Thermochemical and phase diagram studies of the Bi–Ni–Sn system

• Published in: Thermochimica acta 2012-04, Vol.534, p.41-50
• Main Authors: Milcheva, N., Broz, P., Buršík, J., Vassilev, G.P.
• Format: Article
• Language: English
• Subjects: ambient temperature; Annealing; Bi–Ni–Sn phase diagram; calorimetry; Chemical thermodynamics; Chemistry; Differential scanning calorimetry; DSC; electron microscopy; Eutectic temperature; Exact sciences and technology; General and physical chemistry; General. Theory; Liquidus; Mathematical analysis; Moles; nickel; Phase diagrams; physical phases; Scanning electron microscopy; SEM; silica; Solders; spectroscopy; temperature; Ternary eutectic reaction; tin; X-ray diffraction
• ISSN: 0040-6031; 1872-762X
• DOI: 10.1016/j.tca.2012.02.011

► We study the phase diagram Bi–Ni–Sn by using scanning electron microscopy and differential scanning calorimetry. ► The samples are positioned in 3 isopleths with constant Ni contents of 0.05, 0.10 and 0.15mol fraction. ► It has been confirmed that a ternary eutectic reaction appears at around 116–129°C. ► Experimental liquidus temperatures were obtained and compared to calculated ones. ► Six groups of thermal arrests were registered (except the eutectic and liquidus related peaks). The phase diagram Bi–Ni–Sn was studied by means of SEM (scanning electron microscopy)/EDS (energy-dispersive solid state spectrometry), by DSC (differential scanning calorimetry) and RT-XRD (room temperature X-Ray diffraction) in order to attain more information about this ternary phase diagram. The samples were positioned in three isopleths with nickel contents of: 0.05 (section 1), 0.10 (section 2) and 0.15 (section 3) mole fractions, respectively. The mole fractions of Sn corresponding to the particular sections were as follows: from 0.19 to 0.76 (section 1), from 0.18 to 0.72 (section 2); from 0.17 to 0.68 (section 3). Mixtures of pure metals were sealed under vacuum in amorphous silica ampoules and annealed at 350°C. A binary Bi–Sn eutectic sample was synthesized and used as internal standard. The existence of a previously reported ternary eutectic reaction was confirmed. Liquidus temperatures were identified and the results were compared to CALPHAD-type calculations. It was found that ternary samples’ liquidus temperatures were higher than the calculated ones. Six more groups of thermal arrests were registered except the eutectic and liquidus related peaks.