Probing the Synergy of Blended Lithium Complex Soap and Calcium Sulfonate Towards Good Lubrication and Anti-Corrosion Performance

Abstract

Thickener plays a significant role on the performance of grease, including rheological property, chemical and thermal stability, colloidal and mechanical stability, and so forth. Here, lithium complex-calcium sulfonate (L/C) greases were synthesized via regulating lithium complex soap and calcium sulfonate in the molar ratio of 1:2, 2:1 and 1:1, along with thickening the polyalphaolefin (PAO40). The physicochemical properties, corrosion resistance and tribological performance were evaluated in detail, with lithium complex grease and calcium sulfonate grease as a comparison. The results show that the as-prepared L/C greases have good corrosion resistance for low-carbon steel due to unique reversed micelles of calcium sulfonate and sealing function. The regulation of lithium complex soap and calcium sulfonate in different molar ratios achieves the considerable adjustability of grease's physicochemical and tribological properties due to the component/structure of thickener and its sensitivity to base oil. The grease with formulation of L/C = 1:2 gives the best lubrication function depending on not only the thickener's component and structure, but also the synergistic lubrication of grease-film and tribo-chemical reaction film composed of Fe 2 O 3 , FeO(OH), CaO, CaCO 3 and LiOH.

Optimization of the Tribological Performance and Service Life of Calcium Sulfonate Complex—Polyurea Grease Based on Unreplicated Saturated Factorial Design

“…As shown in Table 3, the factors that may affect the tribological properties and service life of lubricating grease during the preparation process of CSCPG are listed, including the proportion of three thickening agents [29]: overbased calcium sulfonate T106A (coded A), polyurea thickening agent (coded C), and composite calcium soap (coded D); base oil 40 • C kinematic viscosity (coded B) [14]; the proportion of the content of the two additives: antioxidant (coded E) [30] and nano-solid friction reducers [10][11][12] (coded F); reaction time: conversion reaction time T 1 (coded G), thickening reaction time T 3 (coded H); reaction temperature: conversion reaction temperature t 1 (coded J), thickening reaction temperature t 3 (coded K), and grinding gap (coded L) during post-treatment [31]. Table 3 also provides the range of values for each factor, where the initial value refers to the values of each factor before optimization, and the maximum and minimum values are the allowable range of values for each factor obtained based on experience.…”

Tribological Behavior of WS2 Nanoparticles as Additives in Calcium Sulfonate Complex–Polyurea Grease

“…Wu C [29] found that nano-CuO as an additive exhibits better friction reduction performance in polyurea grease than in CSCG. Researchers have also prepared lithium complex-calcium sulfonate greases by mixing lithium composite soap and calcium sulfonate, which have good corrosion resistance for low-carbon steel due to the unique reversed micelles of calcium sulfonate and the sealing function [30].…”