Electrodeposition Preparation Of Zinc Metal Foam

Foam metal, as new functional materials with unique characteristics and structure, has a broad potential application in many fields such as impact energy absorber, silencer, filter, flame arrester, heater, heat exchanger, constructional materials, catalyst, catalyst carrier, porous electrode, electromagnetic shielding materials and electrode materials of secondary batteries. In virtue of the excellent three-dimensional reticulated structure, high porosity, high specific surface area, uniform quality and good activity, foam zinc is a potential substitute of zinc powder as a new kind of ideal material for electrode of zinc-air batteries, which has been widely used in many fields.Based on the review of considerable technical literatures and a series of experiments, the porous zinc foam was prepared by the processes of degreasing, roughening, conductive treatment and electro-deposition, using the polyurethane foam as substrate. The organic solvent degreasing and alkaline degreasing were combined as the degreasing process firstly, and then the roughening effects of KMnO4 and H2SO4 were studied. The result shows that the optimum roughening effect can be obtained by roughening for 5 min at 45℃, and the chemical deposits with good can adhesion to the polyurethane foam can be obtained on the framework of the polyurethane foam.Electro-deposition on polymer foam requires electrical conductivity of the initial polymer foam. Two methods were utilized in this work: firstly coating the polymer foam with electrically conductive slurry; secondarily immersing the foam into an electroless plating solution. The salt-based colloid palladium was used for the sensitization and activation of foam surface, and the optimum prescription and technological conditions of electroless plating were determined.Based on Hull Cell test, sulfate system was determined as the electroplating solution system by the comparison of three different systems. The experiments were carried out to explore the effects of solution composition (the concentration of ZnSO4) and the operation conditions (such as the interelectrode distance, the cathodic current density, the temperature and the pH value of electroplating solution) on the morphology of foam zinc and the current efficiency. The optimum factors of experiment conditions for the electro-deposition of foam zinc were determined in this work, and the foam zinc with three-dimensional reticulated structure, high porosity and lustrous appearance were produced.