Nonparabolic nanoscale shift of phase boundaries in binary systems with restricted solubility
Nonparabolic nanoscale shift of phase boundaries in binary systems with restricted solubility
复制标题
溶解度有限的二元系统中相界的非抛物线纳米级位移
DOI：
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发表时间：
2004
期刊：
影响因子：
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通讯作者：
D. Beke
中科院分区：
文献类型：
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作者：
Z. Erdélyi;G. Katona;D. Beke
用计算机模拟的方法研究了扩散不对称性与扩散系数的成分依赖性之间的相互作用。和相分离趋势~化学效应！在有限溶解度的二元体系中溶解过程中界面移动的动力学。我们已经发现，在纳米尺度上，仅考虑扩散不对称性，化学尖锐界面的位移与时间的平方根不成比例，如从Fick定律所预期的那样，而是与tkc成比例，其中0.25，kc，1 ~偏离抛物线定律！在理想系统中，0.5<kc<1，但随着混合能（V）的增加，界面位移返回到抛物线定律（kc '0.5），并且在非常大的V值下，kc甚至可以小于0.5。这种效果是真实的“纳米效应”，因为溶解一定数量的层后~长时间或宏观极限！，界面移动返回到抛物线行为。它还说明，这些现象可以观察到实验以及。
Computer simulations were used to study the interplay of the diffusion asymmetry ~composition dependence of diffusion coefficient! and the phase-separation tendency ~chemical effect! in the kinetics of the interface shift during dissolution in a binary system with restricted solubility. We have found that—on nanoscale, taking into account only the diffusion asymmetry—the shift of the chemically sharp interface is not proportional to the square root of the time as would be expected from Fick’s laws but to t kc, where 0.25,k c,1 ~deviations from the parabolic law!. In ideal systems 0.5<kc<1, but with increasing mixing energy ( V) the interface shift returns to the parabolic law ( kc’0.5), and at very large V values k c can be even less than 0.5. This effect is a real ‘‘nanoeffect,’’ because after dissolving a certain number of layers ~long time or macroscopic limit!, the interface shift returns to the parabolic behavior. It is also illustrated that these phenomena can be observed experimentally as well.