Environmental Engineering Reference
In-Depth Information
Figure 6.5
Transition from internal to external oxidation in Ag-In alloys at 883 K
[15].
transition occurred at
N
(O)
In
0.15, respectively. The retardation
of internal oxidation in mechanically polished specimens has been attributed to
increased outward solute diffusivity along short circuit paths in the deformed
layer or decreased oxygen solubility due to excessive deformation of the surface
layer.
The internal oxidation behavior of various alloy systems, such as Cu-Be, Ni-
Cr, Fe-Cr, and Fe-Si, Nb-Zr, has been discussed at length by Birks and Meier
[16].
0.12 and
N
(O)
In
6.3.2 Catastrophic Oxidation
Until now, the formation of only solid oxide scale on metals and alloys has been
considered. In some cases, however, liquid oxide phases may also form as a part
of the reaction product. This may arise under the following two situations:
1.
If metals or alloys are exposed to the vapor of a low-melting oxide during
oxidation, or
2.
During oxidation of some alloys with an alloying element which itself forms
a low-melting oxide or which may form a low-melting eutectic of oxide
mixtures.
