On the meaning of the impingement parameter in kinetic equations for nucleation and growth reactions
On the meaning of the impingement parameter in kinetic equations for nucleation and growth reactions
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DOI：
10.1023/a:1017974517877
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发表时间：
2001-09
影响因子：
4.5
通讯作者：
M. Starink
中科院分区：
文献类型：
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作者：
M. Starink
如果满足某些前提条件，Johnson-Mehl-Avrami-Kolmogorov (JMAK) 动力学方程对于线性生长的成核和生长反应来说是完全准确的，并且至少对于抛物线生长的成核和生长反应是一个很好的近似。这些前提条件包括随机分布的产物相、各向同性生长和恒定平衡状态。导致偏离这些先决条件的机制包括：毛细管效应、空位湮灭、各向异性生长造成的阻塞。结果表明，偏差会导致整体变换的修改，这可以通过单个方程很好地近似：其中 α 是变换的分数，ηii 是冲击参数，ns 和 k(T) 是取决于生长几何形状和生长速率的参数。讨论了影响冲击参数的因素。
If certain preconditions are met, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) kinetic equation is exactly accurate for nucleation and growth reactions with linear growth and is, at least, a good approximation for nucleation and growth reactions with parabolic growth. These preconditions include randomly distributed product phases, isotropic growth and constant equilibrium state. Mechanisms causing deviations from these preconditions include: capillarity effect, vacancy annihilation, blocking due to anisotropic growth. It is shown that deviations lead to a modification of the overall transformation, which can be approximated well by a single equation:where α is the fraction transformed, ηiis the impingement parameter,nsandk(T)are parameters that depend on growth geometry and growth rate. The factors which influence the impingement parameter are discussed.