PURPOSE: To impart a blade with both of corrosion-resisting and erosion-resisting properties, by applying at first a corrosion-resisting and acid-resisting coating layer over the entire surface of the blade, roughing the surface of said coating layer by use of a grinder or grinding paper, and then applying an erosion-resisting coating layer partially or wholly over the roughed surface of the first coating layer.

CONSTITUTION: A corrosion-resisting and acid-resisting coating layer 12, for instance, of a flake resin obtained by admixing scalelike glass flake to a resin of unsaturated polyester or vinyl ester is applied over the entire surface of a blade 11 which is made of an ordinary material such as SS41. After drying and curing the coating layer 12, its surface is roughed by use of a hand grinder or emery paper. Then, a coating layer 13 of a room temperature curing, erosion resisting material such as fluoroubber (Eight Seal, product name of Asahi Glass K.K.) is applied to the roughened surface of the coating layer 12, so that the blade 11 is imparted with both of corrosion-resisting and erosion-resisting properties over the entire surface thereof. According to the above arrangement, efficiency of the blade manufacturing operation can be improved by reducing the thickness of both of the coating layers 12, 13.