NaZn13型混合稀土-Fe-Si基合金的吸氢行为及相关磁性能研究

吸氢后的R(Fe,Si)13合金（R为混合稀土）因其在室温附近具有巨磁热效应而备受关注，研究R(Fe,Si)13合金的吸氢行为以及混合稀土对合金的磁性和磁热效应的影响规律对于实现室温磁制冷技术具有重要的科学指导意义。本项目以贮氢合金的吸氢反应动力学为基础，理论与实验相结合，系统地研究外部条件（包括热处理温度和时间、氢气压力等）和内在因素（包括混合稀土含量、过渡族元素替代、晶粒尺寸等）对合金吸氢速率和吸氢量的影响规律，进而揭示R(Fe,Si)13合金的吸氢动力学机制；采用磁化强度测量、比热测量和直接测量等多种方法，研究R(Fe,Si)13合金及其氢化物的磁性能、磁热效应和磁制冷能力，阐明混合稀土和氢对合金性能的联合作用规律。本项目的实施将为开发实用型室温磁制冷工质提供重要的科学依据，同时也为我国稀土资源的高效利用提供新途径。

Hydrogenated R(Fe,Si)13 alloys (R stands for mischmetal) have been paied much attention due to the giant magnetocaloric effect near room temperature. The behavior of hydrogen absorption and the influences of mischmetal on magnetic properties and magnetocaloric effect in the R(Fe,Si)13 alloys are greatly important for the achievement of room-temperature magnetic refrigeration. In the present project, on the basis of the hydrogen absorption kinetics in hydrogen storage alloys, the effects of external conditions (such as annealing temperature, heating time and hydrogen pressure) and intrinsic factors (such as content of mischmetal, substitution of transition metal, crystalline size) on the rate and quantity of the hydrogenating reaction in the alloys will be investigated experimentally and theoretically, from which, the mechanism of the hydrogenating reaction will be revealed. The combined interactions of the mischmetal and hydrogen on the magnetic properties, magnetocaloric effect and magnetic refrigeration capacity are studied by means of magnetization, heat capacity and direct measurements in the R(Fe,Si)13 alloys and their hydrides. The implementation of this project will offer scientific guidance for developing applicable magnetic refrigerants in room temperature range, and provide simultaneously a new way for the efficient utilization of the rare-earth resource in China.