Copper is in a passive state in a potential range of 50 mVH to about 300 mVH in contact with an aqueous electrolyte at neutral pH caused by the formation of a thin tarnishing layer consisting of copper(I)‐corrosion products. This layer inhibits more the anodic than the cathodic partial reaction of the corrosion process. The steep threshold in the transpassive range leads to the oxidation of copper and the formation of secondarily formed reaction layers.
In sulphate containing electrolytes voluminous reaction layers of crystalline non‐protective copper(I)‐oxide are formed. The manifestation of corrosion is general attack. In chloride containing electrolytes a two‐fold reaction layer is formed, copper(I)‐chloride underneath copper(I)‐oxide. This amorphous copper(I)‐oxide is formed via hydrolysis of copper(I)‐chloride and inhibits anodic metal dissolution. The only observed manifestation of corrosion is repassivating pitting.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.