The Crevice Corrosion Behaviors and the Repassivation Characteristics of Ni and Ni(15, 30 percent)Cr Alloys

摘要

Characteristics of crevice corrosion on pure Ni and Ni-(15, 30 percent)Cr alloys were investigated, using the specially designed crevice cell and the micro Luggin capillary in IN H_2SO_4 solution with and without chloride ion. The potential profiles inside the crevice and the cell currents were measured with the variation of alloying element, Cr, applied potential, chloride ion concentration and immersion time. In order to examine repassivation characteristics, the abrading electrode measurements were performed. Experimental results showed that the repassivation kinetics of pure Ni and Ni-(15, 30 percent)Cr alloys after the passive film breakdown can be described as i = At~(-n) where n is the repassivation rate parameter. An attempt was made to establish the relationship between the occurrence of crevice corrosion and the repassivation rate parameter, n.