title: Enthalpy Effect of Adding Cobalt to Liquid Sn-3.8Ag-0.7Cu Lead-Free Solder Alloy: Difference between Bulk and Nanosized Cobalt.
abstract: Heat effects for the addition of Co in bulk and nanosized forms into the liquid Sn-3.8Ag-0.7Cu alloy were studied using drop calorimetry at four temperatures between 673 and 1173 K. Significant differences in the heat effects between nano and bulk Co additions were observed. The considerably more exothermic values of the measured enthalpy for nano Co additions are connected with the loss of the surface enthalpy of the nanoparticles due to the elimination of the surface of the nanoparticles upon their dissolution in the liquid alloy. This effect is shown to be independent of the calorimeter temperature (it depends only on the dropping temperature through the temperature dependence of the surface energy of the nanoparticles). Integral and partial enthalpies of mixing for Co in the liquid SAC-alloy were evaluated from the experimental data.
authors.affiliation: Department of Inorganic Chemistry (Materials Chemistry), University of Vienna, Währinger Str. 42, 1090 Vienna, Austria; Department of Metal Physics, Ivan Franko National University of Lviv, Kyrylo i Mephodiy str. 8, 79005 Lviv, Ukraine.
authors.forename: Andriy
authors.initials: A
authors.lastname: Yakymovych
authors.affiliation: Department of Nanotechnology, University of Miskolc, 3515 Miskolc-Egyetemváros, Hungary and Department of Materials Development, BAY-ENG , 2 Igloi, 3519 Miskolc, Hungary.
authors.forename: George
authors.initials: G
authors.lastname: Kaptay
authors.affiliation: Department of Inorganic Chemistry (Materials Chemistry), University of Vienna , Währinger Str. 42, 1090 Vienna, Austria.
authors.forename: Ali
authors.initials: A
authors.lastname: Roshanghias
authors.affiliation: Department of Inorganic Chemistry (Materials Chemistry), University of Vienna , Währinger Str. 42, 1090 Vienna, Austria.
authors.forename: Hans
authors.initials: H
authors.lastname: Flandorfer
authors.affiliation: Department of Inorganic Chemistry (Materials Chemistry), University of Vienna , Währinger Str. 42, 1090 Vienna, Austria.
authors.forename: Herbert
authors.initials: H
authors.lastname: Ipser