Cast product having alumina barrier layer

Abstract

The present invention provides a cast product that can further enhance the stability of a barrier layer and can exhibit further superior oxidation resistance, carburization resistance, nitriding resistance, and corrosion resistance, when used under a high-temperature atmosphere, the cast product having a surface with a barrier layer comprising an Al-containing metal oxide expressed in (Al(1-x)M(x))2O3, where M is at least one of Cr, Ni, Si, and Fe, wherein the Al-containing metal oxide includes a solid solution of at least one of Cr, Ni, Si, and Fe with Al, in a relationship of Al/(Cr+Ni+Si+Fe)≥2.0 in an atomic % ratio, the barrier layer being composed of two layers consisting of a first Al-containing metal oxide layer and a second Al-containing metal oxide layer formed between the surface of the cast product and the first Al-containing metal oxide layer, and the second Al-containing metal oxide layer being greater than the first Al-containing metal oxide layer with respect to the atomic % ratio of Al/(Cr+Ni+Si+Fe), and having a thickness that is at least one fifth of a thickness of the barrier layer.

Dependencies are inferred from the claim text.