Thermal chemistry and short-range order in Co-Sb melts

Abstract

The enthalpies of mixing for the liquid Co-Sb alloys are measured by isoperibolic calorimetry at 1600 K over the whole concentration range relative to liquid Sb and undercooled liquid Co. The minimal integral enthalpy of mixing is −6.3 ± 0.6 kJ/ mole at x Co = 0.50. Activity of components, Gibbs energy, and the entropy of mixing are calculated using a short-range ordering model considering CoSb associates formed in molten Co-Sb alloys.

Enthalpies of mixing of liquid systems for lead free soldering: Co–Sb–Sn

“…Our measurements confirm the generally exothermic enthalpy of mixing for Co–Sb found by Ivanov et al. [5] . However, the minimum of −13000 J/mol is much lower.…”

“…This could be caused by the lower temperature of 1273 °C compared to 1600 K in Ref. [5] . Additionally, it is not clear if the authors accounted for the rather strong enthalpy of ferro-/paramagnetic transition (∼8500 J/mol, according to [21] ).…”

“…Ivanov et al. [5] have measured the enthalpy of mixing of liquid Co–Sb alloys by isoperibolic calorimetry at 1600 K and, for Co-rich alloys only, at 1800 K. The values presented show a generally exothermic effect with a minimum of −6270 J/mol at approx. 50 at.% Co.…”