Effect of the noble metals addition on the oxidation behavior of Ni3Al

Jose Juan Ramos-Hernandez JESUS PORCAYO-CALDERON Jan Mayen Chaires GABRIEL ANGEL LARA RODRIGUEZ victor salinas JOSE-GONZALO GONZALEZ-RODRIGUEZ Lorenzo Martínez Gómez (2018)

This paper discusses the e1ect of the addition of noble metals on the microstructure, mechanism, and oxidation kinetics of the Ni3Al intermetallic alloy. Ni3Al was doped with 1% (atomic percent) of Au, Ag, Pd, and Pt. Oxidation behavior of the alloys was evaluated at 900, 1000, and 1100°C in O2 for 24 hours. XRD analysis showed that the addition of noble metals favored the oxide growth on preferential crystallographic planes. In addition, the preferential substitution of the noble metals in the Ni3Al structure modi>es the surface composition by increasing the Al/Ni ratio. It was observed that most of the alloys showed a subparabolic behavior, and only the intermetallic base and the alloy doped with Ag show a parabolic behavior at 900°C. ,e developed oxides were analyzed both super>cially and in cross section by scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDXA). It was evident that only the intermetallic base showed the formation of a duplex oxide scale (Al2O3/NiO). ,e alloys doped with noble metals showed the oxide growth practically of pure Al2O3. ,is was due to a decrease in the di1usion of the Ni cations because of the presence of the noble metals in the crystalline structure.

Financial support from Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico) (Project no. 159898 and Ph.D. scholarship to J. J. Ramos-Hernandez, Registration no. 202898) is gratefully acknowledged.

Artículo

INGENIERÍA Y TECNOLOGÍA CIENCIAS TECNOLÓGICAS TECNOLOGÍA DE MATERIALES PROPIEDADES DE LOS MATERIALES PROPIEDADES DE LOS MATERIALES