Abstract This study investigates the liquid-phase deposition (LPD) of carbonaceous tribopolymeric films from cyclopropane-carboxylic acid (CPCa), an additive dissolved in polyalphaolefins, under boundary-lubricated sliding conditions. In this approach, the lubricant acts as a carrier for a reactive chemical precursor, while the sliding contact functions as a tribochemical reactor that drives in-situ film formation. Ball-on-disk sliding experiments were conducted using n-dodecane containing 5 wt.% CPCa on AISI 52100 and D2 steels of identical hardness but different chromium content. The addition of CPCa reduced wear coefficients by approximately an order of magnitude on both steels. Raman spectroscopy confirmed the formation of disordered, sp 2 -rich carbon tribopolymeric films that were soluble in dichloromethane, distinguishing them from conventional PVD/CVD-deposited amorphous carbon coatings. Confocal profilometry revealed heterogeneous tribofilm thicknesses of ~ 100 nm within the contact. Upon CPCa removal from the lubricant, these tribofilms acted as sacrificial, wear-protective layers, with substantially greater durability on chromium-rich D2 steel than on 52100 steels. These results demonstrate that CPCa-derived tribopolymeric films can be formed rapidly by liquid-phase deposition and provide effective wear protection, highlighting tribocatalysis with appropriate chemical precursors as a promising pathway for replenishable, in-situ carbon coatings.
Hassan et al. (2026) studied this question.