Solid/liquid lubrication behavior of nickel aluminum-silver alloy under seawater condition

The purpose of this work was to investigate whether a combination of solid lubrication with lubrication by seawater would be a feasible lubrication approach for marine applications such as propulsion system components, pumps, and other machinery. In particular, the friction and wear behavior of a high-strength, intermetallic-based solid-lubricating alloy (Ni₃Al-Ag alloy) coupled with Al₂O₃ ceramic was investigated in simulated seawater. Under seawater conditions, the Ni₃Al-Ag alloy exhibited a relatively low friction coefficient of 0.11–0.08 and a wear rate of about 1–2 × 10⁻⁷ mm³/Nm. It is proposed that the Ag alleviates plowing and adhesive actions of tribo-pair and retains chemical stability in seawater. Also, the seawater plays lubricating, cooling, and corrosive roles in the friction and wear response of the Ni₃Al-Ag alloy. The improvement in tribological properties under seawater conditions is attributed to the synergistic action of solid and liquid lubrication.