Effect of seawater intrusion on tribological properties of brass/steel pairs in hydraulic oil

In seawater hydraulic pumps, the cross-contamination between oil and seawater is frequently observed, significantly influencing both the operational efficiency and the service life of the pumps. In this research, the tribological behavior of brass/steel pairs in hydraulic oil with artificial seawater (3.5 wt.% NaCl) intrusion was examined. The results revealed that the NaCl solution concentration in the emulsions has an essential influence on the lubrication state and wear mechanism of brass/steel pairs. As the viscosity of the emulsion increases, the lubrication state at the wear interface improves, which reduces the contact stress at the friction interface and reduces abrasive damage. Moreover, with the increase of NaCl solution concentration, the primary wear mechanism underwent two transitions: initially shifting from abrasive wear to a combination of adhesive and corrosion wear, ultimately evolving into corrosion wear. These findings are crucial for understanding the tribological behavior of brass/steel pairs in seawater-in-oil emulsions. This study provides a valuable experimental basis for improving the performance of the marine equipment.