Artificial Corrosion of Cu-Alloys. A Contribution to Understanding Microbial and Nonmicrobial Sulfide Corrosion.

摘要

Cu-10Ni wafers were corroded abiotically in synthetic seawater solutions containing various concentrations of H+, dissolved O2, and dissolved sulfide. The samples were not disturbed during the corrosion process by stirring or monitoring of the solution chemistry. The Eh, pH, and the concentrations of dissolved O2 and sulfide in the initial and final solutions were measured. Upon removal, the corroded wafers were analyzed by SEM, EDX, XPS, and electron microprobe. These analyses revealed the presence of chalcocite, paratoamite, cuprite, aragonite, and possible djurleite and digenite on the surfaces of the wafers. Adherence of the corrosion films varied with solution chemistry from those that were nonadherent to those showing good adherence. Copper and nickel behaved very differently during the experiments. The data suggest a model for the abiotic corrosion process that involves rapid scavenging of dissolved sulfide by copper to form an amorphous or cryptocystalline Cu-S minerals. The Cu-S minerals initially formed under reducing conditions existed even after the solutions become quite oxidizing.