Retaining the Curie temperature of Ce substituted Nd-Fe-B nano-ribbons by Alnico elements substitution

Abstract A balanced consumption of the rare earth resources can be realized by increasing the content of Ce in Nd-Fe-B magnetic alloys. However, the substitution of Ce for Nd reduces the magnetic properties and the Curie temperature of the 2:14:1 phase resulting in limited application fields. In this manuscript, targeting to increase the Curie temperature by maintaining the magnetic properties at acceptably high level, Fe in 25% Ce substituted Nd-Ce-Fe-B alloys has been substituted by Alnico constituent elements. The Curie temperature of the main phase for 25% Ce substitution (544 K) is enhanced to 589 K by 20% Alnico substitution which is higher than the Curie temperature of the pure Nd2Fe14B compound (⁓585 K). The magnetic properties initially increased as a result of Alnico element substitution, and then slightly decreased. Maximum energy density of 100 kJ/m3 and Curie temperature of 582 K is obtained by substituting 15% Alnico. These properties are comparable to Ce-free Nd-Fe-B melt spun alloys. The working temperature range increased by the increase of Curie temperature and the decrease of spin reorientation temperature. Due to the accumulation of ferromagnetic element, Ni, at the grain boundary and triple junction phases and the refined grains, the short-range exchange interactions among the nanograins increased which helped to obtain high energy density in the alloys.