Localized Corrosion of Aluminum: Blister Formation as a Precursor of Pitting

Abstract

Blisters have been observed in the oxide film of aluminum in aqueous chloride solutions. They can be initiated by short duration (⪝ 1 msec), low voltage pulses. Such blisters grow only if the steady‐state potential of the specimen is above the pitting potential. The growth proceeds laterally along the oxide‐metal interface. Upon breaking, as a result of gas pressure from within, pitting corrosion begins. Thus, in this instance, blisters are experimentally demonstrable precursors of pits.

EIS characterization of tantalum and niobium oxide films based on a modification of the point defect model

“…As was mentioned above, the formation of molecular H 2 is a plausible explanation occurring during the passive state of Ta 2 O 5 and Nb 2 O 5 films. Also, it can be suggested that this phenomenon could be responsible of the breakdown of passive films as has been reported in the literature [1,2]. In the present work, we are able to predict the blistering damage of the oxide films favored in solutions with high pH.…”

“…The breakdown of oxide films may be promoted by the formation of molecular hydrogen at the metal-film interface, when a critical condition of pressure is reached. Experimental evidence for this phenomenon has been reported in the literature for different electrochemical interfaces [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17].…”

“…The blistering damage is an important occurrence observed on passive oxides, because it has been experimentally reported as one of the possible reasons provoking the breakdown of the films, which have been related to localized corrosion pitting [1,2]. The blistering damage has been observed in metals such as aluminum, zirconium, niobium in aqueous solutions; it has also been suggested that it may occur in the presence or absence of halide ions [1,2]. The breakdown of oxide films may be promoted by the formation of molecular hydrogen at the metal-film interface, when a critical condition of pressure is reached.…”

Defects producing formation of micro-cracks in aluminum during electrochemical charging with hydrogen

“…Surface bubbles are pressurized by the hydrogen gas and extra material for the surface bubble wall is provided by the low-density porous hydrous oxide. The compact barrier layer cannot be penetrated by the gas molecules and hence, a high pressure of gas can develop within the surface bubbles (blisters) [21,22]. Determination of hydrogen fugacities in environmental cells by TEM was carried out by Bond et al [23].…”

Chloride Ion Interactions with Oxide-Covered Aluminum Leading to Pitting Corrosion: A Review

“…Blister formation and rupture was first reported on Al by Bargeron and Givens 120,121 and subsequently by others. 122,123 Pit caps were observed for Al earlier.…”