The mechanism of formation of boundary lubricating films during friction in a medium of di(2-ethylhexyl) sebacate

• Published in: Tribology international Vol. 165; p. 107222
• Main Authors: Boiko, Mikhail V., Sidashov, Andrey V., Boiko, Tatiana G., Burykin, Igor V., Uflyand, Igor E.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2022; Elsevier BV
• Subjects: Boundary lubricating films; Chemical bonds; Decarboxylation; Di(2-ethylhexyl) sebacate (DEHS); Free radicals; Friction; Iron; Lubricant; Lubricants; Lubrication; Mechanical activation; Metal surfaces; Organic chemistry; Oxide coatings; Oxide film; Unoxidized iron; Unoxidized iron; Decarboxylation; Di(2-ethylhexyl) sebacate (DEHS); Oxide film; Boundary lubricating films; Mechanical activation; Lubricant
• ISSN: 0301-679X; 1879-2464
• DOI: 10.1016/j.triboint.2021.107222

In this work, the mechanism of formation of boundary lubricating films during friction in synthetic oil di(2-ethylhexyl) sebacate (DEHS) was studied. The study of the kinetics of the interaction of DEHS with the metal surface showed that the formation of the boundary film proceeds in the first 40 s of friction. The unoxidized iron detected by the XPS method on the friction track accelerates the chemical transformations of lubricant molecules. Removing the oxide film from the friction surface is a mechanically activated process. When DEHS interacts with the iron surface, the reactions of decarboxylation of molecules proceed, as a result free radicals are formed. The sequence of transformations of free radicals and compounds with CC bonds leads to the formation of surface films upon friction. The retention of the film on the surface occurs due to the forces of interaction of the metal with free radicals or unsaturated bonds of organic molecules. •The formation of boundary lubricating films during friction in a synthetic oil di(2-ethylhexyl) sebacate (DEHS) was studied.•The formation of a boundary film occurs in the first 40 s of friction.•The unoxidized iron catalyzes the chemical transformations of lubricant molecules.•The formation of surface films during friction proceeds through successive transformations of free radicals and compounds with C C bonds.