自蔓延高温合成La-Zn掺杂锶铁氧体改性研究

Sr-hexaferrites with La-Zn Substitution Prepared by Self-propagating High-temperature Synthesis

采用高温自蔓延（SHS）方法制备了化学组成为Sr1-xLaxFe12-xZnxO19（x=0～0．4）的La-Zn联合掺杂的锶铁氧体，并研究了晶体结构与离子掺杂量对铁氧体磁性能的影响。根据相关的热力学数据，分析了合成过程中产生不同氧化物杂质的热力学机制，结果显示，通过合适控制反应体系中的Fe粉含量，可以合成单一的M型铁氧体相。SEM表明SHS方法制备的样品比传统方法制备的样品结晶更完整，粉体颗粒呈明显的六角平板状，颗粒尺寸基本分布在0．5～1．2μm之间。La^3＋，Zn^2＋的加入能够明显地提高试样的综合磁性能，相比于未掺杂的试样，在未取向情况下其剩磁提高了14．4％，Hcb提高了15．3％，（BH）m提高了30．7％，并且与传统制备方法相比，采用SHS方法获得的样品的内禀矫顽力Hcj提高尤为明显，最高可达322kA／m。

The La-Zn substituted SrM-type ferrites with the composition of Sr1-x LaxFe12-x Znx O19 （x= 0-0.4） were prepared by self-propagating high-temperature synthesis （SHS）. The thermodynamic mechanism forming the different impurities of oxides containing Fe was analyzed according to the corresponding thermodynamic data. The results show that the single SrM-type ferrite can be achieved by controlling the Fe contents in the reagents. The substitution of La^3＋ and Zn^2＋ obviously increases the magnetic properties of the as-prepared samples. The maximum improvements of Br, Hcb and （BH）m are 14.4%, 15.3% and 30.7% respectively compared with that of the samples without La-Zn substitution. In comparison with the traditional firing method, the SHS method benefits forming the better particle features observed by SEM and achieving the higher Hcj.