Damage to Copper Alloys from Sodium Chloride Particle Slurry

Abstract

Damage to copper alloys from the impact of sodium chloride particles in a slurry solution was investigated using a rotating cylinder electrode testing apparatus. A test for two types of copper alloys, 10Ni-Cu (C7060) and 30Ni-Cu (C7150), was carried out under a flowing slurry solution of 20 wt% at temperatures ranging from 20 to 80 °C. The impact condition of the particles was elucidated by means of measuring the shape and area of the impact scar generated by the impact of a solid particle in the apparatus, resulting in a velocity of 1.5 m/s and a narrow angle of 6°. Judging by the loss of mass for the specimen, the polarization resistance measured by electrochemical methods, and the surface appearance after the test, erosion was not caused by the impact of the sodium chloride. However, particle impact did accelerate corrosion. The damage to copper alloys from the impact of sodium chloride particles increased as the temperature of the solution increased. Corrosion damage for both copper alloys 30Ni-Cu and 10Ni-Cu were almost identical, although the content of the nickel differed. The properties of the corrosion product film that formed on the surface of the alloys were considered as part of the corrosion damage.