金属催化化学沉积反应的电化学本质研究

Electrochemical Essence of Metal Catalytic Activity for Electroless Deposition

摘要:

以次磷酸盐酸性化学沉积镍体系为对象，研究了基体对化学沉积反应具有催化活性的电化学本质。首先利用稳定电位的测量明确化学沉积镍反应中次磷酸盐氧化的决定性作用，并发现次磷酸盐的氧化反应也具有特征反应电位。基于先前研究得到的次磷酸盐阳极氧化机制，提出对化学沉积镍反应具有催化活性的金属需符合的条件是，在化学镀液中金属的电位高于次磷酸盐的氧化还原电位的同时，必须低于该金属在此特定镀液中的零电荷电位值。并选取5种具有代表性的金属进行了实验验证

Abstract:

Through the common-used acidic electroless nickel deposition system with hypophosphite, the electrochemical essence of catalytic activity of the substrate for electroless deposition was investigated. It is found that oxidation of hypophosphite is dominative for the electroless nickel deposition of the substrate by stable potential measurement, and there exists a typical reaction potential for the anodic oxidation of hypophosphite. On the basis of previously proposed oxidation model of hypophosphite, the necessary condition of the metal substrate with catalytic activity for electroless nickel deposition is put forward that the potential of the metal is not only higher than the redox potential of hypophosphite, but also lower than the metal’s potential of zero charge in the particular electrolyte. By examining the experimental results of five kinds of typical metal, the above hypothesis was proved.