Dissertation > Industrial Technology > Chemical Industry > Electrochemical industries > Electroplating industry

A Preliminary Study on the Electrochemical Oscillation of Zinc Powder Process by Electrodeposition

Author DuXiuFeng
Tutor YangChangChun
School Zhengzhou University
Course Physical and chemical
Keywords zinc electrode the electrochemical oscillation affecting factors
Type Master's thesis
Year 2013
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The electrochemical oscillation is phenomenon in time and space when a parameter in the system of electrode reaction is far from the equilibrium, which is composed of electrode and electrolyte multiphase oscillation. These processes have electrochemical oscillation occurs that the electric dissolution and the electrodeposition process of copper, aluminum, lead, gold, cobalt, iron, zinc and other metal and metal alloy, as well as the atalytic processesthe of small organic molecules and the electrochemical processes in the organisms. The study of electrochemical oscillations of anodic dissolution of the most and in-depth, has formed a preliminary mechanism and models.The process of electrodeposition of zinc powder, as a necessary step to zinc electrode of sedimentary type, the research for the electrochemical oscillation behavior on it has major significance for industrial production. In this article, the main mechanism of the electrochemical oscillation phenomenon of electrodeposited zinc powder is made a preliminary inference, and the experiments have designed to explore the reasons caused the electrochemical oscillation phenomenon and the Influence factors on the impact of the constant current potentiometric concussion, such as current density, the kind of zinc, the area ratio of anode to cathode, temperature, the electrolyte composition and other factors.The electrochemical oscillation of cell voltage in the electrodeposition of zinc is two mainly influence factors that the process of the surface of the zinc electrode and the processes of ions transmission in the electrolyte. The zinc electrode anodic dissolution process is often accompanied by the occurrence of the phenomenon of passivation and oxygen evolution. The higher current density, the passivation of zinc electrode and oxygen evolution degree is more deep, the electrochemical oscillation phenomenon is more obvious. The oxygen of precipitation is not only result the electrolyte in forced convection and accelerates mass transfer, but also causes the generated passivation film to mechanical damage. It is the main cause of electrochemical oscillation produced by zinc electrode potential that the periodic oxygen evolution and the periodic formation and destruction of Passivation membrane. Temperature impacts on the stability and the mass transfer rate of the intermediates produce from the dissolution process. In addition, the cavitation on the surface of zinc electrode has changed the actual current density, so that deepen the degree of electrochemical oscillation in a certain extent.The factors such as current density, the kind of zinc, the area ratio of anode to cathode, temperature, the electrolyte composition are the influence from the condition of zinc electrode surface and the electrolyte mass transfer of these two aspects to the influence of electrochemical oscillation when the electrochemical deposition of zinc powder. The interaction of several factors, make the two aspecrs mutual coupling each other, so that these two aspects lead to the differet of produce an electrochemical shock induction period, amplitude, life, frequency,even the types of oscillation.

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