LaFe11．9-xCoxSi1．1B0．2(x=0．7，0．8，0．9)合金的磁热效应

MAGNETOCALORIC EFFECT OF LaFe_(11.9-x)Co_xSi_(1.1)B_(0.2) (x=0.7,0.8,0.9) ALLOYS

使用电弧熔炼法制备了LaFe_(11.9-x)Co_xSi_(1.1)B_(0.2)(x=0.7,0.8,0.9)系列合金.XRD分析表明该系列合金除微量的α-Fe相外,均由NaZn_(13)型立方结构单相组成.晶格常数随着Co含量的增加而增大,分别为1.1487,1.1496,1.1498 nm;磁性测量表明该系列合金的Curie温度在室温附近,并且也随着Co含量的增加而分别增加到270,290,300 K.在外场变化ΔB=1.5 T时,该系列合金的最大磁熵变均为金属Gd的2倍左右,相对制冷能力与金属Gd基本相同.

The LaFe11.9-xCoxSi1.1B0.2（x=0.7, 0.8, 0.9） alloys were prepared by arc melting. XRD analysis showed that the LaFe11.9-xCoxSi1.1B0.2 alloys consist of the NaZn13-type cubic phase and minor amount of α-Fe phase. It is found that the cell constants and the cell volumes slightly increased with increasing x, the constants increased from 1.1487 to 1.1496 and 1.1498 nm and the volumes from 1.5159 to 1.5194 and 1.5199 nm^3 for x=0.7, 0.8 and 0.9,respectively. The magnetic measurement showed that the Curie temperature of the alloys slightly increases with increasing Co and nears the room temperature, 270, 290 and 300 K for x=0.7, 0.8 and 0.9, respectively. The maximum values of the magnetic entropy change are 7.47, 5.93 and 5.90 J/（kg·K） for x=0.7, 0.8 and 0.9, respectively, as field change from 0 to 1.5 T, which exceeded by one time of that of industrial Gd at the corresponding applied field. The relative cooling power （RCP） based on the magnetic entropy change is as large as that of industrial Gd at the corresponding applied field.