哈斯勒合金Ni-Mn-Sn的磁热效应

采用真空电弧熔炼法和高温淬火法制备了四元哈斯勒合金Ni50-xCuxMn36Sn14(x=0,2,4,6)的化合物。用X射线衍射仪和振动样品磁强计研究了合金的物相与磁热效应。结果表明,部分Cu元素对Ni的替代,并没有改变三元哈斯勒合金Ni-Mn-Sn原有的晶体结构,只是晶格常数开始有减小的趋势,晶胞的体积没有发生太大的变化。M-T曲线的结果表明,该系列哈斯勒合金样品在奥氏体相的铁磁交换作用增强,导致居里温度升高,而结构相变温度降低。此外,通过麦克斯韦方程计算了该系列合金的磁熵变(-ΔSm),在磁场变化为1.5 T的情况下,获得了Ni46Cu4Mn36Sn14合金在330 K附近的最大磁熵变(-ΔSmmax)约为2.0 J·(kg·K)-1。

Magnetocaloric Effect of Heusler Alloy Ni-Mn-Sn

The Ni50-xCuxMn36Sn14(x=0,2,4,6) compounds were prepared by means of arc melting and high-temperature quenching.The structure and the phase transition characteristics of the compounds were investigated by using X-ray diffraction and Vibrating sample magnetometer.X-ray diffraction showed that substitution of Cu for Ni did not change the crystal structure of the ternary Heusler alloy Ni-Mn-Sn,but the lattice constants decreased,and the unit cell volume almost unchanged.Magnetic measurements showed that ferromagnetic exchange interaction enhanced in the austenite phase of the samples,leading to the increase of Curie temperature,while the structural phase transition temperature reduced.The maximal magnetic entropy change ΔSM of the Ni46Cu4Mn36Sn14 alloys was about 2.0 J ·(kg · K)-1,near the 330 K in a field change of 1.5 T.