VARIATION OF THE INTERFACIAL ENERGY WITH GRAIN-SIZE IN NANOCRYSTALLINE MATERIALS

The transformation of an amorphous Ni-P alloy was investigated calorimetrically. In particular, the formation of the interfaces in nanocrystalline Ni-P samples with grain sizes ranging from a few nanometers to 60 nm was studied. A linear increase in the interfacial excess energy was found with increasing grain size on a nanometer scale. However, a rather small interfacial excess energy was obtained when the grain size was a few nanometers. The variation of interfacial excess energy with grain size was found to correlate with that of the interfacial excess volume derived from experimental results.