放电等离子烧结Gd/Gd_5Si_2Ge_2复合材料磁热效应研究

Magneto-caloric effect of Gd_5Si_2Ge_2/Gd composite materials prepared by spark plasma sintering

以高纯钆和Gd5Si2Ge2合金为原料,采用放电等离子烧结技术制备了两组元Gdx(Gd5Si2Ge2)1-x(x=0,0.33,0.5,0.7,1)层状复合磁制冷材料.通过自制的磁热效应测量仪器直接测量了复合材料在外加磁场1.5 T下的磁热效应(ΔTad).随着复合比例的变化,材料的最大绝热温变(ΔTad)从x=0.3时的1.6 K增加到x=0.7时的2.0 K,而最大绝热温变峰的位置从286K变到了293 K.同时,与单组元的Gd5Si2Ge2合金相比,随着钆的含量增加时,复合材料的最大绝热温变峰变宽.当x=0.7时,层状复合磁制冷材料在外加磁场1.5 T下的最大绝热温变(ΔT)在260-310K范围里从1.1 K变到2.0 K,这种材料非常适合作为室温磁制冷材料.

The binary composite Gdx （ GdsSi2Ge2 ）1 -x [ （ x = 0,0. 3, 0.5, 0.7,1 ） ] with layer structures was synthesized by spark plasma sintering （SPS） technique using high purity Gadolinium （Gd） and Gd5Si2Ge2 alloys as materials. The magneto - caloric effect of the composites was studied by directly measuring the adiabatic temperature change （ △Tad ） with a magnetic field change of 1.5 T using a homemade magneto - caloric effect measuring apparatus. With the increasing of x from 0. 3 to 0. 7, the △Tad peak position shifted from 286 to 293 K and the peak values slowly increased from 1.6 K to 2.0 K with a magnetic field change of 1.5 T. Meanwhile, the △Tad peak of the composite became broad as the Gd content was increased compared with that of the component of GdsSi2G% alloy. For x =0.7,the △Tad of the composite changed from 1.1 K to 2. 0 K in the range of 260 K to 310K with a magnetic field change of 1.5 T.