Mn1.2Fe0.8P0.74Ge0.26化合物的微观形貌及性能研究

Mn_1.2Fe_0.8P_0.74Ge_0.26化合物的微观形貌及性能研究

孟庆普，刘丹敏^*，张隐奇，肖卫强，王少博，张振路

（北京工业大学固体微结构与性能研究所，北京100124）

摘 要:MnFePGe系列化合物是一种新型的室温磁制冷材料，它绿色环保，且主要原材料锰铁磷价格低廉，因而得到了广泛的关注。本文采用机械合金化和放电等离子烧结技术制备了Mn_1.2Fe_0.8P_0.74Ge_0.26化合物，并通过SEM、X-射线能谱仪（EDS）和DSC等手段对其微观形貌、杂相分布以及磁热性能进行了研究。结果表明：该化合物存在组成元素的不均匀分布，并且在晶界处析出Fe₃Mn₄Ge₆和MnO杂相。通过对Mn_1.2Fe_0.8P_0.74Ge_0.26化合物进行均匀化退火处理明显改善了其晶界偏析，磁热性能得到显著提高。

关键词: 磁制冷；MnFePGe；杂相；均匀化退火

中图分类号：TM271；TG115.21⁺5.3   文献标识码：A   doi:10.3969/j.1000-6281.2015-04.006

Research on the microstructures and magnetocaloric properties of Mn_1.2Fe_0.8P_0.74Ge_0.26  compounds

MENG Qing-pu, LIU Dan-min^*, ZHANG Yin-qi, XIAO Wei-qiang, WANG Shao-bo, ZHANG Zhen-lu

(Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology，Beijing 100124，China)

Abstract: MnFePGe compounds is a new kind of magnetic refrigeration material at room temperature and environmental friendly. Furthermore, the main raw materials Mn, Fe and P have the merit of low prices. It has been widely concerned. In this paper, Mn_1.2Fe_0.8P_0.74Ge_0.26 compounds were prepared by mechanical milling and subsequent spark plasma sintering (SPS) technique. The microstructures, distribution of impurity phases and magnetocaloric properties were investigated by SEM, EDS and DSC. The results show that there exists compositional inhomogeneity in Mn_1.2Fe_0.8P_0.74Ge_0.26 compounds. The impurity phases are Fe₃Mn₄Ge₆ and MnO which distribute at grain boundaries. Homogenizing annealing can reduce the segregation at grain boundaries and significantly improve the magnetocaloric properties of the Mn_1.2Fe_0.8P_0.74Ge_0.26 compounds.

Keywords: magnetic refrigeration；MnFePGe；impurity phase；homogenizing annealing 

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