高磁导率大损耗六角铁氧体材料的研究

【作者】 陈耿；

【导师】 谢建良；

【作者基本信息】 电子科技大学 ， 材料物理与化学， 2005， 硕士

【摘要】 本文研究了W 型Ba (Zn_1-xCo_x)₂Fe₁₆O₂₇ 和Z 型Ba₃(Zn_1-xCo_x)₂Fe₂₄O₄₁的基本电磁性能和电磁波吸收特性。实验过程中,利用氧化物工艺制备六角铁氧体样品,并通过BST、Nd₂O₃ 和Nb₂O₅ 等杂质的掺杂,改善了材料的电磁性能及电磁波吸收性能, 并测试了材料的复数磁导率μr、介电常数εr及比饱和磁化强度σs等电磁参数和反射率R（dB）,取得了一些具有实际意义的结果。1. 对于W 型六角铁氧体Ba (Zn_1-xCo_x)₂Fe₁₆O₂₇,当x=0.30,烧结温度为1300℃时,所得样品在8GHz 时磁导率及损耗最大。2. 对W 型六角铁氧体分别进行了Nd₂O₃ 和BST 的掺杂,结果表明, Nd₂O₃ 掺杂在W 型六角铁氧体中,会降低材料的磁导率及损耗;而BST 掺杂, 则可以增大磁导率及损耗,其中掺杂量为1%时,样品的μr′超过2, μr′′超过1.2。3. 在采用粉体工艺制备的Z 型六角铁氧体(Ba₃(Zn_xCo_1-x)₂Fe₂₄O₄₁)中,当x=0.7 时,烧结温度为1280℃时,所得样品在小于2GHz 时磁导率及损耗最大;。4. 在采用粉体工艺制备的Z 型六角铁氧体样品,当掺杂Nd₂O₃,可以增大样品的磁导率及损耗。5. 对于采用块材工艺制备的Z 型六角铁氧体样品,探索性的进行了稀土Nd₂O₃ 或Nb₂O₅ 掺杂,结果表明稀土Nd₂O₃ 或Nb₂O₅ 的掺杂能有效的提高材料的磁导率及损耗,其中掺杂Nd₂O₃0.3%, μi′达到25。6. 对以上掺杂或取代后的W 型和Z 型材料的反射率曲线进行理论设计,其结果表明,吸收峰移动规律和共振峰相同,并随材料厚度增加移向低频;另外通过对比,掺杂BST1%,厚度为3mm 的W 型六角铁氧体在8～12GHz 的反射率比未掺杂的材料要高8dB 以上,为提高材料在该频段的吸收性能提供了新的途径,在军民用领域具有广泛的应用前景。7. 通过对比W 型复合材料仿真结果与实际测试结果,验证了仿真的可行性和正确性。更多还原

【Abstract】 In this paper, the electromagnetic and absorption properties of polycrystalline hexagonal ferrites, Ba(Zn_1-xCo_x)₂Fe₁₆O₂₇ （W-type） and Ba₃(Zn_1-xCo_x)₂Fe₍24_O41 （Z-type） have been investigated. The samples were prepared by the usual ceramic sintering, and the parameters such as complex permeability μr、complex permittivity εr and reflection loss R（dB） were tested, and some good results were obtained. 1. It was proved that μr of Ba (Zn_1-xCo_x)₂Fe₁₆O₂₇ is the max and the frequency is the least. when x=0.30 and the sintering temperature is 1300℃. 2. Effects of Nd₂O₃ and BST additive on the W-type ferrite was studied. With the increasing of Nd₂O₃ content, μrof W-type ferrite decreased. But with the increasing of BST content, μr、εrof W-type ferrite increase. 3. It was proved that μr of Ba₃(Zn_xCo_1-x)₂Fe₂₄O₄₁ is the max and the frequency is the least. when x=0.7 and the sintering temperature is 1280℃. 4. Effects of Nd₂O₃ additive on the composite Z-type hexaferrite was studied. It was proved that μrof Z-type ferrite increased with the increasing of x. 5. Effects of Nd₂O₃ or Nb₂O₅ additive on the Z-type ferrite was studied. With the increasing of Nd₂O₃ or Nb₂O₅content, μr、εrof Z-type ferrite increase. 6. According to results of the calculated reflection loss（dB）, the absorption peak shifted to a lower frequency with increasing the thickness, the tested curve of R（dB） coincided with the calculated R（dB）, which means that the calculated reflection loss（dB） was right. In the rang of 8～12GHz, the R（dB） of W-type ferrite doping BST was above 8dB lower than W-type ferrite without BST with the same thickness of 2.5mm, which provides a new approach to improve the absorption properties in the rang. This material has a bright application future in the civilian and military field. 7. according to comparing the simulation result and the real testing result, the simulation results is feasible and accurate.更多还原