Tribology in Industry (Sep 2019)
Studying the Possibility of Using Complex Esters as AW/EP Additives
Abstract
In this work, the possibility of using esters of organic acids as antiwear additives to lubricants has been investigated. Work has two targets. The first of these is the verification of theoretical statements about the mechanism of action of anti-wear additives. According to the authors ideas, the influence of additives on the formation and properties of a polymolecular adsorption layer is the predominant factor. These ideas are based on the general laws of liquids adsorption on the solid surface. In addition, they correspond to the properties of AW/EP additives used in modern lubricants. The second goal is to develop justified approaches to creating AW/EP additives for biodegradable lubricants based on vegetable oils and synthetic esters. Additives to these materials must meet several requirements. In particular, they must be chemically compatible with vegetable oils and not have bactericidal properties. For use in two-stroke internal combustion engines, additives must contain a minimum amount of sulfur, phosphorus and ash elements. Esters of dibasic and tribasic organic acids with higher alcohols were chosen as promising objects of study. Studies have been conducted on the example of the monoester of maleic acid, esters of tartaric and aconitic acids with hexadecyl alcohol. The results of measurements of the anti-wear properties of these substances when added to vegetable oil are given. As a result of these tests, a high AW/EP effectiveness of aconitic ester was found. This compound also showed efficacy when it was added to petroleum oil without additives and to standard gear oil. The measurements were simultaneously carried out in the SUSU laboratories, and at Sofia University in several stands under various friction conditions. The results showed that the use of new additives in hydrocarbon petroleum oil without additives gives AW effect, which is slightly lower than ZDDP. The investigated additive can be used in standard compositions of additives to motor and transmission oils. The results of the study indicate the prospects for the use of esters of polyatomic acids as AW/EP additives for lubricants of various origins.
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