Erosion-Corrosion Behavior Of70/30Cu-Ni Alloy In Artificial Seawater

Erosion-corrosion behavior in different velocities(0m/s,3m/s and6m/s)and impactangles(0°,30°,45°,60°and90°) artificial seawater, immersion corrosion behavior in a longtime(90days) and Erosion-corrosion behavior of70/30Cu-Ni Alloy after they have producedfilm, were investigated by Electrochemical Impedance Spectroscopy (EIS)，ElectrochemicalNoise (EN), Scanning Electron Microscopy(SEM), potentiodynamic polarization curves, onan impingement jet system.Erosion-corrosion behavior of70/30Cu-Ni Alloy in uncontaminated and contain silicondioxide artificial seawater was investigated, the results show: impedance of3m/s was greaterthan6m/s, but they were all less than impedance of0m/s. The impedance of0m/s wasgradually increased with time, the impedance of3m/s and6m/s only had a small variationwith time. The impedance of3m/s and6m/s decreases with the increasing of impact angles.Noise resistance of0m/s was gradually increased with time, noise resistance of3m/s and6m/s only had a small variation with time, and noise resistance of3m/s was greater than6m/s.Noise resistance of3m/s and6m/s decreases with the increasing of impact angles.Potentiodynamic polarization curves of0m/s had a narrow passivation region afterimmersion for10hours, potentiodynamic polarization curves of3m/s and6m/s not hadpassivation region after erosion-corrosion for10hours. Cathode current density of0m/s wasgreater than3m/s and6m/s. The impedance of erosion-corrosion in uncontaminated artificialseawater was greater than in contains silicon dioxide artificial seawater. The noise resistanceof erosion-corrosion in uncontaminated artificial seawater was greater than in contains silicondioxide artificial seawater. Some pittings had discovered on the surface of70/30Cu-Ni Alloyafter immersion10hours in artificial seawater, surface wear marks by sandpaper grindingwere very clear; much pitting had discovered on the surface of70/30Cu-Ni Alloy aftererosion-corrosion10hours in uncontaminated artificial seawater, surface wear marks bysandpaper grinding were not very clear compared with immersion corrosion, with theincreasing of impact angles, surface wear marks turned more unclear; much pitting whichlooked like scales, had discovered on the surface of70/30Cu-Ni Alloy after erosion-corrosion10hours in contain silicon dioxide artificial seawater, when velocity was6m/s, it had morepittings than3m/s, with the increasing of impact angles, there were more pittings. Immersion corrosion behavior of70/30Cu-Ni Alloy in90days was investigated, theresults show: impedance of immersion was quickly increased with the prolonged time in40days, impedance was reach maximum when immersion for40to50days, impedance ofimmersion concussive change after immersion50days. Change of noise resistance followtime of immersion was the same as impedance of immersion. Erosion-corrosion behavior of70/30Cu-Ni Alloy was investigated after they have produced film, the results show: inuncontaminated artificial seawater, the impedance of erosion-corrosion with film was greaterthan without film, matrix was effectively protected by film. In contain silicon dioxideartificial seawater, the impedance of erosion-corrosion with film almost as without film,matrix was ineffectively protected by film.