Steam turbine and steam turbine blade

A steam turbine blade, used for a steam turbine including:

• a turbine rotor;
• a rotor blade implanted to the turbine rotor;
• a stator blade provided at an upstream side of the rotor blade;
• and a turbine casing supporting the stator blade and including the turbine rotor, the rotor blade and the stator blade, in which a stage is formed by a pair of the rotor blade and the stator blade, and a steam passage is formed by arranging plural stages in an axial direction of the turbine rotor, as the stator blade or the rotor blade,
• wherein a surface treatment including coating a ceramics precursor and decomposing the ceramics precursor by a heat treatment after coating the ceramics precursor is performed to form a ceramic layer directly on at least a part of a surface of the stator blade and a surface of the rotor blade exposed at approximately 350° C. to 610° C. so as to suppress an increase of a surface roughness caused by oxidation;
• and
• wherein the surface roughness is one in which a maximum height Rmax after the surface treatment is 1.6 μm or less.