The synergy effect of elements on the oxidation resistance of a high-purity directionally solidification nickel-based superalloy

Abstract

A study on the film characteristics of a Cr2O3-forming nickel-based superalloy is conducted. A triplex structure is observed, in which Ta–Ti layer is developed between the external Cr2O3 and inner Al2O3 layer. When the exposure time increased, Ti atoms are divorced from the Ta–Ti layer, filling the voids inside the Cr2O3 layer, which improve the density of the external Cr2O3 layer and retard the inward penetration of the nitrogen. As a result, the degree of internal nitrides is reduced. Consequently, the synergy effect of Ta and Ti in the Cr2O3 forming alloy is beneficial to improve the oxidation resistance.