Patent ID: 7285337

Claim:
A heat-resistant Ni-alloy composite having excellent high-temperature oxidation resistance, comprising: a Ni-alloy substrate containing Cr and a multi-layer surface structure formed on the Ni-alloy substrate, comprising an inner Cr layer with Cr content of about 85 atomic percent to about 95 atomic percent in the form of α-Cr phase composed of precipitates between the substrate and an outer layer and the outer layer composed of a β phase (Ni—Al—Cr) and a γ′ phase (Ni 3 Al(Cr)), wherein the Al content in the outer layer is homogeneous and is at least 20 atomic percent, and the Cr content in the outer layer is saturated, wherein said multi-layer surface structure is formed by diffusing Al in a NiAl 3 with Ni 2 Al 3 layer formed on the Ni-alloy substrate containing Cr.