Electrochemical Studies of the Automotive Lubricant Additive Zinc n‐Dibutyldithiophosphate

Publisher Website
Google Scholar
Abstract
Zinc dialkyldithiophosphates (ZDTPs) are widely incorporated in lubricant formulations as antioxidant and antiwear additives. Using the model compound zinc n dibutyldithiophosphate (Bu-ZDTP) in dimethylformamide (DMF) solution, cyclic voltammetry is applied to a detailed study of Bu-ZDTP electro‐oxidation. Bu-ZDTP is shown to be oxidized in a chemically irreversible electron transfer process under diffusionf‐limited conditions. A similar study of Bu-ZDTP reduction revealed nucleation of zinc at the electrode surface. A chronoamperometric investigation of zinc deposition classified the nucleation according to a progressive mechanism with the diffusion coefficient for Bu‐ZDTP in (DMF) solution as . By comparison with diffusion coefficients obtained via Levich analysis of Bu-ZDTP oxidation, the oxidation process is assigned as a two‐electron transfer. The use of atomic force microscopy as a means of directly visualizing zinc nuclei formed as a result of Bu-ZDTP reduction is described. © 1999 The Electrochemical Society. All rights reserved.

This publication has 0 references indexed in Scilit: