采用X射线衍射技术、直接磁热效应测量仪和VSM振动样品磁强计研究电弧熔铸和400 ℃,1 h热处理后低纯 Gd_(0.95)Nb_(0.05)合金的磁热效应.结果表明:适量Nb的加入不改变商业Gd的居里温度,但明显提高了商业Gd的磁热效应,最大绝热温变由3.1 K增加到3.5 K,1.5 T磁场下最大磁熵变为3.99 J/(kg·K);Gd_(0.95)Nb_(0.05)合金经过400 ℃,1 h热处理后,居里温度提高了2 K,最大绝热温变和最大磁熵变有不同程度的增加.与高纯Gd相比,商业原料制备的Gd_(0.95)Nb_(0.05)合金成本低廉,是一种非常实用的磁制冷工质材料.
Magnetocaloric effect of low-purity Gd_(0.95)Nb_(0.05) alloys after arc-casting and 400 oC, 1 h heat treatment was studied by X-ray diffraction technique, direct magnetocaloric effect measuring instrument and vibrating sample magnetometer (VSM). The results show that proper amount of Nb addition doesn't change the Curie temperature of Gd but obviously improves its magnetocaloric effect. The maximum adiabatic temperature change of Gd_(0.95)Nb_(0.05) alloys increases to 3.5 K from 3.1 K in 1.2 T magnetic field, higher than that of commercial low-purity Gd. Meanwhile the maximum magnetic entropy of Gd_(0.95)Nb_(0.05) alloys reaches to 3.99 J/(kg·K) in 1.5 T magnetic field. After 400 oC, 1 h heat treatment, Curie temperature of Gd_(0.95)Nb_(0.05) alloys increases by 2 K, the maximum adiabatic temperature change increases to 3.6 K in 1.2 T magnetic field, and the maximum magnetic entropy also increases to 4.09 J/(kg·K) in 1.5 T magnetic field. Gd_(0.95)Nb_(0.05) alloys are a potential candidate of magnetic cooling materials with relatively low cost in commercial field.
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