Abstract:A coating of nickel with La₂O₃ oxide particles has been codeposited onto the surface of nickel as well as Fe₂₆Cr stainless steel for improving their high temperature oxidation resistance. Both specimens of nickel and Fe₂₆Cr stainless steel deposited with NiLa₂O₃ composite coatings exhibited a much better resistance to cyclic oxidation in air at 900 ℃ than those of the two bare materials. Electron probe microscope analyses revealed that, for both NiLa₂O₃ coated nickel and Fe₂₆Cr stainless steel, a La₂O₃ rich NiO layer close to the gas/scale interface was produced after the composite film had been thoroughly oxidized during the thermal cyclic processes. It is believed that the enhancement of cyclic oxidation resistance of nickel and Fe₂₆Cr stainless steel deposited with the NiLa₂O₃ codeposits coatings may be related to the incorporation of La₂O₃ particles (especially those with the size of several nanometers) into NiO scale. The mechanism of the effect of La₂O₃ dispersoids on the oxidation behavior of nickel and Fe₂₆Cr stainless steel was also discussed in details.  

Key words: nickel Fe₂₆Cr stainless steel cyclic oxidation electrodeposited NiLa₂O₃ composite film