Modification of ASTM B117 Salt Spray Corrosion Test and Its Correlation to Field Measurements of Silver Corrosion

Laboratory salt spray testing has been used for many years to accelerate natural atmospheric exposures with limited success. The corrosion of silver represents a stark example of the failings of such testing. In virtually any field environment, silver corrodes measurably in a month, but after 4 months in a standard salt spray test, no corrosion of silver is observed. The present work is concerned with the modification of the conventional salt spray corrosion test and its correlation to field measurements of silver. Two subsystems were designed and constructed to modify a conventional salt spray chamber. One subsystem consisted of ultraviolet A (UVA) lamps mounted on a movable rack, which allows them to be positioned to achieve the desired UVA light intensity. The other subsystem consisted of an ozone system based on a commercial ozone generator and a distribution manifold that allowed a uniform concentration of ozone to be maintained throughout the chamber. As constructed, the system can produce ...