Atmospheric Corrosion of Cobalt

Cobalt atmospheric corrosion is discussed, ranging from nucleation of water to observed indoor corrosion rates. The air-exposed surfaces of Co are shown to be complex oxyhydroxides. Significant quantities of water are adsorbed on this surface. The initial stage of corrosion in a polluted environment is shown to be very heterogeneous. Corrosion kinetics for Co are linear and are exponentially dependent on relative humidity. The partial pressures of SO2, Cl2 and NH3 significantly influence Co corrosion while H2S, NO2 and O3 show little effect. corrodes in indoor environments at rates similar to Ni and follows log normal statistics over the field site population studied.38 refs.--AA