Effect of the preparation method on the structural and magnetic properties of the Fe2Nb alloy

Abstract

In this paper we carried out the structural and magnetic study of the Fe2Nb stoichiometric alloy by means of x‐rays diffraction and Mössbauer spectrometry. The samples were obtained by two different techniques, arc‐melting and mechanical alloying, and then they were thermally treated. The structural properties of the alloy depend on the method of preparation: by the melting method it was possible to obtain the hcp‐Fe2Nb ordered structure; while by mechanical alloying besides of the hcp structure also were formed the fcc‐NbO and bcc‐FeNb structures. After heat treatment of the melted alloy, this was submitted to mechanical alloying during 16 and 32 hours. Mechanical alloying allows the formation of bcc‐FeNb grains which behave as superparamagnetic due to their small size and they are surrounded by hcp grains. Before heat treatment of the alloy obtained by mechanical alloying it was also found the existence of superparamagnetic bcc grains and the heat treatment increases the size of these bcc grains and the superparamagnetic‐ferromagnetic transition is induced.