Effect of high heating rates on the melting behavior of embedded In nanoparticles

Abstract

In nanoparticles embedded in an Al-rich polycrystalline matrix have been investigated concerning the kinetics of their melting behavior. The advantage of the present system lies in the fact, that two distinct populations of particles are intrinsically formed: facetted nanoparticles that are embedded within the matrix grains and that obey the facetted Wulff shape or slight deviations thereof and particles situated at the grain boundaries of the matrix that form curved interfaces with the matrix grains. This second fraction thus serves as an internal reference, since the particles at the grain boundaries melt at the bulk melting temperature. Utilizing an averaging procedure for the fast scanning calorimetry measurements and combining conventional differential scanning- and fast scanning calorimetry with microstructure investigations, we found strong evidence for the observation of a heating-rate dependence of the melting transformation of the matrix-embedded nanoparticles. This observation gives rise to discuss the kinetics of melting in cases where the most potent nucleant for melting, the surface, is deactivated.