Structural, thermal and optical studies of Ni 3Se 2 compound produced by mechanical alloying

Abstract

The Ni 3Se 2 compound was obtained by mechanical alloying starting from a binary mixture of pure crystalline powders with nominal composition Ni 75Se 25. X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC) and Raman scattering (RS) techniques were used to follow the structural, thermal and optical properties of the binary mixture as a function of milling time. XRD results showed the formation of trigonal Ni 3Se 2 phase from 3 up to 70 h of milling coexisting with non-reacted fcc-Ni phase. DSC and RS results showed high stability of the thermal and optical properties of the Ni 3Se 2 phase when the milling time increases. The Raman active modes of the Ni 3Se 2 phase, which are missing in the literature, were determined. No other phases, such as iron selenides, nickel oxides and selenium oxides, were detected.