CAJ | 학술논문

通过熔体快淬制备了 Gd59 Co41、Gd56 Co44非晶条带,并对Gd56 Co44非晶条带进行588 K、10 min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,Gd59 Co41和 Gd56 Co44非晶条带的初始晶化温度分别为523和544 K；Gd56 Co44非晶条带晶化处理后获得了 Ho4 Co3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,Gd59 Co41和Gd56 Co44非晶合金的居里温度(TC )从198 K 提高到217 K；晶化处理后 Gd56 Co44合金的居里温度为218 K,与非晶态合金相比变化甚微.在ΔH＝5 T时, Gd59 Co41和Gd56 Co44非晶合金的最大磁熵变(-ΔSM)和制冷能力(RC)分别为7．7 J/kg·K、525 J/kg和6．6 J/kg·K、544 J/kg；而 Gd56 Co44晶态合金的最大磁熵变(-ΔSM)和制冷能力(RC)分别为5．6 J/kg·K 和528 J/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200 K温区附近一类具有潜在应用价值的磁制冷工质.
통과용체쾌쉬제비료 Gd59 Co41、Gd56 Co44비정조대,병대Gd56 Co44비정조대진행588 K、10 min적정화처리.이용 X 사선연사의(XRD)분석료합금적결구,통과종합물성측량계통(PPMS)연구료합금적자성급자열효응.결과표명,Gd59 Co41화 Gd56 Co44비정조대적초시정화온도분별위523화544 K；Gd56 Co44비정조대정화처리후획득료 Ho4 Co3형륙방단상.비정태화정태합금재거리온도부근도발생철자도순자적이급상변.수착Gd/Co비례적강저,Gd59 Co41화Gd56 Co44비정합금적거리온도(TC )종198 K 제고도217 K；정화처리후 Gd56 Co44합금적거리온도위218 K,여비정태합금상비변화심미.재ΔH＝5 T시, Gd59 Co41화Gd56 Co44비정합금적최대자적변(-ΔSM)화제랭능력(RC)분별위7．7 J/kg·K、525 J/kg화6．6 J/kg·K、544 J/kg；이 Gd56 Co44정태합금적최대자적변(-ΔSM)화제랭능력(RC)분별위5．6 J/kg·K 화528 J/kg.대적자적변화제랭능력,궤호가이홀략적교완력화열체/자체효응,표명 Gd-Co 이원비정화정태계렬합금시200 K온구부근일류구유잠재응용개치적자제랭공질.
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.