摘要
磁制冷技术是一种高效节能、绿色环保、可靠性强的先进制冷技术,其核心原理是磁性材料的磁热效应,即磁制冷工质等温磁化时向外界放出热量,绝热退磁时从外界吸收热量。理论上所有的磁性材料都具有磁热效应,但只有极少数具有显著磁热效应的磁性材料可用于磁制冷。因此,研发具有较大磁热效应的磁制冷工质是决定磁致冷技术能否得到应用和推广的关键因素。经过几十年的发展,人们陆续发现了许多性能优异的磁制冷材料,推动和促进了磁制冷技术的发展。目前,磁制冷技术在20 K以下的低温区已经得到了较为广泛的应用,如液氦的制备、低温物理研究以及航空航天等领域都采用了磁制冷技术。低温区的磁制冷材料通常为顺磁状态,其构型熵可以忽略不计,但随着温度的升高,用于低温区磁制冷的顺磁材料的晶格振动变大,构型熵对磁制冷系统的影响不可忽略,即传统的顺磁态磁制冷工质在近室温区已不再适用,因此研发近室温区的磁制冷材料具有重要意义。近20年间,国内外研究者对近室温区磁制冷材料进行了大量研究并取得了许多重要成果,如以Gd(SiGe)_(4)、La(FeSi)_(13)、MnAs合金和NiMn基Heusler合金等为代表的具有优异磁热效应的一级相变磁制冷材料,这些合金的磁热效应通常是由结构相变与磁相变的叠加引起的,但常常伴有较大的热滞与磁滞损耗,进而会大幅度降低磁制冷的效率。除了一级相变磁制冷材料外,还有稀土Gd及其化合物、Gd基非晶态合金等具有二级磁相变的近室温磁制冷材料。其中,Gd基非晶态合金具有制冷温区宽、涡流损耗低、磁滞低、成分范围宽、耐腐蚀和易于加工等优点,其较宽的制冷温区特别适合室温埃里克森磁制冷循环,具有广阔的应用前景。本文简要介绍了磁热效应的原理以及磁制冷技术的发展,重点介绍了近室温磁制冷材料
Magnetic refrigeration technology is an advanced refrigeration technology with high efficiency,energy saving,environmental protection,and strong reliability.The core principle of the magnetocaloric effect is the physical phenomenon of that heat was released to the outside during isothermal magnetization and absorbed from the outside during adiabatic demagnetization of the magnetic refrigerant.Theoretically,all magnetic materials have the magnetocaloric effect.However,only a few magnetic materials with significant magnetocaloric effect can be used in magnetic refrigeration.Therefore,the research and development of magnetic refrigeration working medium with a larger magnetocaloric effect is the key factor to determine whether the magnetic refrigeration technology can be applied and promoted.After decades of development,many excellent magnetic refrigeration materials have been found,which promotes the development of magnetic refrigeration technology.At present,the magnetic refrigeration technology has been widely used,such as in the preparation of liquid Helium,low temperature physical research,and aerospace engineering,in the low temperature region below 20 K.The configurational entropy of magnetic refrigeration materials can be ignored in low temperature region as they are usually in paramagnetic state.However,with the temperature increasing,the influence of configurational entropy on the magnetic refrigeration cannot be ignored attributed to the lattice vibration of the paramagnetic materials becomes larger.So,the traditional paramagnetic refrigerant is no longer applicable near room temperature.Therefore,it is important to develop magnetic refrigeration materials near room temperature.In the past two decades,lots of studies on magnetic refrigeration materials near room temperature have carried out,such as the magnetic refrigeration materialsincluding Gd(SiGe)_(4),La(FeSi)_(13),MnAs alloy,and NiMn based Heusler alloy,and all those alloys present the first-order phase change and excellent magnetocaloric effect.The
作者
李冬梅
左定荣
余鹏
LI Dongmei;ZUO Dingrong;YU Peng(Photoelectric Functional Materials Key Laboratory of Chongqing,College of Physics and Electronic Engineering,Chongqing Normal University,Chongqing 401331,China)
出处
《材料导报》
EI
CAS
CSCD
北大核心
2021年第11期11119-11125,共7页
Materials Reports
基金
重庆市基础研究与前沿探索项目(cstc2018jcyjAX0329,cstc2018jcyjAX0444)
重庆市教委科学技术研究重点项目(KJZD-K201900501)。
关键词
近室温磁制冷
磁热效应
磁制冷材料
磁熵变
非晶态合金
magnetic refrigeration near room temperature
magnetocaloric effect
magnetic refrigeration material
magnetic entropy change
amorphous alloy
