Thermal stability of Fe, Co, Ni metal nanoparticles

The thermal stability of metal nanoparticles is discussed in both melting thermodynamics and interface thermodynamics. Emphases are put on the size and shape dependence of melting temperature, critical size and vacancy-formation energy of both freestanding and embedded metal nanoparticles. The melting temperature depression and superheating phenomena for reported nanoparticle systems are explained. Critical sizes of Fe, Co, Ni metal nanocrystals that the crystals keep their crystallinity are calculated and the corresponding minimum melting temperatures predicted. The vacancy-formation energies of Fe, Co, Ni small particles are also calculated as a reference. Theoretical predictions are consistent with experimental results. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.