能提高 R2Fe17N3-δ(R= Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58)微粉复合材料的磁导率以及改善阻抗匹配。(8) Pr2Fe17N3-δ微粉氮化的最佳温度是 500 oC。(9)相比于 Co2Z 复合材料,稀土铁基化合物 R2Fe17N3-δ(R= Nd, Ce, Pr),(Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.3)微粉/环氧复合材料具有更大的初始磁导率和更低的匹配厚度。(10)通过稀土替代能够提高稀土铁基化合物 (Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), (Nd1-Smx)2Fe14B(0.12≤x≤0.58)微粉复合材料的微波磁性及微波吸收性能。

Other Abstract

It is difficult to improve the capability of traditional microwave magnetic materials owing to the Snoek’ limit. This paper researched planar anisotropy Fe-based rare earth compounds which can exceed the Snoek’s limit and obtain larger complex permeability in the GHz ranges. Therefore, planar anisotropy Fe-based rare earth compounds are an excellence microwave absorption material for applications.
In this work, the Fe-based rare earth compound micropowders R2Fe17N3-δ(R=Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ (0≤x≤0.4), (Nd1-xSmx)2Fe14B(0.12≤x≤0.58) were prepared by arc melting method. The composites were prepared by mixing the compound particles with paraffin wax or resin epoxy, in addition, the aligned paraffin composites were also prepared. The complex permeability of the composites was measured in the frequency range of 0.1-18GHz using a vector network analyzer. The properties of intrinsic permeability and microwave absorption were discussed. The main results were shown as follows:
(1) The optimal milled time for prepared (Nd1xSmx)2Fe14B(0.12≤x≤0.58) micropowders is 12 h. (2) The coupling agent can prevent the oxidation of Fe-based rare earth compound particles.(3) The microwave absorption peaks is appearance for all the R2Fe17N3-δ (R=Nd, Ce, Pr),(Nd1-xSmx)2Fe17N3-δ(0≤x≤0.4), and (Nd1-xSmx)2Fe14B(0.12≤x≤0.58) composites when the frequency of peak, thickness and electromagnetic parameter satisfy the 1/4 wavelength relation. (4) The microwave absorption of all the R2Fe17N3-δ (R=Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ (0≤x≤0.4), and (Nd1-xSmx)2Fe14B(0.12≤x≤0.58) composites are maximal when Zin/Z0 equal to 1(5) The minimum microwave absorption values for all the R2Fe17N3-δ (R=Nd, Ce, Pr), (Nd1-xSmx)2Fe17N3-δ (0≤x≤0.2), and (Nd1-xSmx)2Fe14B(0.12≤x≤0.58) composites are smaller than -30dB. The microwave absorption value of(Nd1-xSmx)2Fe17N3-δ (x=0.3) is smaller than -25dB.(6) The properties of complex permeability and microwave absorption for both the R2Fe17N3-δ (R=Nd, Ce, Pr) and (Nd1-xSmx)2Fe14B(0.12≤x≤0.58) composites were researched, and the results shows that the resin composite has lower permittivity, higher permeability than that of paraffin composite.(7) The aligned composite shows higher permeability and lower reflectivity than that of unaligned one.(8) The optimal nitrogenation temperature of prepared Pr2Fe17N3-δ particles is 500 oC.(9) R2Fe17N3-δ (R=Nd, Ce, Pr) and (Nd1-xSmx)2Fe17N3-δ (0≤x≤0.3) composites show higher intrinsic permeability and smaller matching thickness than that of Co2Z composite.(10) Sm substitute Nd can improve the complex permeability and microwave absorption properties of (Nd1-xSmx)2Fe17N3-δ (0≤x≤0.4) and (Nd1-xSmx)2Fe14B (0.12≤x≤0.58) composites.

URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229493
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
左文亮. 平面各向异性稀土铁基化合物微粉复合材料的微 波磁性及微波吸收性质[D]. 兰州. 兰州大学,2011.
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