Hitachi, Ltd.

Kiyoshi Otake

Yoshitaka Kojima

Tetsuo Sasada

Hajime Toriya

Hideyuki Arikawa

Akira Mebata

A coated layer of this invention is composed of a lower alloy-coated layer 2 formed of an MCrAlY alloy whose principal element is Co or Co and Ni, an upper alloy-coated layer 1 formed of an MCrAlY alloy whose principal element is Ni and a portion 4 in which an Al content of the surface portion of the upper coated layer 1 is largest and is reduced gradually towards a more internal part. Manufacturing thereof involves the steps of forming the lower and upper coated layers and effecting an Al diffusion treatment into the upper coated layer. The upper coated layer having the portion which exhibits the large Al content contributes to a high-temperature anticorrosive property. A gas turbine blade is provided with the alloy-coated layer, wherein the lower coated layer incorporates a composite function to prevent a high-temperature corrosion of a base material when cracks are caused in the upper coated layer due to thermal stress. The gas turbine blade exhibits effects of improving the reliability and increasing a life-time.

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Takahagi, Japan

Kiyoshi Otake