Melting Temperature of Metallic Nanoparticles

Abstract

Melting temperature is one of the fundamental properties of materials. In principle, the melting temperature of a bulk material is not dependent on its size. However, as the size of a material decreases toward the nanometer size and approaches atomic scale, the melting temperature scales with the material dimensions. The melting temperature of a nanomaterial such as nanoparticles (isotropic) and nanorods/nanowires (anisotropic) is related to other fundamental physical properties for nanomaterial applications, including catalysts, thermal management materials, electronics materials, and energy materials.This book chapter focuses on both the theoretical and experimental studies of metallic nanoparticle melting temperature depression. Thermodynamic modeling and molecular dynamic (MD) simulations are discussed regarding the melting behavior of different nanostructures, such as spherical nanoparticles and nanowires. The currently available measurement techniques by using classical differential scanning calorimetry (DSC), recently developed nanocalorimeters, transmission electron microscope (TEM), and optical methods are introduced. In addition, the applications of metal nanoparticles with lower melting temperatures are discussed, such as nanosoldering and sintering for electronics assembly and packaging.

From metal nanowires to ultrathin crystalline ALD nanotubes: process development and mechanism revealed by in situ TEM heating experiments

“…39 Decreasing the size of materials down to the nanometer range also leads to a decreasing melting temperature. 40 By applying the thermodynamic model to calculate the melting temperature for NWs derived by Sar et al , 41 the nano-size copper has a melting temperature of around 1010 °C. This is in accordance to our experiments, as we do not observe the formation of liquid phases.…”

Observation of Bismuth Nanoparticle Premelting by Slow and Ultrafast Laser Heating

“…Among the physical properties of materials that are affected by size reduction to the nanoscale is the melting point, which is generally found to be lower than their bulk melting point, T m . − The reduction of the melting point of nanoparticles (NPs) from T m is attributed to the increased number of surface atoms at the expense of core atoms. For instance, Buffat and Borel found that the melting point of gold NPs could be hundreds of degrees less than the T m of gold .…”

Melting and Structural Dynamics of Indium Nanoparticles Embedded in Aluminum

“…Solids with reduced dimensionalities, such as nanoparticles (NPs), have properties that can deviate from their bulk materials. Among the properties that depend on size is the melting point, which is reduced with NP size. − Understanding the melting of NPs is important for the development of better models of phase transitions at the nanoscale and for the applications of NPs at elevated temperatures. When the size of a solid particle decreases, its surface-to-volume ratio increases.…”