Atmospheric Corrosion of Silver, Copper, and Nickel—Environmental Test

Abstract

The corrosion growth kinetics for Cu, Ni, and Ag in an air‐conditioned telephone office and a nonair‐conditioned telephone office basement have been obtained by measuring the film thicknesses on coupons exposed for various times. The film constituents and thicknesses on these materials were obtained by AES and cathodic reduction. Over a two year period, Ag tarnishes linearly and the major film constituents are sulfur and chlorine. Copper and nickel corrosion data have been fitted to parabolic growth rate kinetics and the film thicknesses have been extrapolated to 40 years. The major film constituents on Cu and Ni are oxygen, chlorine, and sulfur. The film constituents and thicknesses have also been obtained by exposing the same materials in the One Year environmental test. The constituents are similar to the films grown in the field. Acceleration factors for the One Year test for these materials have been derived by comparing film thicknesses to those developed in the field. It is concluded that the One Year test is a suitable test for Cu and Ni but not for Ag.