Steam turbine rotor blade, method for manufacturing steam turbine rotor blade, and steam turbine

摘要

A steam turbine rotor blade for forming a turbine rotor cascade of a steam turbine includes a rotor blade main body having a blade portion, a blade base portion and a first coupling portion, which has first facing surfaces, provided on opposite end sides of the blade portion, and a second coupling portion provided in an intermediate portion of the blade portion and having second facing surfaces. The steam turbine rotor blade also includes a coating layer which is made of a Co-based alloy having a single composition on a surface of at least one of the first and second facing surfaces with a diffusion layer having a thickness of 10 μm or less provided between the coating layer and the surface.