Formation of Co–Pt Intermetallic Compound Nanoparticles by Plasma-Induced Cathodic Discharge Electrolysis in a Chloride Melt
Formation of Co–Pt Intermetallic Compound Nanoparticles by Plasma-Induced Cathodic Discharge Electrolysis in a Chloride Melt
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DOI：
10.1149/1.3526623
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发表时间：
2011-02
影响因子：
3.9
通讯作者：
M. Tokushige;A. Matsuura;T. Nishikiori;Y. Ito
中科院分区：
文献类型：
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作者：
M. Tokushige;A. Matsuura;T. Nishikiori;Y. Ito
Co-Pt金属间化合物纳米颗粒通过在熔融LiCl-KCl电解质中在400-500°C和Iatm的Ar气氛下的等离子体诱导阴极放电电解形成。采用了两种不同的方法：电化学形成的Co纳米颗粒和Pt（II）之间的置换反应，和Co和Pt的共沉积。在这两种方法中，特别注意通过实验条件来控制Co-Pt颗粒的金属间化合物组成。结果表明，电解结束后，在熔体中形成的纳米颗粒的停留时间对颗粒的组成和磁性都有影响。在置换反应中，富Pt相（CoPt 3）主要在停留初期形成，随着停留时间的延长，富Pt相转变为富Co相（Co 3 Pt）。所得颗粒的电导率在400°C下为54.1 kA m-1，在500°C下为64.9 kA m-1。在共沉积的情况下，Co-Pt纳米颗粒的组成也随着终止电解后的长停留时间从富Pt相变为富Co相。所得颗粒的介电常数（375 kAm-l）比通过置换反应获得的颗粒的介电常数高。
Co-Pt intermetallic compound nanoparticles were formed by plasma-induced cathodic discharge electrolysis in molten LiCl-KCl electrolytes at 400-500°C under 1 atm of Ar atmosphere. Two different approaches were adopted: the displacement reaction between an electrochemically formed Co nanoparticle and Pt(II), and the codeposition of Co and Pt. In both approaches, special attention was paid to controlling the intermetallic composition of the Co-Pt particle by the experimental condition. It was found that both the composition of the particle and its magnetic property were affected by the residence time of the nanoparticle formed in the melt after terminating the electrolysis. In the displacement reaction, the Pt-rich phase (CoPt 3 ) was predominantly formed at an early stage of the residence, which changed to a Co-rich phase (Co 3 Pt) when the residence time became longer. The coercivity of the obtained particle was 54.1 kA m -1 at 400°C and was 64.9 kA m -1 at 500°C. In the case of the codeposition, the composition of the Co-Pt nanoparticle also changed from the Pt-rich phase to the Co-rich phase with the long residence time after terminating the electrolysis. The coercivity of the obtained particle showed a higher value (375 kA m -1 ) than that of the particle obtained by the displacement reaction.