Melting-point kinetic aspect

Because of the importance of microstructure on dielectric and ferroelectric properties, the transformation pathway associated with conversion of the amorphous film into the crystalline state has been studied extensively. The basic mechanism involved is one of nucleation and growth, although the formation of intermediate phases that can impact the thermodynamic driving forces associated with the transformation frequently occurs. " Another key aspect of CSD films is that crystallization occurs well below the melting point of the materials. Therefore, compared to standard mixed-oxide processing of bulk materials, the thermodynamic driving forces associated with the transformation are much greater and the kinetics of mass transport are much less. 

Fused iron catalysts are composed of iron oxides (Fes04, FeO) and a small amount of promoters which are usually metal oxides with high melting points such as AI2O3, K2O, CaO, MgO and Si02 etc. The iron oxides must be reduced to metal state to have catalytic activity, but other oxides which act as promoters carmot be reduced. The activity and durability of catalysts are dependent upon the chemical composition, preparation method, reduction procedm-e and conditions. Thus the reduction is a crucial step in the manufacture and application of catalysts, and the performance and kinetics of reduction are important aspects in the study of catalysts. 

Flory outlined [3] that the definition of polycondensation is necessarily based on kinetic aspects and not on the structure of polycondensates, because numerous polycondensates can also be prepared by ROP which usually proceeds as chain-growth polymerization. Flory s definition of step-growth polymerization is limited to polycondensations and polyadditions in the melt or in solution, and does not include solid-state polycondensations. Hory s definition of step-growth polymerizations is based on point 1. 

---