Engineering durable sliding surfaces through multi-elemental layered double hydroxides

Adapting to the proliferative interest in compositionally flexible nanomaterials for in-situ solid tribofilm formation, this study explores the potential of a quinary layered double hydroxide (LDH) containing Ni 2 ⁺, Co 2 ⁺, Cu 2 ⁺, Fe 3 ⁺, and Al 3 ⁺ cations to generate mechanically adaptive films under severe tribological conditions. The incorporation of Cu 2 ⁺ has been found to induce structural distortion in LDH and then promote phase segregation within the LDH-derived tribofilm. However, these phenomena enable more extensive tribofilm coverage and greater benefit for wear resistance under severe loading at 100°C, albeit with inferior performance under less severe conditions, compared to the benchmark NiCoAl-LDH. Specifically, the resulting distinctive amorphous-crystalline nanocomposite tribofilm, derived from the quinary LDH, exhibits enhanced resistance to plastic deformation, thereby delivering excellent load-carrying capacity. These findings demonstrate that compositional complexity can promote a temperature- and load-dependent transition in tribofilm functionality, providing new insights into future high-entropy-inspired compositional synergy for engineering robust in-situ solid tribofilms from compositionally flexible LDH nanomaterials.