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首页> 外文期刊>Materials Letters >Crystallisation of hexagonal M ferrites from a stoichiometric sol―gel precursor, without formation of the α-BaFe_2O_4 intermediate phase
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Crystallisation of hexagonal M ferrites from a stoichiometric sol―gel precursor, without formation of the α-BaFe_2O_4 intermediate phase

机译:从化学计量的溶胶-凝胶前体中结晶出六角型M铁氧体,而没有形成α-BaFe_2O_4中间相

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摘要

Single phase BaM (BaFe_(12)O_(19)) and SrM (SrFe_(12)O_(19)) ferrites were made from stoichiometric aqueous sol-gel precursors, and two different types of precursor sol were used, containing either halide or nitrate anions. It was found that halides were retained in the ferrite precursors to over 900℃ and delayed the formation of the M ferrite phase. This resulted in the formation of M ferrite at a temperature up to 200℃ higher for the halide-derived samples, compared to the nitrate-derived samples. Single phase halide-derived BaM and SrM were formed at 1000 and 850℃, respectively, while the nitrate-derived precursors formed single phase BaM and SrM at 750 and 700℃, respectively. No α-BaFe_2O_4, γ-Fe_2O_3 or any other ferrite intermediate was observed in the BaM precursor powder, the M ferrite forming directly from α-Fe_2O_3 and barium salts. This indicated that the formation of a-BaFe_2O_4 or γ-Fe_2O_3 is not necessary for the formation of BaM ferrite.
机译:单相BaM(BaFe_(12)O_(19))和SrM(SrFe_(12)O_(19))铁氧体由化学计量的水溶胶-凝胶前体制成,并使用两种不同类型的前体溶胶,其中既含卤化物也含卤化物硝酸根阴离子。发现卤化物保留在铁氧体前体中至900℃以上,并延迟了M铁氧体相的形成。与源自硝酸盐的样品相比,这导致卤化物衍生的样品在高达200℃的温度下形成M铁氧体。卤化物衍生的单相BaM和SrM分别在1000和850℃下形成,而硝酸盐衍生的前体分别在750和700℃形成单相BaM和SrM。在BaM前体粉末中未观察到α-BaFe_2O_4,γ-Fe_2O_3或任何其他铁氧体中间体,M铁氧体直接由α-Fe_2O_3和钡盐形成。这表明,对于BaM铁氧体的形成,不需要形成a-BaFe_2O_4或γ-Fe_2O_3。

著录项

  • 来源
    《Materials Letters》 |2002年第3期|p.537-542|共6页
  • 作者

    R.C. Pullar; A.K. Bhattacharya;

  • 作者单位

    Centre for Physical Electronics and Materials, School of Electrical, Electronic and Information Engineering, South Bank University, 103 Borough Road, London SE1 0AA, UK;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 工程材料学;
  • 关键词

    magnetic materials; sol-gel preparation; ceramics;

    机译:磁性材料溶胶-凝胶制备;陶瓷;

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