Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact

Abstract

Development of a novel in-situ technique for hydrogen uptake evaluation from a lubricated tribocontact, Tribiology International, http://dx.doi.org/10. 1016/j.triboint.2017.01.019 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

The multiple roles of a chemical tribofilm in hydrogen uptake from lubricated rubbing contacts

“…It can be understood from the total hydrogen permeation results that the lubricant additives used in this study, ZDDP and MoDTC, reduce the hydrogen uptake into the steel when they were added to the PAO base oil. This contradicts our previous results reported in [14] where the experiments were conducted at room temperature. This observation highlights the effect of temperature on hydrogen permeation into the steel when the ZDDP additive was used.…”

“…The key features of a hydrogen permeation curve was already described in [14]. The hydrogen diffusivity and total amount of hydrogen permeated in the sample can be calculated from the permeation transient curves using mathematical analyses derived from Fick's second law [16].…”

“…Those techniques only measured the hydrogen molecules that desorbed from the surface as hydrogen gas without giving any information about hydrogen entry into the tribo-pair. A new real-time method was demonstrated by the authors in [14,15] that can be employed to quantify hydrogen permeation into the steel from lubricated tribological contacts. This method is a combination of an electrochemical technique and a tribological contact and is based on a modified Devanathan-Stachurski (DS) setup.…”

“…The focus of this investigation is to understand the complex interplay between the lubricant composition and the tribofilm effect on hydrogen permeation rate. The newly developed technique, described in our previous paper [14], is used to determine whether lubricant formulation provides any improvement with regards to hydrogen uptake into the steel. The influences of two commonly used additives, zinc dialkyldithiophosphate (ZDDP) and molybdenum dithiocarbamate (MoDTC), as well as water contamination on hydrogen permeation rate were examined in this research.…”

A Study on the Tribofilm Growth and Tribological Properties of Tribofilms Formed from Zinc Dialkyl Dithiophosphate (ZDDP) and Molybdenum Dialkyl Dithiocarbamate (MoDTC)

“…Two key surface-active lubricant additives that are used in engine oils are zinc dialkyl dithiophosphate (ZDDP) as an antiwear additive and molybdenum dialkyl dithiocarbamate (MoDTC) as a friction modifier. Studies of the nature of tribofilms that are formed from ZDDP and MoDTC have been carried out over several decades [1][2][3][4][5][6]. Many studies have focused on the physical and chemical nature of tribofilms, particularly of elements such as Zn, S, and P, to obtain an improved understanding of and to improve lubricant performance [7][8][9].…”