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采用XRD、SEM和VSM等方法研究凝固速度和过量Fe对LaFe_(11.6x)Si_(1.4)(x=1.1,1.2)试样相形成和磁热性能的影响。XRD研究结果表明,以10 m/s速度甩带制备的铸态LaFe_(11.6x)Si_(1.4)试样中LaFeSi相的含量低于采用电弧熔炼的相同配比铸态LaFe_(11.6x)Si_(1.4)纽扣试样中LaFeSi相的含量,且在对应热处理后试样中,甩带试样中的La(Fe,Si)_(13)相(1:13相)的含量也更低。SEM结果表明,虽然甩带能使热处理后试样中α-Fe相晶粒组织细化,但并未达到纳米级,因此,未观察到1:13相和α-Fe相中磁性原子的磁耦合现象。磁热性能研究表明,经过相同热处理后甩带LaFe_(11.6x)Si_(1.4)试样在0～2 T磁场中的最大磁熵变和相对制冷能力也低于同成分LaFe_(11.6x)Si_(1.4)纽扣试样的最大磁熵和相对制冷能力。
The effects of solidification rate and excess Fe on the phase and magnetocaloric properties of LaFe_ (11.6x) Si_ (1.4) (x = 1.1 and 1.2) samples were investigated by XRD, SEM and VSM methods. The XRD results show that the content of LaFeSi in the as-cast LaFe 11.6x Si 1.4 sample prepared at the rejection of 10 m / s is lower than that of LaFe 11.6x Si 11.4x (1.4) The content of LaFeSi phase in the button specimen and the content of La (Fe, Si) _ (13) phase (1:13 phase) in the rejection specimen in the sample after heat treatment are also lower. SEM results show that although the rejection zone can refine the α-Fe phase grain structure in the sample after heat treatment, it does not reach the nanometer scale. Therefore, the magnetism of the magnetic atoms in the 1:13 phase and α-Fe phase is not observed Coupling phenomenon. The results of magnetocaloric properties show that the maximum magnetic entropy change and relative cooling capacity of LaFe_ (11.6x) Si_ (1.4) samples after 0 ~ 2 T magnetic field are lower than that of LaFe_ (11.6x) Si_ (1.4) The maximum magnetic entropy and relative cooling capacity of the button specimen.