Effect of current density on distribution coefficient of solute at solid-liquid interface

When current passes through the solid-liquid interface, the growth rate of crystal, solid-liquid interface energy and radius of curvature at dendritic tip will change. Based on this fact, the theoretical relation between the distribution of solute at solid-liquid interface and current density was established, and the effect of current on the distribution coefficient of solute through effecting the rate of crystal growth, the solid-liquid interface energy and the radius of curvature at the dendritic tip was discussed. The results show that as the current density increases, the distribution coefficient of solute tends to rise in a whole, and when the former is larger than about 400 A/cm 2, the latter varies significantly.

非晶态镍基合金表面亚稳态蚀孔生长的动力学特征

用恒电位下的电流时－间记录法研究了非晶态ＮｉＣｒＦｅＳｉＢ合金在ＮａＣｌ溶液中的亚稳态蚀孔的生长动力学行为。恒电位下亚稳孔蚀电流与时间的关系为Ｉ－Ｉ０＝ｋ（ｔ－ｔ０）＾２，ｋ表征亚稳小孔的生长速度。大量亚稳态蚀孔的ｋ值服从对数正态分布，随电位升高，ｋ的平均值和标准差都增大。亚稳蚀孔的峰值电流在恒电位下也服从对数正态分布随电位升高而增大。文中提出一个亚稳态蚀孔生长的两阶段模型，解释了实验结果。