In order to obtain metal materials that are resistant to erosion and corrosion, erosion and corrosion of the copper alloy JIS BC 6 in flowing water was observed at different flow velocities, water temperatures and content of oxygen dissolved in the water. The results were compared with those obtained using gray cast iron (FC 20) and austenitic cast iron (FCDA-Ni Cr 20 2). The weight loss of the copper alloy was found to be more dependent on the flow velocity and the content of dissolved oxygen in the flowing water than on the temperature of the water. In the early stages of flow after immersion, a thin layer composed of Cu(OH)2 and CuO was formed on the surface. But in the later stages, a strong, thick film composed of Cu(OH)2, CuCl2 and CuO was formed. Erosion and corrosion of the copper alloy, therefore, was governed by oxygen diffusion through the oxidized film. The copper alloy was more resistant to erosion and corrosion than both the gray cast iron and the austenitic cast iron.
