Corrosion testing continued laboratory methods

A similar method of test was used at the International Nickel Company s Corrosion Laboratory at North Carolina. The specimen discs are mounted on insulated vertical spindles and submerged in sea-water, which is supplied continuously to the tank in which the specimens are immersed. The maximum peripheral speed of the spinning disc is about 760cms , and the characteristic pattern of attack is shown in Fig. 19.3a. Studies of variation of depth of attack with velocity indicate that at low velocities (up to about 450 cm s ) alloys such as Admiralty brass, Cu-lONi and cupro-nickel alloys containing iron maintain their protective film with a consequent small and similar depth of attack for the diflferent alloys. At higher velocities the rate increases due to breakdown of the film. 

Testing procedures for cracked concrete are essentially the same as used for other laboratory specimens exposed to chloride solutions continuously or cyclically. Methods that can be used include polarization resistance, electrochemical impedance, and macrocell corrosion which were discussed above. Procedures for conducting these tests are described in Refs 27 and 28. 

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