A thermodynamic assessment of Ni–Sb system

The Ni–Sb system was critically assessed by means of the CALculation of PHAse Diagram (CALPHAD) technique. The solution phases, Liq and (αNi), were modelled as the substitutional solutions with the Redlich–Kister equation. The intermediate phases, (γNiSb) and (βNi3Sb), with homogeneity ranges were described respectively using three-sublattices (Sb)1/3(Ni%,V a)1/3(V a%,Ni)1/3 and (Sb)1/4(Ni%,V a)1/2(Ni%,V a)1/4 based on their structure features. Corresponding to the phase (βNi3Sb), the two low-temperature phases of (δNi3Sb) and (θNi5Sb2) with narrow homogeneity ranges were modelled as two-sublattice, (Ni)3/4(Sb,Ni)1/4 and (Ni)5/7(Sb,Ni)2/7. The intermetallic compound ζNiSb2 with no homogeneity ranges was treated as stoichiometric compound. The phase εSb was considered as pure Sb for the solubility of Ni in εSb is very low. A set of self-consistent thermodynamic parameters of the Ni–Sb system was obtained. The optimized phase diagram and thermodynamic properties were presented and compared with experimental data.