2016/05/25 by D.M. Herlach, Diter M. Herlach, Thomas Palberg +3 · 49 citations
Chemistry · Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Chemical physics #Chemistry #Classical nucleation theory #Composite material #Crystal (programming language) #Crystallization #Crystallization and Solubility Studies #Crystallography #Gibbs free energy #Material Dynamics and Properties #Materials science #Metastability #Nucleation #Organic chemistry #Phase (matter) #Physics #Supercooling #Surface energy #Thermodynamics #cond-mat.mtrl-sci #nanoparticles nucleation surface interactions
paper · pdf · doi:10.1063/1.4963684
published in The Journal of Chemical Physics 145(21), 211703 (American Institute of Physics) · Invited review submitted for a special issue of J. Chem. Phys. "Overview Articles - Special Topic: Nucleation: New Concepts and Discoveries on the physics of nucleation". Submitted 2016 May 10. 61 pages 189 References 25 Figures. Abstract above is slightly shoretened to match ArXive rules v2 - added reprint permissions to all figures
arxiv created 2016/05/25 · openalex publication_date 2016/09/30 · arxiv updated 2016/11/03 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
Crystallization is one of the most important phase transformations of first order. In the case of metals and alloys, the liquid phase is the parent phase of materials production. The conditions of the crystallization process control the as-solidified material in its chemical and physical properties. Nucleation initiates the crystallization of a liquid. It selects the crystallographic phase, stable or meta-stable. Its detailed knowledge is therefore mandatory for the design of materials. We present techniques of containerless processing for nucleation studies of metals and alloys. Experimental results demonstrate the power of these methods not only for crystal nucleation of stable solids but in particular also for investigations of crystal nucleation of metastable solids at extreme undercooling. This concerns the physical nature of heterogeneous versus homogeneous nucleation and nucleation of phases nucleated under non-equilibrium conditions. The results are analyzed within classical nucleation theory that defines the activation energy of homogeneous nucleation in terms of the interfacial energy and the difference of Gibbs free energies of solid and liquid. The interfacial energy acts as barrier for the nucleation process. Its experimental determination is difficult in the case of metals. In the second part of this work we therefore explore the potential of colloidal suspensions as model systems for the crystallization process. The nucleation process of colloids is observed in situ by optical observation and ultra-small angle X-ray diffraction using high intensity synchrotron radiation. It allows an unambiguous discrimination of homogeneous and heterogeneous nucleation as well as the determination of the interfacial free energy of the solid-liquid interface. Our results are used to construct Turnbull plots of colloids, which are discussed in relation to Turnbull plots of metals and support the hypothesis that colloids are useful model systems to investigate crystal nucleation.