5.6.2.3 Corrosion
by (Hot) Gasess
All oxide materials are
resistant to corrosion in air and oxidising atmospheres up
to temperatures close to their melting point.
At temperatures above 1,200°C, all non-oxide
materials react with oxygen. Many non-oxide materials –
SiCs in particular – develop thick protective layers
of silicon dioxide when oxidation begins, and this protects
them from further oxidation. Corrosion increases significantly
at temperatures above 1,420°C.
The corrosive reaction of ceramics to other
Gasess (Cl2, SO2, NOx etc.) is not well known.
In hydrothermal atmospheres certain quality classes of Al2O3
are resistant to Cl2, SO2 and NOx. Cordierite also meets the
demand for resistance to corrosion by hot Gasess in hydrothermal
atmospheres.
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