磁热效应材料的研究进展

磁制冷技术的发展取决于具有大磁热效应磁制冷材料的研发进展.经过长期的工作积累,特别是近20年来的努力,许多新型磁制冷材料的探索和研究极大地促进了磁制冷技术的进步.本文介绍了磁热效应的基本原理和磁制冷研究的发展历史,系统综述了低温区和室温区具有大磁热效应的磁制冷材料的研究进展,重点介绍了一些受到较为关注的磁热效应材料的最新研究成果.低温区磁制冷材料主要包括具有低温相变的二元稀土基金属间化合物(RGa,RNi,RZn,RSi,R_3Co以及R_(12)Co_7)、稀土-过渡金属-主族金属三元化合物(RTSi,RTAl,RT_2Si_2,RCo_2B_2,RCo_3B_2)以及四元化合物RT_2B_2C等,其中R代表稀土元素,T代表过渡金属.这些材料一般都具有二级相变,具有良好的热、磁可逆性,也因其合金属性具有良好的导热性.室温区磁制冷材料主要包括Gd-Si-Ge,La-Fe-Si,Mn As基,Mn基Husler合金,Mn基反钙钛矿,Mn-Co-Ge,Fe-Rh以及钙钛矿氧化物等系列.这些材料一般都具有一级相变,多数在室温具有巨大的磁热效应而受到国内外的极大关注.其中,La-Fe-Si系列是国际上普遍认为具有重要应用前景的磁制冷工质之一,也是我国具有自主知识产权的材料.本文还对磁制冷材料的发展方向进行了展望.

Research progress in magnetocaloric effect materials

Magnetocaloric effect（MCE) is the intrinsic property of a magnetic material near transition temperature and the magnetic refrigeration based on MCE has been demonstrated as a promising alternative to the conventional gas compression or expansion refrigeration due to its high energy efficiency and environmental friendliness. The development of magnetic refrigeration technology depends on the research progress of magnetic refrigerant materials with large MCEs. Lots of researches of material exploration and material optimization have promoted the progress of magnetic refrigeration technology in recent decades. In this paper, we introduce the basic theory of MCE and the development of refrigeration technology, review the research progress of large MCE materials both in low temperature range and in room temperature range, and specifically focus on the latest progress of some MCE materials. Low temperature MCE materials mainly include those rare earth based materials with low transition temperatures, such as binary alloys（RGa, RNi, RZn, RSi, R₃Co and R₁₂Co₇), ternary alloys（RTSi, RTAl, RT₂Si₂, RCo₂B₂ and RCo₃B₂), and quaternary alloys（RT₂B₂C), where R denotes the rare earth and T represents the transition metal. Those materials mainly possess the second-order phase transitions and show good thermal hysteresis, magnetic hysteresis, and thermal conductivities. Room temperature MCE materials are mainly Gd-Si-Ge intermetallic compounds, La-Fe-Si intermetallic compounds, MnAs-based compounds, Mn-based Heusler alloys, Mn-based antiperovskite compounds, Mn-Co-Ge intermetallic compounds, Fe-Rh compounds, and perovskite-type oxides. The above materials usually have the first-order phase transitions and most of these materials possess the large MCEs in room temperature range, therefore they have received much attention home and abroad. Among those room temperature MCE materials, the La-Fe-Si series is considered to be the most promising magnetic refrigerant materials universally and our country has independent intellectual property rights of them. The further development prospects of MCE materials are also discussed at the end of this paper.