Pulse Electrodeposition Preparation Of Ti-based Lead Composite Electrode Materials And Performance Research

At present, the lead alloys anode materials are widely used as insoluble anodes in the zinc electrowinning industry. However, there are universally have some disadvantages, for example, high potential of oxygen evolution, high cell voltage, low current efficiency and mechanical strength.In order to solve the problem of this kind of anode materials, in this paper, the experiments choose titanium sheet as the substrate, adding the WC powder and PANI powder into plating solution and using the method of pulse electroplating to prepare the new type of Ti/Pb-WC-PANI composite electrodes.In this paper, Ti/Pb-WC-PANI composite electrodes by pulse current were studied. The effects of process conditions and density of solid particles on the properties of composite electrodes were studied through condition experiments and the technology of composite electroplating was optimized. The optimal process conditions are as follows:PANI15g/l, WC30g/l, pulse width 0.3ms, cycle time 1.5ms, average current density 3 A-dm"2, bath temperature 25℃.In these conditions, kinetic parameters for oxygen evolution of composite electrodes were obtained as follow:a= 0.844, b= 0.274, i0=8.32×10-4.The electrocatalytic properties(such as oxygen overpotential, electrocatalytic activity, corrosion resistance and conductivity) of anode materials which are PC Ti/Pb-WC-PANI composite electrodes, DC Ti/Pb-WC-PANI composite electrodes, pure lead electrodes and lead alloys have been studied by linear sweep voltammograms, Cyclic voltammograms, Tafel polt and EIS. They show the electrocatalytic properties of PC Ti/Pb-WC-PANI composite electrodes are best.The morphology, surface composition and crystal phase were characterized by means of scanning electron microscopy, X-ray diffraction and infrared spectral analysis. The analysis results of SEM showed that the pure lead electrode's crystal cell were gibbous and made up of the particles. There were crack between the crystal cells. The DC Ti/Pb-WC-PANI composite electrode was compact and uniform. No crack between the crystal cells. The layer have clear crystal's boundary. A compact and uniform layer of Ti/Pb-WC-PANI was obtained at the pulse current. The crystal cells are polyhedron. Infrared spectral analysis shows that, compared with infrared absorption spectrum of the polyaniline, the Ti/Pb-WC-PANI composite electrodes have characteristic peak of polyaniline. So the polyaniline powders were deposited on titanium with lead. The phase analysis of Ti/Pb-WC-PANI composite electrode by XRD shows that lead and WC exist in the coatings, and the composite electrodes were crystalline structure as deposite. The XRD pattern of composite electrodes didn't showed the diffraction peaks of polyaniline. Compared with the diffraction peaks of pure lead electrode, the peaks intensities of the Ti/Pb-WC-PANIcomposite electrodes became less intense. The peaks intensities of PC Ti/Pb-WC-PANI composite electrodes were weaker than DC Ti/Pb-WC-PANI composite electrodes.Finally, The PC Ti/Pb-WC-PANI composite electrodes which were prepared at optimum condition were used in zinc electrowinning. The indexs of composite coatings such as cell voltage, current efficiency and intensifying lifetime are superior to lead alloy.