DYNAMICAL NANOSRUCTURING OF NaCl PREMELTING PHASES
DOI:
https://doi.org/10.17308/kcmf.2018.20/636Keywords:
sodium chloride, premelting, melting point, fluctuation, nanocluster, dissipation states, coherent scattering region.Abstract
Complex investigation of NaCl premelting phases dynamical structuring have been carry out in different kinetic conditions. The transient states near the melting point are fluctuating, nonequilibrium processes, which are accompanied by dissipative states formation. Thermodynamic parameters of premelting transient states (Т'pre-m – temperature of the premelting beginning, T''pre-m – temperature of the premelting end, dTpre-m – temperature interval of premelting, DQpre-m – dissipation heat of premelting) are determined in different heating rates. Each heating rate has definite value of thermodynamic parameters. Frequency spectrum of dissipation heat at different kinetic conditions is a nonlinear Brownian noise or 1/f2-noise, which is indirectly indicated of dynamical reconstruction in premelting excited state.
The nanocluster parameters in NaCl premelting phases have been calculated by experimental thermodynamic data. Average cluster size in NaCl premelting phase is 10-15 nm. X-ray analysis of NaCl in premelting state is indicated of nonmonotonic peak intensity. Such diffraction peaks behavior connected with heat fluctuations in premelting. Size of coherent scattering region is in agreement with calculated parameters of nanoclaster premelting phases.
Thus, amplification of fluctuations has been occurred near critical point (Т'pre-m) in consequence of anharmonism of lattice vibrations. Increase of fluctuations reduced to dynamic formation of nanocluster structures (generation of dissipative structures or ordering through fluctuations).
ACKNOWLEDGMENTS
The research results were obtained using the equipment of the Center for Collective Use of Equipment Voronezh State University.
