Effect of Specimen Shape On Corrosion in the Atmosphere

It is well known that the corrosion rate of metals in the atmosphere varies with the pollution present. Industrial and marine locations are more corrosive than rural locations. It is axiomatic therefore that the corrosion rate increases with the amount of contamination actually coming in contact with the specimen. This is controlled not only by the degree of pollution present, but also by the shape and form of the specimen. The shape determines the amount of air-borne pollution which impinges on the specimen. As this increases or decreases the corrosion rate increases or decreases. While this seems obvious enough it has generally been overlooked in the published literature. The present paper calls attention to this fact and gives appropriate illustrations. One illustration compares plain and threaded bars, another compares wire and sheet specimens, and a third involves insect screen.