Crystallization mechanism analysis of noncrystalline Ni-P nanoparticles through XRD, HRTEM and XAFS
Crystallization mechanism analysis of noncrystalline Ni-P nanoparticles through XRD, HRTEM and XAFS
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通过 XRD、HRTEM 和 XAFS 分析非晶 Ni-P 纳米颗粒的结晶机理
DOI：
10.1039/c4ce01130a
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发表时间：
2014-01-01
期刊：
影响因子：
3.1
通讯作者：
Wu, Zhonghua
中科院分区：
文献类型：
--
作者：
Tan, Yuanyuan;Sun, Dongbai;Wu, Zhonghua
通过 XRD、HRTEM 和 Ni K 边和 P K 边的 X 射线吸收精细结构 (XAFS) 谱研究了液相脉冲放电法制备的非晶 Ni-P 纳米粒子的结晶行为。发现 Ni3P 和 Ni 晶相之间存在竞争生长。颗粒内的主要相是结晶Ni3P和Ni，而亚稳相Ni-5(P, Ni)(2)以颗粒外的包覆壳形式存在。 P K 边 XANES 光谱中特征 D 的出现可以作为长程有序 Ni3P 形成的特征。 Ni3P 晶体理论值的拟合 P-Ni 键长的标准偏差 (Delta R/R) 可用于定义结晶过程。尽管在 250 摄氏度下 XRD 观察到纳米颗粒为非晶态，但它们的磁性可归因于 FCC-Ni 簇的形成。提出了一种结晶机制来描述所制备的非晶态 Ni-P 纳米粒子的结晶过程。
The crystallization behavior of noncrystalline Ni-P nanoparticles prepared by a liquid-phase pulsed-discharge method was studied through XRD, HRTEM, and X-ray absorption fine structure (XAFS) spectra from both Ni K-edge and P K-edge. A competitive growth between Ni3P and Ni crystalline phases was found. The main phases within the particles are crystalline Ni3P and Ni, while the metastable phase Ni-5(P, Ni)(2) is presented as a coated shell outside the particles. The appearance of feature D in the P K-edge XANES spectrum could be used as a characteristic for the formation of long-range ordered Ni3P. The standard deviation (Delta R/R) of the fitting P-Ni bond length from the theoretical value of a Ni3P crystal could be used to define the crystallization process. Although the nanoparticles were observed as XRD amorphous at 250 degrees C, their magnetic properties can be attributed to the formation of FCC-Ni clusters. A crystallization mechanism has been proposed to describe the crystallization process of the as-prepared noncrystalline Ni-P nanoparticles.