Modeling thermodynamic properties of Ni, Sn, Al and Cu nanosolids
Madan Singh, Benedict M. Taele, Sekhantso Lara, Sanjay Kumar Singhal and Kamal Devlal
Surface atoms and dangling bonds on the surface affect the thermodynamic properties. A thermodynamical model, based on cohesive energy is presented to discuss the melting properties of materials at nanoscale. The model is used to realize the effect of size and shape on melting temperature Tmn, melting entropy Smn and enthalpy Hmn of Ni, Sn, Al and Cu metallic nanoparticles. The variation in Tmn, Smn and Hmn are examined for nanowire, film, spherical, regular tetrahedral, hexahedral and octahedral shaped nanoparticles. It is reported that Tmn, Smn and Hmn decrease with decreasing the size of the nanoparticles and smaller the particle size, greater are the size and shape effects and when size is less than 10 nm, it has been predicted that on decreasing size, Tmn, Smn and Hmn reduce appreciably. Also, at the same size, more the shape of nanoparticles departs from that of the sphere, smaller is the Smn and Hmn of nanoparticles and its changes are less for nanowire shape and more for regular tetrahedral shape. Our theoretical results are compared with the available experimental or simulation data. Results predicted by our model are in good agreement with experimental observations.
Keywords: Cohesive energy, nanostructures, melting temperature, bond theory, surface energy, size effect
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