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研究了La_(0.9)Ce_(0.1)Fe_(11.45)Si_(1.55)H_(1.8)合金及其粉末粘结样品的磁热性能,通过在吸氢后粉末化的合金中加入一定量的粘接剂,制备出块状的化合物,利用X射线衍射物相分析(XRD)和振动样品磁强计(VSM)测量了合金吸氢前后的相结构和磁性曲线。研究表明,粘结后的样品主相仍然为NaZn_(13)型立方结构,同时材料中存在少量的杂相α-Fe。氢原子进入晶格间隙导致合金的居里温度明显升高,但氢化物合金及其粉末粘结样品的最大等温磁熵变降低相比吸氢前更明显,一级相变特征减弱。粉末粘结样品的居里温度略微降低于氢化物合金。粘结化合物的最大等温磁熵变相对于氢化物合金也略微降低,但与二级相变金属Gd比仍保持较高的磁热性能。悬浮熔炼的La_(0.9)Ce_(0.1)Fe_(11.45)Si_(1.55)合金经1070℃退火处理144 h后样品居里温度190 K,最大磁熵变为11.82 J/(kg·K),经320℃和0.03 MPa压力吸氢6 h后,居里温度提高到335 K,最大磁熵变为6.7 J/(kg·K)。粘结氢化物在250 MPa压力下成型5 min后,获得样品的最大磁熵变为6.05 J/(kg·K),居里温度为331 K。
The magnetocaloric properties of the La_ (0.9) Ce_ (0.1) Fe_ (11.45) Si_ (1.55) H_ (1.8) alloy and its powder bonded samples were studied by adding a certain amount of adhesion The bulk compounds were prepared. The phase structure and magnetic curve before and after hydrogen absorption were measured by X-ray diffraction (XRD) and vibrating sample magnetometer (VSM). The results show that the main phase of the bonded sample is still NaZn_ (13) -type cubic structure with a small amount of heterogeneous α-Fe in the material. When the hydrogen atoms enter into the lattice space, the Curie temperature of the alloy increases obviously, but the maximum isothermal magnetic entropy change of the hydride alloy and its powder bonded sample is more obvious than that before hydrogen absorption, and the first-order phase transition characteristic is weakened. The Curie temperature of the powder-bonded samples slightly decreases in the hydride alloy. The maximum isothermal magnetic entropy change of the bonding compounds is also slightly lower than that of the hydride alloy, but the magnetocaloric property remains higher than that of the second-order phase transition metal Gd. After annealing at 1070 ℃ for 144 h, the Curie temperature of the La_ (0.9) Ce_ (0.1) Fe_ (11.45) Si_ (1.55) alloy after suspension melting was 190 K and the maximum magnetic entropy changed to 11.82 J / (kg · K) After hydrogen storage at 320 ℃ and pressure of 0.03 MPa for 6 h, the Curie temperature increased to 335 K and the maximum magnetic entropy changed to 6.7 J / (kg · K). The maximum magnetic entropy of the sample obtained after the bonded hydride was molded at 250 MPa for 5 min was 6.05 J / (kg · K), and the Curie temperature was 331 K.