Corrosion testing continued galvanic

Two frequent alternatives to ASTM B 117 testing used in the evaluation of general and galvanic corrosion performance have been (1) alternate immersion testing (30 s immersion in 3 % NaCl followed by 2 min in air [4,5,7], or (2) continuous immersion in 3 or 5 % NaCl for a period of three... 

G 44 can be used for both stressed and unstressed specimens. Historically, it has been used for stress corrosion cracking testing, but often is used for other forms of corrosion, such as uniform, pitting, intergranular, and galvanic. It uses a 1-h cycle that includes a 10-min period in a aqueous solution of 3.5 % sodium chloride (NaCl) followed by a 50-min period out of the solution, during which the specimens are allowed to dry. This 1-h cycle is continued 24 h/day for the total number of days for the particular alloy being tested. 

Hinton et al. (1988) have immersed a copper-mild steel galvanic couple in tap water containing 200 ppm CeCb for 20 hours until the Ce oxide film was observed on the copper cathode. The couple was then removed, washed and immersed into tap water without any CeCb. In this instance the galvanic current remained virtually unchanged from the equilibrium value which was observed before the switch in test solutions. This indicates that the R oxide films, which form on cathodic areas, continue to inhibit galvanic corrosion even after the removal of the inhibiting cations from solution. 

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