Some Aspects of the Atmospheric Corrosion of Copper in the Presence of Sodium Chloride

The effect of NaCl in combination with and on the atmospheric corrosion of copper was investigated. Corrosion products formed after 4 weeks exposure were characterized qualitatively by X‐ray diffraction and quantitatively by gravimetry and ion chromatography of leaching solutions. Studies of deposition and consumption were preformed using on‐line gas analysis. Large amounts of cuprite formed in all environments at 70 and 90% relative humidity. The corrosive effect of salt was strong in pure humid air and in air containing or . Corrosion rate was correlated to the amount of chloride applied to the surface and to humidity. In an atmosphere containing a combination of and at 90% relative humidity, corrosion was rapid in the absence of NaCl. In this case, small additions of NaCl resulted in a marked decrease in corrosion rate. In the absence of , tenorite (CuO), nantokite (CuCl), clinoatacamite , and malachite were identified. In the presence of , brochantite , soluble sulfate, and an unknown phase occurred, while no tenorite or malachite was formed. The combination of and resulted in the formation of antlerite and as well.