| High temperature oxidation and corrosion of metal are the key problems in in theirapplications, and have important effect in the development of the modern science andtechnology and engineering, which play important roles in high technology andindustrial areas’ developments especially in aviation, aerospace, energy, power,petroleum chemical industry. The special physical, chemical and mechanicalproperties of nano materials are subjected to wide attention in various fields. Thefurther study of the electronic structure of surface on the nano metallic materials is toguide the development of high temperature oxidation resistance, corrosion resistance.Bulk nanocrystalline304stainless steel and bulk nanocrystalline pure aluminumwere prepared by severe rolling technique, We characterized the surface electronicstructure of bulk nanocrystalline304stainless steel and conventional polycrystalline304stainless steel, and bulk nanocrystallline pure aluminum and conventionalpolycrystalline pure aluminum at different conditions.The results of high temperature oxidation of304stainless steel at900℃air for24hours indicate that，the main ingredients of oxide films on bulk nanocrystalline304stainless steel and conventional polycrystalline304stainless steel are Cr2O3, MnO2and O2；the depth of O2in oxide film on bulk nanocrystalline304stainless steel is lessthan that in the oxide film on conventional polycrystalline304stainless steel, thecontent of Cr in oxide film on bulk nanocrystalline304stainless steel is more thanthat in oxide film on conventional polycrystalline304stainless steel, the ratio of Cr3+/(Cr3++Cr0) and Mn4+/(Mn4++Mn0) is larger than that in the oxide film onconventional polycrystalline304stainless steel, Cr and Mn of bulk nanocrystalline304stainless steel are not easy to be oxided；the interactions of valence electrons ofoxide film on bulk nanocrystalline304stainless steel are stronger than that of oxide film on conventional polycrystalline304stainless steel, the work function of oxidefilm on bulk nanocrystalline304stainless steel is0.08eV larger than that onconventional polycrystalline304stainless steel.The results of high temperature oxidation of304stainless steel oxidized at950℃air for24hours indicate that, the main ingredients of oxide films on bulknanocrystalline304stainless steel are Cr2O3, and O2, the main ingredients of oxidefilms on conventional polycrystalline304stainless steel are Cr2O3, MnO2, and O2;compare with the conventional polycrystalline304stainless steel oxide film, the depthof O2in oxide film on bulk nanocrystalline304stainless steel is less than that in theoxide film on conventional polycrystalline304stainless steel, the content of Cr ismore, the ratio of Mn4+/(Mn4++Mn0) is lower, Mn are not easy to be oxided; thework function of bulk nanocrystalline304stainless steel oxide film improves0.07eV.The corrosion results of the aluminums in0.25mol/L of hydrochloric acid for9days indicate that, the surface of bulk nanocrystalline aluminum formed passive film,compared with conventional polycrystalline aluminum, the depth of Al3+and Cl-inthe surface of bulk nanocrystalline aluminum is less，the ratio of Al3+/(Al3++Al0) islower, and corrosion resistance is improved, the interactions of valence electrons onthe surface are stronger and the work function improves0.07eV.The corrosion results of bulk nanocrystalline304stainless steel in0.5mol/L ofhydrochloric acid for20days indicate that, the surface of bulk nanocrystalline304stainless steel formed passive film, compared with the conventional polycrystalline304stainless steel, the depth of Ni3+in the surface of bulk nanocrystalline304stainless steel is less and binding energy of Fe3+, Fe2+, Cr3+is higher, the ratios of(Fe3++Fe2+)/(Fe3++Fe2++Fe0)are lower, the Fermi energy in the surface of bulknanocrystalline304stainless steel improves0.20eV and the work function improves0.29eV. |
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