Tribochemical reactions of zinc diisobutyldithiophosphate in ester-mineral oil solution under boundary conditions

Four-ball wear experiments were performed with very low concentrations of zinc diisobutyldithiophosphate (ZDTP) dissolved in n-hexadecane/polyolester base stock. The experiments were conducted both under air and under argon atmospheres. The increased wear under an inert atmosphere is lower than unde...

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Bibliographic Details
Published in:Wear 1994-07, Vol.176 (1), p.1-8
Main Authors: Płaza, Stanisław, Kajdas, Czesław
Format: Article
Language:English
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Summary:Four-ball wear experiments were performed with very low concentrations of zinc diisobutyldithiophosphate (ZDTP) dissolved in n-hexadecane/polyolester base stock. The experiments were conducted both under air and under argon atmospheres. The increased wear under an inert atmosphere is lower than under air atmosphere. Tribochemical transformations of ZDTP were evaluated by measuring the concentrations of ZDTP and bis(O, O'-diisobutoxythiophosphinoyl) disulphide (DS) in the lubricant samples after wear tests, and hydrogen sulphide evolved by acidification of wear products from thiocompounds which were formed on the rubbing surface. At very low ZDTP concentrations high amounts of DS are formed, higher in an inert atmosphere, while none or very low amounts of thiocompounds are formed on rubbing surfaces. The results suggest that electron transfer processes play a very important role in the formation of corrosive species from esters.
ISSN:0043-1648
1873-2577
DOI:10.1016/0043-1648(94)90190-2