有机添加剂对碱性条件下电镀铋的影响

摘要

The electrodeposition of bismuth was studied by electrochemical techniques with the presence of the organic agents. The results show that, in the test for cyclic voltammetry, the electrodeposition of bismuth is a diffusion­ irreversible­controlled process associated with a typical nucleation process. With simultaneously addition of amino tris(methylene phosphonic acid) organic agents in alkalinity solution, the redox potential of bismuth is shifted to more negative potentials. In this case, the current transients reveal an progressive nucleation with a typical three­dimensional (3D) growth mechanism. The diffusion coefficients are obtained, respectively, approximately 1.17×10−5 and 1.55×10−5 cm2/s from the cyclic voltammetry and the chronoamperometry. Under the experimental conditions of this work, both of the patterns can be used for describing the electrodeposition of bismuth with the presence of organic agents in alkalinity solutions. In addition, the addition of amino tris(methylene phosphonic acid) refines grains in coating and the surface of coating becomes more even and compact.%　　利用电化学技术研究有机添加剂存在的碱性环境下铋的电沉积行为。结果表明：在循环伏安法试验中，铋的成核是一个扩散非可逆控制的电沉积过程，有机添加剂的存在使铋的沉积电位明显负移；在计时电流法试验中，铋的电沉积是一个典型三维连续成核过程。利用循环伏安法和计时电流法可以计算出非常接近的扩散系数，分别为1.17×10−5和1.55×10−5 cm2/s，说明这两种方法可用于有机添加剂电沉积铋的动力学计算研究。此外，氨基三亚甲基膦酸的加入细化了镀层晶粒，使镀层表面更加平整和致密。