摘要
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 effects of La（0.9）Ce（0.1）Fe（11.45）Si（1.55）H（1.8） alloy and its powder bonded sample have been investigated.By adding a certain amount of epoxy resin in the powder alloy of hydride,the block samples have been prepared,and their crystal structure and magnetocaloric properties are measured by XRD and VSM,respectively.Studies show that the major phase of bonded La（0.9）Ce（0.1）Fe（11.45）Si（1.55）H（1.8） is still Na Zn13- type cubic structure,there is also a small amount of α- Fe as impurity phase.The Curie temperature Tcdecreases slightly corresponding to the hydride alloy.Compared with parent alloy,the maximum magnetic entropy change of La（0.9）Ce（0.1）Fe（11.45）Si（1.55）H（1.8） and its bonded samples reduces because of reduction of the first- order transition by the interstitial H atom.The La（0.9）Ce（0.1）Fe（11.45）Si（1.55） alloy produced by suspension smelting possesses a maximum magnetic entropy change of 11.82 J / kg·K and Curie temperature of 190 K after annealed at 1070℃ for 144 h.The La（0.9）Ce（0.1）Fe（11.45）Si（1.55）H（1.8） hydride has a maximum magnetic entropy change of 6.7 J / kg·K and Curie temperature of 335 K by hydrogenated at 320℃ for 6h under hydrogen pressure of 0.03 MPa.The bonded hydride shows a maximum magnetic entropy change of 6.05 J / kg·K and its Curie temperature is 331 K.
出处
《稀土》
EI
CAS
CSCD
北大核心
2017年第1期61-65,共5页
Chinese Rare Earths
基金
国家自然科学基金项目(51261001)
国际合作项目(2011DFA53230)
关键词
粉末粘结
居里温度
磁熵变
bonded powder
Curie temperature
magnetic entropy change
