Technique for Estimating Atmospheric Corrosion Rate of Zinc in Coastal Areas

In coastal areas, sea-salt particles floating in the air above the ocean are blown toward by the wind and adhere to the surface of metals, severely corroding them. Japan is an island country and thus, salt damage is the most impotant factor affecting atmospheric corrosion. However, sea-salt-particle level decreases with increasing distance from the coast. Other factors such as temperature and precipitation also affect the corrosion rate. Therefore, it was difficult to determine the corrosion rates at each area. A method has been developed for estimating the atmospheric corrosion rate of zinc caused by airborne salinity. The method estimates the corrosion rate from easily available data such as temperature, humidity, precipitation, direction and velocity of wind, and distance from the coast. The accuracy of the method was ±30% compared with the results of field tests.