PITTING CORROSION OF ALUMINIUM IN CONTACT WITH STAINLESS STEEL

Technical Report · Tue May 01 04:00:00 EDT 1962

OSTI ID:4805847

Videm, K

Initiation and growth of corrosion pits on aluminum were studied under anodic polarization with a potentiostatic and galvanostatic technique on freely corroding aluminum and on coupons specially made for measuring the current flowing between aluminum and stainless steel in electrical contact. The isrst step in the development of pitting was a local destruction of the protective oxide film. This lead to so-called micropits, which under proper conditions can develop fhrther into normal pits. The rate of initiation was found to increase rapidly when the corrosion potential exceeded a certain value. The rate of growth was affected by a series of variables and the cathode reaction mainly determined the area of growing pits. Electrical contact with stainless steel increased the corrosion potential of aluminum and in many cases from a value where the corrosion was harmless into a region where initiation and growth of pits were rapid. Pitting will not occur on aluminum coupled to stainless steel if the water is sufficiently pure. However, dissolved corrosion products given off from the aluminum can make water of initial high purity so corrosive that pitting attack results. (auth)

• Research Organization: Norway. Institutt for Atomenergi, Kjeller
• NSA Number: NSA-16-024121
• OSTI ID: 4805847
• Report Number(s): KR-18
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ALUMINUM
ALUMINUM OXIDES
ANODES
CORROSION
FILMS
IMPURITIES
METALS, CERAMICS, AND OTHER MATERIALS
POLARIZATION
STAINLESS STEELS
WATER