7. High-temperature oxidation resistance

7.1 Oxidation in air

Oxidation in air is the most classic form of hot corrosion. The oxidation resistance of refractory steels and alloys results from the formation of an adherent, low-permeability oxide layer.

For the oxide layer to be protective, it is essential that oxygen cannot come into contact with the base metal. This condition is verified for a number of metals found in refractory steels and alloys, essentially :

• chromium, which creates a unique Cr ₂ O ₃ oxide;

• aluminum with Al ₂ O ₃ ;...