Study on the Influence of Sulfuric Acid Concentration on the Properties of the Electrodeposited Wick

Porous copper wick was prepared on copper surface by electrodeposition method. The effects of sulfuric acid solution with different concentrations on the morphology, thickness, porosity and stability of the wick were studied. The mechanism of copper electrode position was analyzed via cathodic polarization and chronoamperometry. The results show that with the increasing concentration of sulfuric acid, the amount of powder like wick structure, the thickness and porosity of wick increase gradually. The wick stability decreases continuously. Capillary performance first increases and then decreases. The wick prepared in 2.5 mol/L sulfuric acid solution displays the best capillary performance, and the shortest wetting time is 16 s. Cathodic polarization measurements show that the nucleation potential of copper shifts to positive slightly with the increase of sulfuric acid concentration, and the degree of the corresponding cathodic polarization decreases. The chronoamperometry results show that the diffusion coefficient of copper ions decreases with the increase of sulfuric acid concentration. The electrodeposition mechanism of copper is three-dimensional instantaneous nucleation and controlled by copper ion diffusion.