Corrosion behavior of tantalum and niobium in hydrobromic acid solutions (II) on passive films and hydrogen absorption

Journal Article · Sat Jul 01 00:00:00 EDT 1989 · Corrosion (Houston); (USA)

OSTI ID:6910234

Uebara, I; Sakai, T; Ishikawa, H; Takenaka, H ^[1]

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1. Government Industrial Research Institute, Osaka Midorigaoka, 1-8-31, Ikeda-shi, Osaka 563 (JP)

The authors report the corrosion behavior of tantalum (Ta) and niobium (Nb) in hydrobromic acid solutions studied with respect to their surface states and hydrizing by scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), a hydrogen determinator, and x-ray diffraction (XRD). The test specimens were immersed in a 47 wt% HBr solution bubbled with hydrogen and in another that contained 0.05 mol/dm{sup 3} of bromine at 25 and 100{degrees}C for 15, 30, and 45 days. On Ta under every condition and Nb at 25{degrees}C, the surface films consisting of their pentoxides thickened with increasing immersion time and exhibited no significant change in appearance or hydrogen content. However, fine pits less than 5{mu} in diameter were formed on Nb specimens in both the solutions at 100{degrees}C at the early stage of immersion. In the solution with hydrogen, the pitting extended over the specimen surfaces with increasing immersion time, and developed into general corrosion after 45 days. Progress of pitting was terminated in 15 days in the solution with bromine.

• OSTI ID: 6910234
• Journal Information: Corrosion (Houston); (USA), Vol. 45:7; ISSN 0010-9312
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
HYDROBROMIC ACID
CORROSIVE EFFECTS
NIOBIUM
PITTING CORROSION
SURFACES
HYDROGEN EMBRITTLEMENT
TANTALUM
OXIDES
PHOTOELECTRON SPECTROSCOPY
SCANNING ELECTRON MICROSCOPY
SOLUTIONS
THIN FILMS
X-RAY DIFFRACTION
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
CORROSION
DIFFRACTION
DISPERSIONS
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
EMBRITTLEMENT
FILMS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
METALS
MICROSCOPY
MIXTURES
OXYGEN COMPOUNDS
SCATTERING
SPECTROSCOPY
TRANSITION ELEMENTS
360205* - Ceramics
Cermets
& Refractories- Corrosion & Erosion
360202 - Ceramics
Cermets
& Refractories- Structure & Phase Studies
400101 - Activation
Nuclear Reaction
Radiometric & Radiochemical Procedures