Low-Temperature Melting of Silver Nanoparticles in Subcooled and Saturated Water

Low-Temperature Melting of Silver Nanoparticles in Subcooled and Saturated Water

TitleLow-Temperature Melting of Silver Nanoparticles in Subcooled and Saturated Water
Publication TypeJournal Article
Year of Publication2016
AuthorsSoochan Lee, Patrick E Phelan, Robert A Taylor, Ravi S Prasher, Lenore Dai
JournalJ. Heat Transfer
Volume138
Pagination052301
Date Published01/2016
Keywordslasers, melting, Nanofluids, nanoparticles, particulate matter, silver, Subcooling, temperature, water
Abstract

Continuous, laser-heated boiling heat transfer experiments with silver nanofluids were conducted to identify the nonequilibrium melting behavior of silver nanoparticles in de-ionized (DI) water. Experimental results with transmission electron microscopy (TEM) and dynamic light scattering (DLS) suggest that surface melting of silver nanoparticles (which have a bulk melting point of 961 °C) can occur at ambient pressure when particles are suspended in saturated, and even subcooled (e.g., <100 °C) water due to the localized (volumetric) heat absorption. These findings are supported by calculating a temperature-dependent Hamaker constant of silver nanofluid—i.e., the interaction between interfaces (Ag-melt-water) at the melting temperature. This finding is significant because of the difficulty to identify the melting of silver nanoparticles in water at present, even though it is important to understand such potential melting to use aqueous silver nanofluids in solar applications.

DOI10.1115/1.4032310