LaFe_(11.9)Co_xSi_(1.1)C_(0.15)(x=0.70,0.75,0.80)合金的磁热性能

The Magnetocaloric Property of LaFe_(11.9)Co_xSi_(1.1)C_(0.15)(x = 0.70,0.75,0.80) Alloy

利用高频悬浮炉熔炼LaFe_(11.9)Co_xSi_(1.1)C_(0.15)(x=0.70,0.75,0.80)合金锭,高纯氩气环境下,在1363 K温度下退火144 h,随炉冷却到室温。对得到的样品进行XRD相图分析,主相均为Na Zn13型立方结构,且晶格常数随着Co含量的增多有所增大。LaFe_(11.9-x)Co_xSi_(1.1)C_(0.15)(x=0.70,0.75,0.80)合金的居里温度分别为291 K、296 K、303K,最大磁熵变为6.0 J/(kg·K)、5.6 J/(kg·K)、4.5J/(kg·K),即随着Co含量的增加,材料的居里温度逐渐升高,最大磁熵变值逐渐降低。并且,随着Co含量增加材料的抗压强度也逐渐增大,在x=0.80时最大抗压强度为749.6 MPa,通过计算LaFe_(11.15)Co_(0.75)Si_(1.1)C_(0.15)的RCP(S)值约为123.2 J/K,与Gd的相差不大,能够满足室温磁制冷机实用。

LaFe11.9 Cox Si1.1C0.15 （x = 0.70,0.75, 0.80 ） alloy was prepared by high frequency furnace with annealing at 1363K for 144 h at the atmosphere of Ar and then furnace cooling to room temperature. Phase diagram of the sample is ana- lyzed by XRD, which indicated that the main phase of the material is NaZn13 type cubic structure, and the lattice constant in- creased with the increase of Co content. The Curie temperature of the LaFe11. 9-xCox-Si1.1 C0. 15 （ x = 0. 70,0. 75,0. 80） were 291 K,296 K,303 K and the max magnetic entropy were 6.0 J/（ kg · K） ,5.6 J/（ kg · K） ,4.5J/（ kg · K）, respectively. The re- suits show with the increase of Co content, the Curie temperature of the material is rises and the maximum magnetic entropy change decreases. Meanwhile, the compressive strength of the material also increases and the maximum compressive strength 749.6MPa was obtained when x = 0.80. The calculated RCP （S） value of LaFe jl. 15 Coo 75 Sit. l Co. 15 is about 123.2 J/K, close to that of Gd, which can meet the practical requirements of room temperature magnetic refrigerators.