LAUSR

Abstract Extreme pressure lubrication is a great challenge for many mechanical systems like bearings and gears. Here, an novel functional material based on Ga-based liquid metal has been applied to successfully lubricate the steel-ceramic sliding pairs at extreme high load (1500 N), which significantly outperforms other liquid lubricants like oil and ionic liquid. Ga-based liquid metal provides a low friction coefficient (0.11–0.23) and wear rate (10−8-10−7 mm3/Nm) of AISI 52100 steel disc (C0.98-1.10Mn0.25-0.45P≤0.025S≤0.025Si0.15-0.30Cr1.30-1.60Fe96.5-97.32, mass %; American Iron and Steel Institute standard) when it slides against Si3N4 balls over a load range 100–1500 N. To elucidating these interesting results, the lubrication mechanisms of Ga-based liquid metal are studied by tribo-surface analysis.