Molecular dynamics studies of the size and temperature dependence of the kinetics of freezing of Fe nanoparticles

Journal Article · Fri Nov 15 00:00:00 EST 2013 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2013.09.008· OSTI ID:22274142

Zhao, Bo; Huang, Jinfan; Bartell, Lawrence S.

Molecular dynamics (MD) computer simulations have been carried out and a novel modified technique of Voronoi polyhedra has been performed to identify solid-like particles in a molten nanoparticle. This technique works quite well in analyzing the effects of particle size on nucleation rates of iron nanoparticles in the temperature range of 750–1160 K. Nanoparticles with 1436 and 2133 Fe atoms have been examined and the results are compared with those obtained earlier with Fe{sub 331} nanoparticles. Nucleation rates for freezing obtained from MD simulations for Fe{sub 2133} vary from 8.8×10{sup 34} m{sup 3}/s to 4.1×10{sup 35} m{sup 3}/s at over a temperature range from 1160 K to 900 K, Rates for. Fe{sub 1436} and Fe{sub 331} are somewhat higher. Nucleation rates increase as supercooling deepens until the viscosity of the liquid increases sharply enough to slow down the rate. Bt applying classical nucleation theory, the interfacial free energy between solid and liquid cab be estimated From this and other thermodynamic information can be derived a theoretical expression for the size-dependence of the heat of fusion of nanoparticles. Results agreed quite well with those observed in our MD observations. An earlier expression in the literature for this size-dependence was shown to be incorrect. The size dependence of melting point is discussed. - Graphical abstract: Critical nuclei of crystallization. Display Omitted - Highlights: • Solid state material synthesis. • Material structure. • Experimental study of nucleation in condensed materials. • Computation study of nucleation in condensed materials.

• OSTI ID: 22274142
• Journal Information: Journal of Solid State Chemistry, Vol. 207; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
77 NANOSCIENCE AND NANOTECHNOLOGY
COMPUTERIZED SIMULATION
CRYSTALLIZATION
FREE ENERGY
FREEZING
FUSION HEAT
KINETICS
LIQUIDS
MELTING POINTS
MOLECULAR DYNAMICS METHOD
NANOSTRUCTURES
NUCLEATION
PARTICLE SIZE
PARTICLES
SOLIDS
SYNTHESIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
VISCOSITY