The role of P in the anodic inhibition of an amorphous Co-20P alloy in acidic electrolytes

Journal Article · Sat Aug 01 04:00:00 EDT 1992 · Journal of the Electrochemical Society; (United States)

DOI:https://doi.org/10.1149/1.2221189· OSTI ID:7180310

Helfard, M A; Clayton, C R ^[1]; Diegle, R B; Sovenson, N R ^[2]

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1. State Univ. of New York, Stony Brook, NY (United States). Dept. of Materials Science and Engineering
2. Sandia National Labs., Albuquerque, NM (United States)

Anodic polarization of an amorphous Co-20P alloy in deaerated 0.2N H[sub 2]SO[sub 4] or 0.2N HCl shows alloy dissolution to be inhibited at potentials between approximately - 0.3 and 0.2 V (SCE), while pure crystalline Co dissolves readily and does not passivate at anodic potentials in either electrolyte. Analysis of Co-20P surfaces by x-ray photoelectron spectroscopy after anodic polarization reveals an enrichment of elemental P in the near-surface region, the presence of approximately a monolayer of hypophosphite and phosphate ions on the surface, and a virtual absence of oxidized cobalt species. Thus, the Co-20P alloy does not inhibit dissolution by the development of a three-dimensional cobalt oxide film. A chemical process that is controlled by the formation and surface retention of hypophosphite anions is proposed in this paper. An identical passivation mechanism has been previously observed with an amorphous Ni-20P alloy.

• Sponsoring Organization: NSF; National Science Foundation, Washington, DC (United States)
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 7180310
• Journal Information: Journal of the Electrochemical Society; (United States), Journal Name: Journal of the Electrochemical Society; (United States) Vol. 139:8; ISSN JESOAN; ISSN 0013-4651
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400400* -- Electrochemistry
AMORPHOUS STATE
ANODES
CHALCOGENIDES
CHLORINE COMPOUNDS
COBALT
COBALT COMPOUNDS
COBALT OXIDES
COBALT PHOSPHIDES
DEAERATORS
DISSOLUTION
ELECTRODES
ELECTROLYTES
ELECTROMAGNETIC RADIATION
ELECTRON SPECTROSCOPY
ELEMENTS
FILMS
HALOGEN COMPOUNDS
HYDROCHLORIC ACID
HYDROGEN COMPOUNDS
INHIBITION
INORGANIC ACIDS
IONIZING RADIATIONS
METALS
NICKEL COMPOUNDS
NICKEL PHOSPHIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PHOSPHIDES
PHOSPHORUS
PHOSPHORUS COMPOUNDS
PHOTOELECTRON SPECTROSCOPY
PNICTIDES
POTENTIALS
RADIATIONS
SPECTROSCOPY
SULFURIC ACID
SURFACE PROPERTIES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
X RADIATION