Professor, C. N. R. S. U. A. 216, Groupe Corrosion, Universite, Paris, Paris,
Pages: 10 Published: Jan 1988
Simulation tests for indoor and outdoor atmospheric corrosion appear essential to reliably predict the behavior of designs and materials in operating environments. Chamber tests are preferentially conducted for indoor corrosion. Some results are given concerning the sulfidation of copper and silver by H2S (hydrogen sulfide) in the presence of additives such as NO2 (nitrogen dioxide) or Cl2 (chlorine molecule). It is shown that chemical reactions between gases are responsible for the acceleration of the rate of sulfidation of metals. Comparison with onsite measurements shows that several classes of test severities must be defined. In studying outdoor atmospheric corrosion, attention is presently focused on the use of electrochemical sensors, which allow the determination of times of wetness and corrosion rates. Chamber tests may be used in some special cases. An example is given for the behavior of metallic materials exposed to corrosion under storage conditions. The combination of chamber and electrochemical tests has led to some understanding of the mechanism of formation and spread of corrosion products for an Fe-Ni alloy. The alloy has a behavior intermediate between that of an active (iron-like) material and a self-passivated (stainless steel-like) one, depending on the aeration conditions of the surface.
corrosion, atmosphere, hydrogen sulfide, chlorine, nitrogen dioxide, storage
Paper ID: STP25998S