In this study, lauric acid was introduced during the growth of a thickener of calcium sulfonate grease, and the low-temperature fluidity and drop point of the grease were greatly improved by regulating the morphology of the thickener and the oil-fixing ability of the surface. The aspect ratio of the thickener was increased from 1 to 5, and the specific surface area was increased by 40.12%. Similarly, at low temperatures, the viscosity decreased by 11.63%, and the drop point increased by nearly 100 °C. A comparison of the effects of lauric acid, amines, and alcohols with different polar end groups on the surface adsorbability and wettability of the thickener revealed that the adsorption qualities of the three molecules were similar, but only lauric acid and amines significantly improved the lipophilicity of the surface of the thickener and increased the drop point of the grease by nearly 100 °C. Through molecular dynamics simulation, the alkyl chains of linear acid and amine molecules adsorbed on the surface of the thickener are found to be almost perpendicular to the surface of the thickener, which makes the interface base oil difficult to slip, increases the adsorbed oil content and the effective radius of the thickener, and effectively increases the drop point of the grease. The long alkyl chain of the linear-chain alcohol molecules is almost parallel to the surface of the thickener, which has little effect on the physicochemical properties of the grease.

CeO₂ nanoparticles are potential anti-wear additives because of their outstanding anti-wear and load-bearing capacity. However, the shear-sintering tribo-film formation mechanism of oxide nanoparticles limits the tribo-film formation rate and thickness greatly. In this study, by compounding with zinc dioctyl dithiophosphate (ZDDP), ultra-fine CeO₂ nanoparticles modified with oleylamine (OM) can quickly form 2 μm ultra-thick tribo-film, which is 10‒15 times thicker than that of ZDDP and CeO₂, respectively. The ultra-thick tribo-film presents a nanocomposite structure with amorphous phosphate as binder and nano-CeO₂ as filling phase, which leads to the highest loading capacity of composite additives. The results of adsorption experiments tested by dissipative quartz crystal microbalance (QCM-D) showed that the P_B value of additive has nothing to do with its equilibrium adsorption mass, but is directly proportional to its adsorption rate in 10 s. The compound additive of CeO₂ and ZDDP presented the co-deposition mode of ZDDP monolayer rigid adsorption and CeO₂ viscoelastic adsorption on the metal surface, which showed the highest adsorption rate in 10 s. It is found that the tribo-film must have high film forming rate and wear resistance at the same time in order to achieve super thickness. Cerium phosphate was formed from ZDDP and CeO₂ through tribochemistry reaction, which promotes the formation of an ultra-thick tribo-film with nanocomposite structure, which not only maintains the low friction characteristics of CeO₂, but also realizes high P_B and high load-carrying capacity.