Phase equilibria in the Sn–Zn–Ni system

Abstract

Abstract The objective of this study is to elucidate the phase equilibria of the Sn–Zn–Ni system. For this purpose, ternary alloys were synthesized using quartz ampoules and annealing. The samples were characterized using differential scanning calorimetry, X-ray diffraction, optical and scanning electron microscopy and microhardness measurements. The results show relatively significant solubility of tin or zinc (about 10 at.% roughly) in Ni–Zn and Ni–Sn phases, respectively. Moreover, evidence of the presence of two formerly unknown ternary compounds denoted as T1 and T2 was found. The first one has a composition (mole fraction) of about: X Sn = 0.38 ± 0.04, X Ni = 0.36 ± 0.02, X Zn = 0.26 ± 0.03 while the approximate composition of the second is X Sn = 0.26 ± 0.03, X Ni = 0.55 ± 0.00, X Zn = 0.19 ± 0.03. Three unidentified compositions were observed: U1 (X Sn = 0.26 ± 0.07, X Ni = 0.29 ± 0.03, X Zn = 0.45 ± 0.04), U2 (X Sn = 0.55 ± 0.01, X Ni = 0.21 ± 0.00, X Zn = 0.24 ± 0.01), and U3 (X Sn = 0.48 ± 0.05, X Ni = 0.08 ± 0.00, X Zn = 0.44 ± 0.05) but there was still a lack of evidence to categorize any of them as a ternary compound. A tentative isothermal section of the Sn–Zn–Ni phase diagram at 600 °C was constructed.