CYCLIC OXIDATION OF Ni-La2O3 COMPOSITE COATINGS ELECTRODEPOSITED ON NICKEL AND Fe26Cr STAINLESS STEEL
(1.State Key Laboratory for Corrosion and Protection; Institute of Corrosion and Protection of Metals; Chinese Academy of Sciences; Shenyang 110015
2.Laboratory of Atomic Imaging of Solids)
2.Laboratory of Atomic Imaging of Solids)
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