火力プラント復水器冷却管用銅合金のアンモニア水による腐食

抄録

The corrosion of Cu-base alloys in water containing 1-1, 000ppm NH₃ has been studied in view of the potential corrosion problems in the condenser tubes of thermal power plants. The results are as follows:
1) The corrosion resistance was in the increasing order of copper, aluminium brass, 9:1 cupronickel and 7:3 cupronickel. The dissolution rate of copper was high at higher concentrations of NH₃, i.e., 1, 000ppm and low at lower concentrations, i. e., 1-10ppm.
2) The corrosion resistance presumably depends upon the inherent nature of the surface films, which can be explained in terms of the pH-potential diagram.
3) Steel in contact with the Cu-base alloys gives negligible accelerating effect in spite of the fact that the former has more noble potential in the concentration region of 1, 000-10, 000ppm NH₃. The self-corrosion of the latters predominates in this region.