The effect of grain-boundary character on intergranular oxidation has been investigated in a Ni- 40 at.Fe polycrystalline alloy. A difference in the extent of intergranular oxidation between coincidence site lattice (hereafter denoted as CSL) boundaries and random boundaries was observed. In general, CSL boundaries were more immune to oxidation than random boundaries. Some specific CSL boundaries (∑3,11,19) were more resistant to oxidation than other CSL boundaries. This can be explained by a special feature of the grain-boundary energy for f.c.c. crystal structures. It is evident that in addition to the relative orientation relationship some geometrical parameters, such as grain-boundary inclination, are needed for the more precise engineering of grain boundaries to control intergranular oxidation.
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