Ionic Liquid Functionalized Layered Double Hydroxides Achieve Near-Zero Wear on Steel–Steel Contacts

Layered double hydroxides (LDH), characterized by a unique layered structure with exchangeable interlayer anions, are an important class of inorganic functional materials. Their tunable composition and structure make them promising candidates as lubrication additives. However, LDH are limited in their long-term dispersibility and stability, and their compatibility with industrial lubrication mixtures has yet to be fully investigated, so their application in lubrication remains a major difficulty. This study involved the intercalation modification of LDH by alkyl alcohol amine phosphate ionic liquids (PIL) to ensure their stable distribution in water. The results showed that the use of ionic liquid intercalated double hydroxide (PIL-LDH) as an aqueous lubricant additive could significantly reduce friction and wear resistance and even reduce peak wear by 99.7%. PIL-LDH achieves self-lubrication and self-healing through interlayer slip and PIL release combined with chemisorbed and physically deposited layers.