La0.9Ce0.1Fe11.44Si1.56H1.56粉末粘结块体的制备及磁热效应  

Preparation and Magnetocaloric Effect of La0.9Ce0.1Fe11.44Si1.56H1.56 Power Bonded Block

作　　者：慕利娟[1] 黄焦宏 刘翠兰[2,3] 赵增祺 Mu Lijuan;Huang Jiaohong;Liu Cuilan;Zhao Zengqi(School of Science, Inner Mongolia University of Science and Technology, Baotou 014010, China;State Key Laboratory of Baiyun Obo Rare Earth Resource Research and Comprehensive Utilization, Baotou 014030, China;Baotou Research Institute of Rare Earths, Baotou 014030, China)

机构地区：[1]内蒙古科技大学理学院,内蒙古包头014010 [2]白云鄂博稀土资源研究与综合利用国家重点实验室,内蒙古包头014030 [3]包头稀土研究院,内蒙古包头014030

出　　处：《稀有金属》2018年第6期614-620,共7页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(51261001)资助

摘　　要：通过高频熔炼、高温短时退火及吸氢的方法获得了饱和La0.9Ce0.1Fe11.44Si1.56H1.56含氢合金,对吸氢后的样品进行研磨,采取粉末粘结及压制成型的方法制备出粘结La0.9Ce0.1Fe11.44Si1.56H1.56块状含氢合金。利用扫描电子显微镜（SEM）、万能试验机、振动样品磁强计（VSM）及磁热效应（MCE）直接测量仪对样品的微观结构、力学性能和磁热效应进行了研究。吸氢之后含氢合金样品的Curie温度达到室温附近,但合金经吸氢后沿其晶界碎裂,力学性能下降,不适合磁制冷机的运行环境。在700 MPa的压力下,采用环氧树脂粘结的方法把脆化的含氢合金压制成圆柱状块体。粉末粘结后的含氢合金块体为多孔结构,在不同的颗粒之间存在有大量的孔隙和边界,研磨后粒度〈0.20 mm的块状含氢合金的最大抗压强度达到205 MPa。在1.5 T的低磁场下,具有比二级相变材料Gd金属和La-Fe-Co-Si-B合金更优异的磁热性能,绝热温变和等温磁熵变的最大值分别达到2.7 K和7.5 J·（kg·K）-1,可以作为室温磁工质应用于磁制冷机中。The saturated La0.9Ce0.1Fe11.44Si1.56H1.56 hydride was prepared by high frequency induction furnace,the high-temperature short-time annealing,and then hydrogen absorption. The bonded La0.9Ce0.1Fe11.44Si1.56H1.56 block was prepared by grinding,and then by powder bonding and compacting process. The microstructures,mechanical properties and magnetocaloric effects（MCE） were investigated by scanning electron microscope（SEM）,universal testing machine,vibrating sample magnetometer（VSM）,and the MCE direct measurement automatic device. After hydrogen absorption,the Curie temperature of hydride increased up to the vicinity of room temperature,but hydrogen crack occurred along with the grain boundary of the alloy during hydrogen absorption process,which reduced the mechanical properties. The poor mechanical properties could not meet the application requirements used in magnetic refrigerator.So,the brittle hydride were mixed with epoxy resin and then pressed into cylindrical block under a pressure of 700 MPa. The bonded hydride block had porous structure and there had large number of pores and boundaries between different particles. The compressive strength reached 205 MPa for the bonded La0.9Ce0.1Fe11.44Si1.56H1.56 when the grain size was smaller than 0. 2 mm. For a low magnetic field change of 1. 5 T,the magnetocaloric effects of the bonded hydride were larger than those of Gd and La-Fe-Co-Si-B alloys. The values of maximum adiabatic temperature change and magnetic entropy change for bonded hydride were about 2. 7 K and 7. 5 J·kg^-1·K-1,respectively. The bonded hydride could be used as the room temperature magnetic refrigerant for the practical application in magnetic refrigerators.

关 键 词：La0.9Ce0.1Fe11.44Si1.56H1.56 粉末粘结 抗压强度 磁热效应 

分 类 号：TM271[一般工业技术—材料科学与工程] TB64[电气工程—电工理论与新技术]