EFFECT OF ELECTRODEPOSITED Ni-La_2O_3 COMPOSITE FILM ON OXIDATION RESISTANCE OF γ-TiAl
PENG Xiao;TANG Zhaolin;LI Tiefan; WU Weitao(State Key Laboratory for Corrosion and Protection; Institute of Corrosion and Protection of Metals; The Chinese Academy of Sciences; Shenyang 110015)
Cite this article:
PENG Xiao;TANG Zhaolin;LI Tiefan; WU Weitao(State Key Laboratory for Corrosion and Protection; Institute of Corrosion and Protection of Metals; The Chinese Academy of Sciences; Shenyang 110015). EFFECT OF ELECTRODEPOSITED Ni-La_2O_3 COMPOSITE FILM ON OXIDATION RESISTANCE OF γ-TiAl. Acta Metall Sin, 1998, 34(3): 319-324.
Abstract A novel electrodeposited Ni-La2O3 composite coating with a superior oxidation resistance has been applied as a protective coating of γ-TiAl intermetallic compound against high temperature through a technique of the codepostion of tiny La2O3 particles with nickel onto to the surface of the intermetallic. Both experimental results of isothermal okidation at 1000℃ for 48h and cyclic oxidation at 900℃ for 330 h showed that the poor oxidation resistance of the intermetallics was significantly improved after the intermetallics was coated with the composite film. SEM/EDX and EPMA results indicated that the preferentially formed La2O3-modified NiO layer on the Ni-La2O3 electrodeposited composite film could block growth of TiO2 out of the surface scale and favor the formation of two continuous protective Al2O3 layers. The two alumina layers, one beneath the La2O3-modified NiO layer and the other close to the subsurface zone in the substrate, are responsible for maintenance of the superior oxidation resistance of the coated γ-TiAl during the long-term thermal cycling.
