Magnetocaloric effect of Ni-Fe-Mn-Sn microwires prepared by melt-extraction technique. (15th January 2017)

• Record Type: Journal Article
• Authors: Zhang, Hehe; Qian, Mingfang; Zhang, Xuexi; Jiang, Sida; Wei, Longsha; Xing, Dawei; Sun, Jianfei; Geng, Lin
• Is Part Of: Materials & design. Volume 114(2017)
• Page Start: 1
• Page End: 9
• Publication Date: 2017-01-15
• Subjects: Ferromagnetic shape memory alloys -- Microwires -- Martensitic transformation -- Magnetocaloric effect -- Ni-Fe-Mn-Sn; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2016.10.077
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Small-sized materials with large surface to volume ratio favor heat transfer during magnetic refrigeration cycling and thus may help enhancing the refrigeration efficiency. Here, high Fe content Ni44.9 Fe4.3 Mn38.3 Sn12.5 polycrystalline microwires were prepared by a melt-extraction technique. The as-extracted microwires were annealed at 1173 K for 60 min, leading to significant grain growth and formation of a secondary Fe-rich γ phase. The annealed microwire exhibits larger magnetization difference ( ΔM ) between the austenite and martensite phases and smaller thermal hysteresis compared to the as-extracted microwire. The annealed microwire possesses a magnetic transition to austenite at 299 K, followed by a martensitic transformation (MT) from a ferromagnetic austenite to a weak-magnetic martensite at 208 K upon cooling. Under a magnetic field of 50 kOe, the annealed microwires show a maximum magnetic entropy change ΔS m of 6.9 J/kg·K and an effective refrigeration capacity RC eff of 78.0 J/kg over a broad working temperature span ΔT FWHM of 20 K around the MT. In addition, magnetic transition of the austenite gives rise to ΔS m − 3.7 J/kg·K and RC mag 232.5 J/kg with ΔT FWHM of 85 K under 50 kOe. Graphical abstract: Highlights: Ni44 .9 Fe4.3 Mn38.3 Sn12.5 microwires with diameter 40-80 μm were fabricated on a large scale. The magnetization difference between austenite and martensite phase was enhanced after annealing. The wires produce magnetic entropy change 6.9 J/kg·K with 20 K cooling span due to martensite transformation at 50 kOe. The wires show magnetic entropy change -3.7 J/kg·K and working temperature span 85 K due to magnetic transition at 50 kOe.