Oxidation Resistance

(resistance to sealing), the ability of metallic materials to resist chemical degradation of the surface caused by the action of air or other gaseous mediums at high temperatures.

The oxidation resistance of a metal or alloy in an oxidizing atmosphere is determined by the properties of the oxide layer—scale—that forms on the surface of the metal and inhibits the diffusion of gas into the metal, thus reducing the development of gaseous corrosion. The quantitative characteristics of oxidation resistance are the increase in the weight of the sample being studied (because of oxygen uptake by the metal), or the weight loss after removal of the scale from the surface of the sample, relative to a unit surface and the duration of the experiment. The condition of the surface of the sample or part is simultaneously taken into account; it may differ qualitatively even though its quantitative characteristics may be the same. Along with heat resistance, oxidation resistance is a basic criterion of the suitability of a given material for high-temperature service.