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本文主要用恒电势法研究了钼晶核的形成和长大的动力学规律及其对电镀的影响。实验证明,在所选盐系、温度及浓度范围内,阴极反应开始阶段的控制步骤是半球形晶核的形成及其在扩散控制下的长大。适当控制影响这一步骤的因素,可以改善镀层质量。增大超电势将使晶核密度迅速增大,有利于获得结晶细致、光滑致密的镀层。在恒电势下,升高温度将使晶核密度增大,对改善镀层有利;而在恒电流下,升高温度则极化减小,晶核密度变小,对电镀不利。无论在恒电势或恒电流下,增大浓度都会使晶核密度变小,晶粒变粗,对电镀不利。
In this paper, the kinetic rules of the formation and growth of molybdenum nuclei and their effects on electroplating were studied by potentiostatic method. Experiments show that in the selected salt system, temperature and concentration range, the control step in the initial stage of cathode reaction is the formation of hemispherical nuclei and their growth under diffusion control. Proper control of the factors that affect this step can improve the quality of the coating. Increasing the overpotential will rapidly increase the density of the nuclei, which is conducive to obtaining the crystal with fine, smooth and dense coating. At a constant potential, increasing the temperature will increase the density of the nuclei, which is beneficial to the improvement of the coating. However, under the constant current, the increase of the temperature decreases the polarization and the density of the nuclei becomes smaller, which is unfavorable to the plating. Regardless of the constant potential or constant current, increasing the concentration will make the nucleus density becomes smaller, the grains become thicker, which is unfavorable to plating.