Investigation of tribological characteristics of lubricant grease based on Solidoil and urea resin thickener

The results of laboratory investigation of the tribological characteristics of a new grease based on Solidol, a polyurea thickener providing an increase in the dropping point to 118 °C, and a complex of additives are presented. It has been established that the proposed lubricant is efficient in a wider temperature range, provides higher antiwear properties for tribocoupling parts and considerably reduces friction losses during boundary lubrication in comparison with the original grease Solidol. The developed composition of the lubricant grease is supposed to be used when operating road construction machines in the tropical conditions of Vietnam.

Comparative study on corrosion resistance and lubrication function of lithium complex grease and polyurea grease

In this study, lithium complex grease (LCG) and polyurea grease (PUG) were synthesized using mineral oil (500SN) and polyalphaolefin (PAO40) as base oil, adsorbed onto lithium complex soap and polyurea as thickeners, respectively. The effects of grease formulation (thickener and base oil with different amounts (80, 85, and 90 wt%) on the corrosion resistance and lubrication function were investigated in detail. The results have verified that the as-prepared greases have good anti-corrosion ability, ascribed to good salt-spray resistance and sealing function. Furthermore, the increase in the amount of base oil reduces the friction of the contact interface to some extent, whereas the wear resistance of these greases is not consistent with the friction reduction, because the thickener has a significant influence on the tribological property of greases, especially load-carrying capacity. PUG displays better physicochemical performance and lubrication function than LCG under the same conditions, mainly depending on the component/structure of polyurea thickener. The polyurea grease with 90 wt% PAO displays the best wear resistance owing to the synergistic lubrication of grease-film and tribochemical film, composed of Fe2O3, FeO(OH), and nitrogen oxide.