Martensitic transformation in Fe-Ni nanoparticles prepared by a sol-gel process

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• 作者：Jie Zhang^a ; Mingjiang Jin^b ; Fei Xiao^b ; Cheng Li^a ; Xuejun Jin^a ; ^{jin@sjtu.edu.cn}
• 关键词：Martensitic transformation ; Nanoparticles ; Fe&ndash ; Ni ; Sol&ndash ; gel preparation ; MPMS ; Ms
• 刊名：Materials Letters
• 出版年：2012
• 期刊代码：59_0167577x
• 类别：ms
• 出版时间：1 August, 2012
• 卷：80
• 期：Complete
• 页码：152-154
• 文件大小：437 K

摘要

The Fe-29.5 wt.%Ni, Fe-33.0 wt.%Ni, Fe-35.9 wt.%Ni nanoparticles with narrow size distribution were prepared via a sol-gel process followed by a reduction treatment. The MT (martensitic transformation) of Fe-Ni nanoparticles was studied by Magnetic Property Measurement System (MPMS) and X-ray Diffraction (XRD). It was found that a considerable amount of low temperature martensite in Fe-29.5 wt.%Ni and a small amount of martensite in Fe-33.0 wt.%Ni nanoparticles were detected by XRD at room temperature, while martensite was not detected in the Fe-35.9 wt.%Ni nanoparticles, showing apparently compositional dependence of MT in Fe-Ni nanoparticles. Moreover, the Ms (defined as turning point of the increasing rate of magnetic susceptibility [1]) of Fe-33 wt.%Ni nanoparticles with an average particle size of 19.4 nm was tested as high as 246 K by both MPMS and XRD, which was nearly 100 K higher than the Ms of counterpart Fe-33 wt.%Ni bulk specimen. The possible reasons for high Ms of nanoparticles were discussed.