Effect of grain boundary characteristics on the oxidation behavior of ferritic stainless steel

The effect of grain boundary characteristics on the oxidation of ferritic stainless steel was investigated using XRD, SEM, energy dispersive spectroscopy, and electron backscattered diffraction. Oxide crystals at special grain boundaries were compared with that of random boundaries. The spinel type oxide grew along the grain boundaries whereas both spinel and chromia grew at the grain interiors. Oxidation rate at special boundaries was slower than random boundaries. The resistance to oxidation of special boundaries is influenced by their angular deviation from the ideal coincidence site lattice (CSL) misorientation. The special boundaries near ideal CSL misorientation are more resistant to oxidation.

► Oxidation behavior at grain boundaries of ferritic stainless steel was investigated.
► Oxidation behavior at CSL boundaries was compared with that of random boundaries.
► Coarse oxide forms at random boundaries and CSL boundaries are oxidation resistant.
► CSL boundaries near ideal CSL misorientation are more resistant to oxidation.