Abstract
Erosion by water drops is occurred on a low-pressure blade in the steam turbine. An electro-spark deposition (ESD) can fabricate a ceramics coating, high hardness, on a substrate which is remained at low temperature in the coating period. The applicability of ESD was examined for the steam turbine with the erosion. Cracks on the surface of the coating can be controlled by preheating of a substrate. The erosion rate of the ESD coating is 1/4 or less than one of the substrate. A bending strength of the ESD coating is equal to the substrate without the coating and the ESD coating is not detached form the substrate at the fracture point. These results show that the ESD coating has properties of the erosion resistance and the mechanical adhesion to the substrate.
