Density-Functional-Theory study of cohesive, structural and electronic properties of Ni-Sb intermetallic phases

C. DELUQUE TORO; S.B. RAMOS; A. FERNÁNDEZ GUILLERMET

Santos

Congreso; Discussion Meeting on Thermodynamics of Alloys - TOFA 2016; 2016

Universidad de San Pablo

Current environmental requirements for the development of Pb-free solders have led to the systematic search for replacements of the traditional Pb-Snalloys. As a consequence, various Me-X systems (with Me=Cu,Ni and X=In,Sn) have recently been studied theoretically, in particular, by the present authors [1-3]. The aim of the research line is to develop a complete database with structural, thermodynamic, cohesive and elastic properties of the intermetallic phases (IPs) of interest in the design of new lead-free soldering alloys and in the establishment of correlations between these properties and the electronic structure. In particular, Ramos et al. [3] performed a systematic comparative study of the electronic and cohesive properties of the Cu-In, Cu-Sn, Ni-In and Ni-Sn systems. In addition, there have been attempts by the present group to incorporate some IPs formed by Sb. Firstly, we focused on a new Cu5+xIn2+xSb2-x B8 related structure [4]. Secondly, we studied the physical properties of the Ni3Sb phase [5]. The purpose of this work is to add to the understanding of the thermophysical properties of the remaining IPs of the Ni-Sb system. In addition to the Ni3Sb(oP8) structure, the following IPs have been reported for the Ni-Sb system: Ni5Sb2(mC28), Ni7Sb3 (unknown), NiSb (hP4) and NiSb2(oP6). Recently, Xiao et al. [6] performed low temperature resistivity measurements on polycrystalline samples of four of these compounds: Ni3Sb,Ni5Sb2, NiSb, and NiSb2. In addition, ab initio calculations for the same IPs were performed. The results were found to be consistent with those predicted by the first-principle electronic structure calculations. In the present work, the values at 0 K of properties such as molar volume, bulk modulus and its pressure derivative, the electronic density of states, and the energy of formation from the elements of several stable compounds of the Ni3Sb,Ni5Sb2, NiSb, and NiSb2 IPs were established theoretically. The calculations were made in the framework of the density functional theory, using VASP (Vienna Ab Initio Simulation Package) and the Projected Augmented Waves (PAW) method. The results of the work are discussed in the light of the picture of the bonding trends developed in previous works by us. [1] S. Ramos de Debiaggi et al., J. Alloys and Compds. 542 (2012) 280.[2] S. Ramos de Debiaggi et al., J. Alloys and Compds. 576 (2013) 302. [3] S.B. Ramos et al., J.Phys. Chem. Sol. 93 (2016) 40. [4] C.J. Müller et al., Inorg. Chem., 51 (2012) 10787. [5] C.E. Deluque Toro et al., Mater. Res. Soc.Proceedings Vol. 1816 (2016). [6] L.Xiao-Ning et al.,Chin. Phys. B (2015) 24(6) 67201.