降低一级相变La(Fe,Si)13基片状块体材料的热滞和磁滞，改善其热传导能力和机械性能，是其实用化的核心科学问题。从La(Fe, Si)13铸态粉和快淬甩带粉出发，采用高氢气压合成工艺烧结制备高致密、颗粒均匀的片状La(Fe,Si)13基氢化物材料。系统地研究不同的高氢压、烧结时间、温度对片状La(Fe,Si)13氢化物块体的晶体结构、相组成、材料致密性、氢原子含量及占位、热稳定性、磁熵变及绝热温变的影响规律。分析烧结片状块体的微观孔洞及磁畴等微结构与滞后损耗、热导及脆性的对应规律及影响机制。同时研究元素掺杂，特别是原矿混合稀土掺杂在高氢压下对材料滞后损耗、磁性及机械性能的影响规律。揭示高氢压烧结的氢化机制及吸放氢反应的动力学规律。研究结果不仅为La(Fe,Si)13基磁制冷材料的实用化提供新思路和新工艺方法，而且为这类材料的实际应用提供理论和实验科学依据。

Regarding the practical applications of La(Fe, Si)13-based first order transition magnetocaloric bulk materials, the key scientific issues are of reducing the thermal and magnetic hysteresis, improving the ability of heat transfer and mechanical properties. In this project, the plate-shaped La(Fe,Si)13 hydrides will be synthesized by sintering in a self-made furnace in a high-pressure H2 atmosphere from starting material powders of both crushing arc melted ingots and melt-spun ribbons. The effects of duration or temperature of sintering and H2-pressures on crystal structures, phase components, phase transition temperature, compactness, the content and occupation of hydrogen atom, magnetic entropy changes and adiabatic temperature change of hydrides will be investigated systemically. The correlation between the structure of micropore, magnetic domain and hysteresis loss, thermal conductivities and brittleness will be analyzed and revealed. The influence of element doping, especially industrial mischmetal raw materials on magnetic properties, mechanical properties and hysteresis loss will be discussed. The forming mechanism in the high H2-pressure sintering and hydrogen absorption/desorption kinetics will be described. Based on the reduction of hysteresis, AMR machine-suitable refrigerants with high magnetic refrigeration performance will be synthesized. The new method and process route will be established. The research results can provide theoretical and technological bases for the application of the La(Fe,Si)13-based hydrides.