The crystallisation kinetics, magnetic and magnetocaloric properties of Gd55Co20Fe5Al20 - xSix (x=0, 5, 10, 15) alloys
Küçük Resim Yok
Tarih
2013
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
The effects of substituting Si for Al on the crystallisation kinetics and magnetic and magnetocaloric properties of Gd55Co20Fe5Al20 Si-- x(x) (x = 0, 5, 10, 15) alloys have been investigated in detail. The broad diffraction peaks in the XRD patterns indicated that all the samples have amorphous structures. The activation energies of the alloys were calculated using the Kissinger, Ozawa and Augis-Bennett models based on differential thermal analysis data. The Avrami exponent n was calculated from the Johnson-Mehl-Avrami equation. The increase in the activation energy as the Si content increased to x = 10 indicated that the addition of Si improves the thermal stability and slows the crystallisation kinetics of the samples. The value of the Avrami exponent showed that the nucleation and growth mechanisms of the crystallisation process depend on the Si concentration. The maximum entropy change reached a maximum value of 6.82 J/kg K for x = 5 and then decreased with further increases of Si. The refrigeration capacities are 558, 665,700 and 519 J/kg for x = 0, 5, 10 and 15, respectively. The increased thermal stabilities and large refrigeration capacities make these amorphous alloys attractive candidates for magnetic refrigeration applications. (C) 2013 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
Amorphous alloys, Crystallisation kinetics, Magnetocaloric effect
Kaynak
Journal of Non-Crystalline Solids
WoS Q Değeri
Q1
Scopus Q Değeri
Q2
Cilt
379
