The high-temperature oxidation of bulk nanocrystalline 304 stainless steel in air

• The oxidation resistance of BN-SS304 was enhanced during entire oxidation process.
• The diffusion rates of Mn0 and Cr0 in BN-SS304 were less than those in CP-SS304.
• The constant of parabolic rate of BN-SS304 was only about one fifth of CP-SS04.
• The less state density of valence electrons with low binding energies for BN-SS304.

The high-temperature oxidation of bulk nanocrystalline 304 stainless steel (BN-SS304) and its conventional polycrystalline counterpart (CP-SS304) in air at 900 °C for 24 h were studied by thermogravimetric analysis, X-ray photoelectron spectroscopy and scanning electron microscope. We studied the valence electron configurations of BN-SS304, CP-SS304 and their oxide scales by ultra-violet photoelectron spectroscopy. The high-temperature oxidation resistance of BN-SS304 was enhanced in both initial and isothermal oxidation, which was attributed to its larger work function and more chemical stability, its more chemically stable and compact oxide scale, its weaker O2 adsorption and diffusion, its weaker Cr and Mn atoms diffusions.