一级相变磁热效应材料磁制冷能力和效果的研究

项目名称： 一级相变磁热效应材料磁制冷能力和效果的研究

项目编号： No.51261001

项目类型： 地区科学基金项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 黄焦宏

作者单位： 包头稀土研究院

项目金额： 52万元

中文摘要： 目前具有巨磁热效应的室温磁制冷材料均为一级磁相变材料。由于一级相变材料的等温磁熵变是通过测量M-H曲线并经过Maxwell关系式计算得到的，其计算方法一直有很大的争议。本项目采用一级相变材料La(FeSi)13HX、Gd5Si2Ge2、 MnFeP(SiGe)及二级相变材料金属Gd和La(FeCoSi)13BX的球形颗粒或不规则颗粒（颗粒直径相同）作为研究对象，在经过改进的自制磁热效应直接测量仪上测量样品在磁场内外的吸、放热量和弛豫时间，测量研究一级与二级相变材料在磁制冷的每次循环制冷所吸收和释放的热量；在室温磁制冷机上进行磁制冷实验，测量研究最大制冷温差、最大制冷功率及磁相变点与环境温度对制冷温差、制冷效果的影响等，并分别与它们的熵变与温变进行对比，进一步研究磁滞和热滞对一级相变材料制冷效果的影响等，确定一级磁相变材料是否有巨大的磁熵变，确定一级相变磁热效应材料的实际制冷能力和制冷效果。

中文关键词： 磁热效应；相变；弛豫时间；制冷能力；

英文摘要： Currently, the room temperature giant magnetocaloric materials which have been found so far are all first order magnetic phase transition materials. The calculation method of calculating the isothermal magnetic entropy change is still a disoloved proplem, because the isothermal entropy change is obtained from M-H curves by Maxwell eqution. The matereials of study in the proposed research are spherical particles and irregular particles(with the same diameter) of the first order phase transition materials La(FeSi)13HX, Gd5Si2Ge2, MnFeP(SiGe) and the second order phase transition materials Gd, La(FeCoSi)13BX. Endotherm, exothermthe and relaxation time of the particles will be measured directly by an improved magnetocaloric effect measurement apparatus upon the cycling of external magnetic fields. All the samples will be tested on magnetic refrigerator. The largest refrigeration temperature difference, the largest refrigeration power and influence of magnetic phase transiton point and environment temperature will be measured and studied. The results will be compared with their isothermal entropy change and adiabatic temperature change,respectively. Then we further explore the influence of magnetic hysteresis and thermal hysteresis on magnetic refrigeration effect. We will determine if the first order phase transiti

英文关键词： magnetocaloric effect；phase transition；relaxation time；refrigerating capacity；