Dissolution Behavior of Carbonyl Nickel Bead in Sulfuric Acid solution

The dissolution rates of common carbonyl nickel beads (CC) and high sulfur carbonyl nickel beads (HS) in sulfuric acid solution were compared by acid digestion method. The free corrosion potentials and free corrosion current densities of the two kinds of carbonyl nickel beads were also determined by electrochemical workstation. Microscopic corrosion morphology of the bead surfaces was observed by field emission scanning electron microscope. The corrosion products on the surfaces were analyzed by energy dispersive spectroscopy (EDS). The results show that the high sulfur carbonyl nickel bead was more easily soluble than the common carbonyl nickel bead in sulfuric acid solution, the corrosion potential of the former was more negative and its corrosion current density was higher. There were significant corrosion pits on the surface of the high sulfur carbonyl nickel bead after corrosion. The sulfur element in high sulfur carbonyl nickel bead formed sulfide on its surface, which promoted the dissolution of the high sulfur carbonyl nickel bead. When nickel sulfide additive was added in the dissolution of common carbonyl nickel beads in sulfuric acid solution, the dissolution rate could be improved.