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将LaSi母合金和元素粉末混合,利用球磨工艺制备了La(Fe_(1-x)Co_x)_(11.2)Si_(1.8)(x=0,0.02,0.04,0.06)样品。在1423 K的温度下烧结30min,然后放入水中快速冷却,就可以获得几乎为NaZn_(13)型结构的单相化合物。磁性质的研究表明,样品的居里温度随着Co含量从x=0到x=0.06而提高,但是磁熵变减小。在0~1.5 T的外加磁场下,LaFe_(11.2)Si_(1.8)合金在其居里温度附近的最大磁熵变达到的6.5 J/kg,而x=0.06的样品的最大磁熵变约为2.1 J/(kg·K)。另外,球磨制备的样品还呈现了二级磁相变的特点,这对于磁热效应的应用非常有意义。
The LaSi master alloy and the elemental powder were mixed, and La (Fe 1-x) Co x) _ (11.2) Si 1.8 (x = 0,0.02,0.04,0.06) samples were prepared by ball milling. Sintering at a temperature of 1423 K for 30 min followed by rapid cooling in water gives a nearly monochromatic compound of the NaZn 13 type structure. Magnetic properties show that the Curie temperature increases with the Co content from x = 0 to x = 0.06, but the magnetic entropy decreases. Under the applied magnetic field of 0 ~ 1.5 T, the maximum magnetic entropy change of LaFe_ (11.2) Si_ (1.8) alloy reaches 6.5 J / kg near its Curie temperature, while the maximum magnetic entropy change of the sample with x = 0.06 is 2.1 J / (kg · K). In addition, the samples prepared by ball milling also show the characteristics of the second-order magnetic phase transformation, which is very significant for the application of magnetocaloric effect.