Dry corrosion of metals - Study methods

Dry corrosion is the degradation of a material in a chemically reactive environment under the effect of high temperature, and possibly mechanical stress.

It generally concerns advanced technological fields where the consequences of failures have a particularly high financial, environmental or human cost: thermal machines for transport (land, sea, air), energy conversion, nuclear industry, chemical industry (organic, mineral), metallurgy...

The specifications for the metallic materials used in these fields are increasingly demanding. Operating temperatures are being increased to boost efficiency. Cost reduction and environmental concerns are driving the choice of the right material, with the smallest possible thickness. Last but not least, safety requirements call for guaranteed service life under operating conditions, whether in terms of creep, microstructural stability or high-temperature oxidation.

There is therefore a strong demand for quantified knowledge of the behavior of materials subjected to dry corrosion. This demand is expressed in terms of reaction rates, limit temperatures for use, forbidden atmospheres, thermal cycling conditions or mechanical stresses in service.

The analysis of dry corrosion phenomena is of a multidisciplinary nature, requiring knowledge of metallurgy, surface science, thermodynamics and chemical kinetics, solid state chemistry and physics.

The first section of this article presents the phenomenon of dry corrosion and its specific features: distinction from aqueous corrosion, temperatures and atmospheres encountered, industrial fields concerned. The second section proposes a study approach, from the implementation of thermogravimetric monitoring experiments to the chemical, morphological and mechanical characterization of the corrosion layer and its interface with the metal.