Microstructure and melting behavior of tin nanoparticles embedded in alumina matrix processed by ball milling

Tin dioxide and aluminum powders were ball milled for different time periods. Sn particles embedded in Al2O3 matrix formed through a displacement reaction after ball milling. However, SnO2 cores remain within some larger particles, while in smaller particles pure Sn cores exist. The embedded Sn particle size was found to increase with the milling time, which is attributed to the thermal effect provided by the exothermic displacement reaction during prolonged milling. Melting point depressions were observed. The melting temperatures of the Sn particles scale linearly with the inverse particle sizes. The extent of melting point depressions is observed to be slightly larger than those in the literature. This is ascribed to the simultaneous presence of Sn-Al2O3 and Sn-SnO2 interfaces.