Ga-based liquid metal as an extreme pressure lubricant for steel-ceramic pairs

Extreme pressure lubrication is a crucial engineering problem for many mechanical assemblies. Herein, an extraordinary and novel functional material, Ga-based liquid metal (GLM), is found to be a promising extreme pressure lubricant for steel-ceramic sliding pairs and bears applied load above 1500 N. A Ga-rich metallic tribofilm forms on the frictional interface during sliding, providing good lubricity and bearing capability. In addition, the lubrication performance of GLM strongly depends on its composition and the contacting materials. Ternary Ga-In-Sn alloy has superior lubrication to binary Ga-In alloy. GLM lubrication is more effective on the interfaces of AISI52100/Si3N4 than on those of AISI52100/SiC sliding pairs.