NaZn13型La-Fe-Si(H,C)泡沫材料的制备、磁性和磁热效应研究

项目名称： NaZn13型La-Fe-Si(H,C)泡沫材料的制备、磁性和磁热效应研究

项目编号： No.11204147

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学I

项目作者： 王芳

作者单位： 宁波工程学院

项目金额： 30万元

中文摘要： 高铁含量的NaZn13型La-Fe-Si及其间隙化合物因价格低廉、磁热性能优良而备受关注。但一级相变过程引起的磁和热滞后以及较大的内应力不利于其在磁制冷样机中的应用。而微观结构对相变性质有较大影响；理论计算表明：泡沫结构可有效提高磁制冷工质与蓄冷液间的热交换效率。我们将尝试采用铸造复制和粉末冶金造孔剂法制备具有泡沫结构的La-Fe-Si（H,C）新材料，通过微观结构、磁和热等性能的测量、分析，并结合La-Fe-Si块体材料已有研究成果，澄清微观结构特征如孔隙率、孔隙大小等对材料相转变、磁热效应、磁和热滞后、内应力、制冷工质与蓄冷流体间热交换效率等的影响。揭示微观结构、相变性质、磁（热）滞后之间的联系。成功制备在中高温区尤其是温区附近具有大磁热效应、制冷性能优良的La-Fe-Si泡沫材料，对发发展具有我国自主知识产权的磁制冷新材料，对磁制冷技术的应用和基础研究都将具有非常重要的意义。

中文关键词： 磁性；磁热效应；泡沫；临界行为；非晶

英文摘要： NaZn13-typed La-Fe-Si and their interstitial compounds have attracted much attention due to the low cost and their large magnetocaloric effect. The magnetic, thermal hysteresis and the large internal stress induced by its first order phase transition nature, howerver, are not conducive to its application in magnetic refrigerator. The microstructure has significant effects on the phase transition nature. The heat exchange efficiency between the refrigerant and the cold storage fluid will be improved in the foamed materials, which is very improtan in the application of the magnetic refrigeration technology. . Through this project, we would try to prepare the La-Fe-Si and their interstitial compounds with a foam structure by the replication processe. Through the measurements and analysises about the microstructure and magnetic, thermal properties of the foamed and bulk materials, the effects of microstructure such as porosity , pore size etc. on the phase transition, magnetocaloric effect, magnetic and thermal hysteresis, internal stress and other properties as well as the heat exchange efficiency of refrigerant with cold storage fluid will be studied. We try to find out the relationship between the microscopic structure and the phase transition, the large magnetocaloric effect, and reveal its physical mechanism.

英文关键词： magnetic properties；magnetocaloric effect；foam；critical behavior；metallic glass