Tribocorrosion behavior of nickel aluminum bronze in seawater: Identification of corrosion-wear components and effect of pH

摘要

This work is focused on the influence of solution pH on the tribocorrosion behavior of a tribosystem between nickel aluminum bronze (NAB) and Al2O3. To explore the interaction mechanism between wear and corrosion, a pin-on-disc tribometer equipped with a potentiostat was used and the frictional, electrochemical responses were reported in situ during tribocorrosion processes as a function of the solution pH. Results revealed that a high pH solution would aggravate corrosion and give rise to accelerated material loss. In addition, the corrosion mechanism of NAB was dependent on solution pH, that is, the NAB oxidation was driven by the dissolution of K-II phase at pH below 4.2, whereas its anodic behavior was dominated by the preferential corrosion attack of copper-rich a-phase within the alpha+K-III eutectoid when pH was higher than 4.2. Combined with quantitative calculation at various pHs, it was found that the pure mechanical and corrosion-accelerated wear, presented delamination and abrasion, were the main reasons for material degradation.