Synthesis of ferrite and nickel ferrite nanoparticles using radio-frequency thermal plasma torch
Synthesis of ferrite and nickel ferrite nanoparticles using radio-frequency thermal plasma torch
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DOI：
10.1063/1.1452705
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发表时间：
2002-05
影响因子：
3.2
通讯作者：
S. Son;M. Taheri;E. Carpenter;V. Harris;M. McHenry
中科院分区：
文献类型：
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作者：
S. Son;M. Taheri;E. Carpenter;V. Harris;M. McHenry
采用50 kW-3 MHz射频热等离子体炬合成了纳米晶（NC）铁氧体粉末。使用Ni和Fe的混合粉末（Ni：Fe=1：2）、具有附加Fe粉末的NiFe坡莫合金粉末（Ni：Fe=1：2）和NiFe坡莫合金粉末（Ni：Fe=1：1）作为合成前体。进入反应器室的空气流是用于氧化物形成的氧源。XRD图谱清楚地表明，前驱体粉末转化为平均粒径为20-30 nm的NC铁氧体颗粒。SEM和TEM研究表明，NC铁氧体颗粒具有明确的多边形生长形式，其中一些表现出（111）面，许多具有截顶八面体和截顶立方体形状。观察到铁氧体颗粒中的Ni含量在从混合的Ni和Fe到混合的坡莫合金和铁以及最后到仅坡莫合金起始前体的过程中增加。采用NiFe坡莫合金前驱体，等离子炬合成的铁氧体材料，具有40%~ 4.0%的热稳定性。
Nanocrystalline (NC) ferrite powders have been synthesized using a 50 kW–3 MHz rf thermal plasma torch for high-frequency soft magnet applications. A mixed powder of Ni and Fe (Ni:Fe=1:2), a NiFe permalloy powder with additional Fe powder (Ni:Fe=1:2), and a NiFe permalloy powder (Ni:Fe=1:1) were used as precursors for synthesis. Airflow into the reactor chamber was the source of oxygen for oxide formation. XRD patterns clearly show that the precursor powders were transformed into NC ferrite particles with an average particle size of 20–30 nm. SEM and TEM studies indicated that NC ferrite particles had well-defined polygonal growth forms with some exhibiting (111) faceting and many with truncated octahedral and truncated cubic shapes. The Ni content in the ferrite particles was observed to increase in going from mixed Ni and Fe to mixed permalloy and iron and finally to only permalloy starting precursor. The plasma-torch synthesized ferrite materials using exclusively the NiFe permalloy precursor had 40%–4...