自蔓延高温合成La-Zn掺杂锶铁氧体改性研究

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0.5～1.2 μm之间.La3 ,Zn2 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.

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

The La-Zn substituted SrM-type ferrites with the composition of Sr1-xLaxFe12-xZnxO19(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 La3+ and Zn2+ 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.