The nano heat effect of replacing macro-particles by nano-particles in drop calorimetry: the case of core/shell metal/oxide nano-particles. Issue 16 (27th February 2018)

• Record Type: Journal Article
• Authors: Yakymovych, A.; Kaptay, G.; Flandorfer, H.; Bernardi, J.; Schwarz, S.; Ipser, H.
• Is Part Of: RSC advances. Volume 8:Issue 16(2018)
• Page Start: 8856
• Page End: 8869
• Publication Date: 2018-02-27
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7ra13643a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Difference in the enthalpy effect by replacing micro- by nano-sized particles in drop calorimetry. Abstract : Experimental results are presented here obtained by a drop calorimetric method, in which Ni and Cu particles, both in bulk and nanosized form, were dropped into a liquid Sn-3.8Ag-0.7Cu solder alloy (in wt%). The molar enthalpies of mixing of the liquid (Sn-3.8Ag-0.7Cu)–Ni(Cu) alloys were measured. An extra exothermic heat effect is observed when dropping nano-particles instead of macro-particles. This is partly due to the loss of the large surface area and the corresponding large surface enthalpy of the nano-particles before their dissolution in the liquid alloy. However, a large additional exothermic heat effect was also found in the case of Cu-nano-particles, due to the exchange chemical reaction between the Cu2 O shell of the nano-particles and liquid Sn; this is caused by the fact that the Cu-nano-particles are core–shell particles with an inner metallic Cu core and an outer Cu2 O shell. This effect is less significant for Ni nano-particles which have a thinner oxide shell.