KINETICS IN NANOPARTICLE SYSTEMS

Nanoscale materials can be produced in many ways, including biogenic routes that utilize organic molecules, physical methods such as mechanical ball milling, chemical methods such as chemical vapor deposition (CVD), electrochemical methods, and sol-gel methods. Due to the many pathways, the mechanisms and kinetics of their formation are 

In the processing of nanoparticles, coarsening is common, and may be accompanied by phase transformation to the macroscopic stable structure. Here we will focus on the kinetics of phase transformations and crystal growth in nanocrystalline particles. We will show later that conventional kinetic models that are widely employed for analysis of macroscopic materials behavior may have to be modified prior to their application to nanomaterials. 

Brief review of kinetic models for macroscopic solids 

Introduction to the JMAK approach. Detailed description of the JMAK formal theory was given by Christian (1975). The basic assumptions of the theory are that the stable phase nucleates as infinitely small droplets these droplets are rigid, and grow independently the growing droplets can overlap and that the dimensions of the parent phase are essentially infinite. Then the volume fraction of transformation, for a number of nucleation-growth cases can be reduced to the general form of (Christian 1975) 

the parameters k and n can be evaluated with the so-called log-log plot of the experimental data obtained. 

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