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Structure and composition of thick tarnish films on alpha-phase copper alloys

Journal Article · · Corrosion; (United States)

Electron microprobe analysis, X-ray diffraction, and metallographic studies have been carried out on thick tarnish films formed on a series of alpha-phase Cu-Zn, Cu-Al, and Cu-Ni alloys by exposure to an ammoniacal solution. The results established that the tarnish films consist of an inner layer of Cu/sub 2/O and an outer layer of CuO, the latter being formed after long exposures. The microprobe data indicated that both oxides are essentially depleted with respect to the alloying elements, and appear to contain less copper than the stoichiometric values. These observations are consistent with the view that the Cu/sub 2/O is formed by a dissolution-reprecipitation mechanism; however, the mechanism of CuO formation is not yet understood.

Research Organization:
Univ. of Illinois, Urbana
OSTI ID:
7087733
Journal Information:
Corrosion; (United States), Journal Name: Corrosion; (United States) Vol. 32:6; ISSN CORRA
Country of Publication:
United States
Language:
English