Study on Corrosion Process of Lead Alloy Anode in Plating Solution of Tin Free Steel

Abstract

Plating solution of tin free steel (TFS) composes of Cr ions and F ions, which have a characteristic of strong corrosion. The weight loss/gain of the specimens immersed in the test solution was measured by using the electro-balance, to evaluate the erosion of the lead alloy in the corrosive solutions. The results show that lead alloy anode is eroded obviously by F- ions solution, and corrosion rates are constant throughout the examined time. The F- ions concentration have an insignificantly effect on corrosion rate. Corrosion product of anode materials in Cr6+ ions solution is partly deposited on anode materials surface, others might be dissolved into plating solution. This is leading to weight of anode materials remaining almost constant. But the weight of lead alloy anode firstly increases and decreases, then increases using the mixed solution of F- ions and Cr6+ ions as corrosive solution. Corrosion structure variation of lead alloy anode is investigated by means of X-ray diffraction (XRD). XRD results indicate that corrosion product structure is different using different ions solution as corrosive solution.