W型六角晶系铁氧体制备及吸波特性研究

【作者】 丁丽；

【导师】 邓联文；

【作者基本信息】 中南大学 ， 凝聚态物理， 2011， 硕士

【摘要】 W型钡六角晶系铁氧体由于具有较高饱和磁化强度、强磁晶各向异性、良好化学稳定性等优点,已被广泛应用于微波器件及电磁波吸收领域。本文以W型六角晶系钡铁氧体Ba1Zn2Fe16027微波电磁特性为重点,研究了其成分、工艺参数以及离子掺杂对该类六角铁氧体材料电磁特性和吸波性能的影响,探讨了稀土离子掺杂对W型六角晶系钡铁氧体微结构和电磁特性的影响；并在W型六角晶系钡铁氧体微波损耗特性研究基础上,探讨了该类W型六角晶系钡铁氧体吸收剂与Fe基合金吸收剂复合后的电磁特性及吸波性能。使用改进的溶胶凝胶工艺,在煅烧阶段采用两部热处理法,即先预热一定时间,再升温煅烧,可以有效地降低六角晶系铁氧体W相的成相温度。研究离子取代掺杂对W型六角晶系钡铁氧体微结构和电磁特性的影响,首先用不同量的Co2+对B位的Zn2+进行取代,发现Co2+的掺杂量为O.9时吸波性能较高,吸收峰值达-33.6dB；进而研究在A4位和B位复合掺杂对W型六角晶系钡铁氧体微结构和电磁特性的影响,发现在A位以O.2的稀土La3+取代Ba2+,在B位以0.9 Co2+取代Zn2+时,W型BaLaCoZn六角铁氧体的吸波性能较好,峰值点达-39.6dB。基于制备的W型六角晶系钡铁氧体Ba1Zn2Fe16O27,研究了该类铁氧体吸收剂材料与磁性合金Fe85 Si1Al6 Cr8微粉材料的复合应用特性,发现磁性合金微粉与W型六角铁氧体的质量比为2/10时,复合材料的吸波性能最好,厚度为2.2mm时,掺La以与未掺La的W型铁氧体与磁性合金Fe85 Si1, A16 Cr8微粉的复合材料,吸波曲线的峰值点分别可达-40.6dB和-51.8dB；该复合吸波材料兼具铁氧体材料电阻率高、电磁匹配性好、高频电磁性能佳的优点以及磁性合金吸波材料磁导率高和磁损耗高的优点。更多还原

【Abstract】 W-type barium hexagonal ferrite presents relativly large saturation magnetization, strong magnetic crystalline anisotropy and good chemical stability,and are widely used in microwave devices and electromagnetic wave absorbers.Focus on the microwave electromagnetic characteristics of W-type hexagonal barium ferrite Ba1Zn2Fe16027,effects of compositions, technology parameters and doping ions on the microwave paraters,and microwave absorbing properties were studied. The W-type hexagonal barium ferrite doped with rare earth ions were especially researched on microstructures and electromagnetic characteristics. Based on microwave loss of the W-type hexagonal barium ferrite, the composites from W-type hexagonal barium ferrite and Fe-based alloy were evaluated electromagnetic properties and microwave absorbing abilitis.A modified sol-gel technology were adopted which enclosed two-step heating process in the calcining stage. After the preheating process, the phase formation temperature of the hexagonal ferrit can be effectively.Substitution of ion doping on microstructures and magnetic properties of the W-type hexagonal barium ferrite were investigated. Firstly, substitution of Zn2+by different amount of Co2+in the position B was explored and it showed that, when the amount of doping Co2+is 0.9, the absorption peak value is-33.6 dB. Furthermore, effects of the doping ions in position A and position B, for example, Ba2+in the position A was substituted by La3+at the amount of bit 0.2 and Zn2+in the position B was substituted by Co2+at the amount of bit 0.9, results show that the W-type hexagonal BaLaCoZn ferrite pesents the peak absorbing value of-39.6 dB.Based on the prepared W-type hexagonal barium ferrite, composties from the ferrite and the iron-based alloy were discussed. When the mass ratio is 2/10, the absorbing peak values of composite materials are-40.6 dB and-51.8 dB respectively for the Za3+doping composite and undoped La3+composite in the layer thickness of 2.2 mm.The absorbing composite materials exhihit high resistivity, good electromagnetic impedance matching and superior high-frequency electromagnetic properties as ferrite, and also large permeability and magnetic loss as the alloy.更多还原