Corrosive Wear Performance of Monel K500 Alloy in Artificial Seawater

Abstract

In corrosive wear, one of the most interesting phenomena is the synergism where both corrosion and wear are significantly increased, leading to much greater material losses than produced by the sum of material losses by either process alone. A systematic investigation was carried out in the present work to assess the electrochemical and corrosive wear behaviors of Monel K500 alloy sliding against alumina in artificial seawater using a pin-on-ring tribometer integrated with a potentiostat for electrochemical control. The open circuit potential clearly shifted to the cathodic direction due to sliding action. The corrosion current density was much higher under sliding than under corrosion only. Moreover, high normal load and rotation speed result in low open circuit potential and high corrosion current density. The material loss was greater under open circuit potential than under cathodic protection. Corrosion induced an increase in material loss. The material loss caused by a synergistic effect between corrosion and wear contributed to about 20% of the total material loss. The synergistic effect can be divided into wear-induced corrosion and corrosion-induced wear. Wear-induced corrosion was caused by damage to the passive film due to the sliding action of the counterbody, leading to accelerated dissolution. Corrosion can promote the growth and propagation of microcracks in the wear track, which causes corrosion-induced wear.

KEY WORDS:

• Corrosive Wear
• Seawater
• Monel K500 Alloy
• Synergistic Effect

ACKNOWLEDGEMENTS

This research was financially supported by the National Natural Science Foundation of China (Grant No. 51171059 and 50823008) and the Program for Innovative Research Team (in Science and Technology) in University of Henan Province (2012IRTSTHN008).

Review led by Jack Poley