Cu添加对La0.7Ce0.3Fe11.54-xCuxMn0.16Si1.3合金及其氢化物磁性能的影响

Influence of Cu on the Magnetic Properties of La0.7Ce0.3Fe11.54-xCuxMn0.16Si1.3 Alloy and its Hydride

摘要:

La(Fe, Si)₁₃系合金是具有一级相变大磁热效应的磁制冷合金,被认为是极具应用前景的磁热效应材料之一。本文采用高频感应悬浮炉制备了添加不同Cu元素比例的La_0.7Ce_0.3Fe_11.54-xCu_xMn_0.16Si_1.3(x=0, 0.05, 0.1, 0.15)合金。并利用粉末XRD衍射仪,扫描电镜(SEM)对合金的相组成、微观组织结构进行了研究,采用多功能振动样品磁强计VersaLab对合金的磁性能进行了分析。添加Cu元素后,合金的居里温度提高,但氢化后添加Cu的合金居里温度反而偏低。随着Cu元素提高磁热性能下降,但La_0.7Ce_0.3Fe_11.44Cu_0.1Mn_0.16Si_1.3H_1.68合金的最大等温磁熵变仍高达8.5 J/kg.K(0 ~ 2 T),相对制冷能力RCP提高(118 J/kg),磁滞明显降低。

Abstract:

La(Fe, Si)₁₃ alloys exhibit first order magnetic transition showing large magnetocaloric effect, and is considered as a magnetocaloric effect material with the great applied prospect. La_0.7Ce_0.3Fe_11.54-xCu_xMn_0.16Si_1.3(x=0, 0.05, 0.1, 0.15)alloys with different proportion of Cu were prepared by high frequence induction melting furnace. With the aid of powder XRD and scanning electron microscope (SEM), the phase composition and microstructure were investigated. The magnetic properties were measured by using VersaLab. Curie temperature increases after partial substitution Cu for Fe, however an opposite result is obtained after hydrogenation. Although the magnetocaloric effects decrease with the increase of Cu content, the max magnetic entropy change of La_0.7Ce_0.3Fe_11.44Cu_0.1Mn_0.16Si_1.3H_1.68alloy is still as high as 8.5 J/kg.K(0 ~ 2 T), the relative cooling capacity improved (118 J/kg) and the hysteresis decrease evidently.