摘要
通过熔体快淬制备了Gd59Co41、Gd56Co44非晶条带,并对Gd56Co44非晶条带进行588K、10min的晶化处理。利用X射线衍射仪(XRD)分析了合金的结构,通过综合物性测量系统(PPMS)研究了合金的磁性及磁热效应。结果表明,Gd59Co41和Gd56Co44非晶条带的初始晶化温度分别为523和544K;Gd56Co44非晶条带晶化处理后获得了Ho4Co3型六方单相。非晶态和晶态合金在居里温度附近都发生铁磁到顺磁的二级相变。随着Gd/Co比例的降低,Gd59Co41和Gd56Co44非晶合金的居里温度(TC)从198K提高到217K;晶化处理后Gd56Co44合金的居里温度为218K,与非晶态合金相比变化甚微。在ΔH=5T时,Gd59Co41和Gd56Co44非晶合金的最大磁熵变(-ΔSM)和制冷能力(RC)分别为7.7J/kg·K、525J/kg和6.6J/kg·K、544J/kg;而Gd56Co44晶态合金的最大磁熵变(-ΔSM)和制冷能力(RC)分别为5.6J/kg·K和528J/kg。大的磁熵变和制冷能力,几乎可以忽略的矫顽力和热滞/磁滞效应,表明Gd-Co二元非晶和晶态系列合金是200K温区附近一类具有潜在应用价值的磁制冷工质。
Gd59 Co41 and Gd56 Co44 amorphous ribbons were prepared by arc melt spinning,and then Gd56 Co44 amorphous ribbon was crystallized at 588 K for 10 min.By means of X-ray diffraction （XRD）and physical prop-erty measurement system （PPMS）,the structure,magnetic properties and magnetocaloric effect of the alloys were investigated.The results show that the onset crystallization temperatures Tx for the Gd59 Co41 and Gd56 Co44 amorphous ribbons were found to be about 523 and 544 K,respectively.The Ho4 Co3-type hexagonal phase was obtained for crystallized Gd56 Co44 ribbons after annealing.All the amorphous and crystallized alloys undergo fer-romagnetic to paramagnetic second-order transition at their Curie temperatures.The Curie temperature （TC）of the amorphous Gd59Co41 and Gd56Co44 alloy enhances from 198 to 217 K with decreasing the Gd/Co ratio.And the TC of crystallized Gd56 Co44 alloy was 218 K,which has little change compared with that of the amorphous alloy.For a magnetic field change of 5 T,the maximum magnetic entropy change （-ΔSM）and refrigerant ca-pacity （RC）of Gd59 Co41 and Gd56 Co44 amorphous alloys were 7.7 J/（kg？？K）,525 J/kg and 6.6 J/（kg·K）, 544 J/kg,respectively.However,these values of crystallized Gd56 Co44 alloy are 5.6 J/（kg·K）and 528 J/kg. Large magnetic entropy change and magnetocaloric effect,negligible coercive force and thermal/magnetic hys-teresis make Gd-Co binary amorphous and crystallized alloys as the potential candidates for the magnetic refrige-ration materials working in the vicinity of 200 K.
出处
《功能材料》
EI
CAS
CSCD
北大核心
2014年第B06期111-116,共6页
Journal of Functional Materials
基金
教育部留学回国人员科研启动基金资助项目(x2clB7120290)
中央高校基本科研业务费专项资金资助项目(2014ZZ0005
2012ZZ0013)
广州市科技计划资助项目(12F582080022)
广东省科技计划资助项目(2010B050300008
2007B010600043)
关键词
磁制冷材料
熔体快淬
Gd-Co
合金
磁熵变
磁热效应
magnetic refrigeration material
melt-spun
Gd-Co binary alloy
magnetic entropy change
magnetoca-loric effect
