Abstract
Solid∕liquid two-phase structures in isolated nanometer-sized alloy particles have been studied by transmission electron microscopy. The microstructure developed in the crystal+liquid two-phase region was different between particles in the Au-Sn and Bi-Sn systems; namely, a core (crystal)-shell (liquid) structure appeared in the former system, whereas a simple two-phase structure with a planar interface separating the crystalline and liquid phases in the latter system. The reason for the difference between the two alloy systems is discussed in terms of the relative contributions of the surface energy of solid, the surface energy of liquid, and the inferface energy to the total Gibbs free energy of a particle.