Additive-additive interactions: Search for synergistic FM-EP-AW composition

Sarin, Rakesh K.; Tuli, Deepak K.; Verma, Atul; Rai, Mangat; Bhatnagar, A. K.

doi:10.1016/0043-1648(94)90090-6

Cited by 26 publications

(14 citation statements)

References 23 publications

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“…In addition to the antiwear (AW) properties ZDDP provides to metal surfaces, ZDDPs possess antioxidant properties that are equally beneficial to the oil. Environmental implications of using ZDDP, however, have been addressed, and the necessity to use more environmentally friendly oil additives has become ever more apparent [1,2]. Consequently, this has forced oil suppliers to look for alternatives to ZDDP that are both ashless and contain reduced amounts of both phosphorus and sulfur.…”

Section: Introductionmentioning

confidence: 97%

The Correlation of Microchemical Properties to Antiwear (AW) Performance in Ashless Thiophosphate Oil Additives

et al. 2004

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X-ray absorption near-edge structure (XANES) spectroscopy at macro-scale (mm 2 ) and X-ray photoelectron emissions microscopy (X-PEEM) at micro-scale (lm 2 ) have been used to investigate the chemistry and spatial distributions of chemical species in tribochemical films generated from ashless thiophosphate oil additives on steel. Two different ashless thiophosphate additives were used: a triaryl monothiophosphate (MTP) and a dialkyldithiophosphate (DTP). Atomic force microscopy (AFM) and secondary electron microscopy (SEM) were also used to investigate the thickness and the topography of the tribofilms. Macro-scale XANES analysis showed that both ashless thiophosphates reacted with the steel surface to produce short to medium chain polyphosphates as the main constituent and sulfur species as minor component. From the PEEM experiment, it was found that the DTP tribofilm was microchemically heterogeneous, with areas of varying degrees of polyphosphate chain length. Conversely, MTP formed a tribofilm microchemically homogeneous, with areas comprised of only short chain polyphosphates. From, the different areas of polyphosphate chain length within the DTP tribofilm, colour-coded polyphosphate distribution map was generated. AFM, X-PEEM and SEM revealed that the DTP film was thicker and was composed of AW pads that were wider in area than MTP. This resulted in a smaller wear scar width (WSW) value for DTP. This is the first time that all these analytical techniques have been combined to better understand the nature of the tribofilms from ashless additives. We have concluded that an ideal AW film is comprised of a thick film with pad-like structures that are wider in area and microchemically heterogeneous, with areas of varying polyphosphate chain length.

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Section: Introductionmentioning

confidence: 97%

The Correlation of Microchemical Properties to Antiwear (AW) Performance in Ashless Thiophosphate Oil Additives

et al. 2004

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“…Laboratory synthesised oligomers of 1 -decene were prepared using sulphated zircona catalyst, as described elsewhere. 13 The laboratory synthesised hydrogenated oligomers are termed dimer, trimer, etc. …”

Section: Methodsmentioning

confidence: 99%

Detailed characterisation of polyalphaolefins and their branched structures using multi‐pulse NMR techniques

Kapur

Sarpal

Sarin

et al. 1998

J of Synthetic Lubrication

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“…On comparing the corresponding bright patches present across the Mo and S maps in Figs. (7)(8), it can be seen that there is a presence of MoS2 tribofilms originating from EP additives used in Samples (1,2). Similarly comparisons can be made by comparing bright patches in W and S maps on Fig.…”

Section: Edx Elemental Maps Of Wear Surfacementioning

confidence: 98%

“…Commonly used class of sulfur carriers in greases are sulfurized olefins/esters, dithiocarbamates, thiadiazoles, dithiophosphates etc. Sulfur containing EP additives are surface active and react with metal surface to form a sacrificial tribofilm that protects the underlying metal from further wear [6][7][8]. Most sulfurized species are compatible with other additives used in the formulation and in some cases, such as combination with aminic antioxidants or ZDDP's, they are synergistic, which makes them attractive for usage in fully formulated lubricants.…”

Section: Introductionmentioning

confidence: 99%

Wear and Friction of Greases Containing Organic and Inorganic Sulfur Carriers

2017

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Lithium based grease formulations are the most common lubricants used in industry today. Sulfur containing additives play a key role in improving wear and friction performance of these greases. The current study is focused on developing an understanding of characteristics of chemical bonding between sulfur carriers (MoS2, WS2 , MoDTC and organo tungstate ) and the interacting surfaces and evaluates their effect as anti-wear and anti-friction agents. ASTM D2266 and spectrum loading tests with varying loads while keeping other tests parameters constant were performed on the grease blends to understand effects of cyclic loading on tribochemical degradation of sulfur carriers. Tribofilms formed on the wear surface were analyzed using surface characterization techniques like SEM, EDS and Stereo Optical Microscopes. Wear scar diameter (WSD) and coefficient of friction (COF) were reported for the tests performed. This research aims to gain better insight on the atomic coordination or oxidation states of sulfur atom in additives and their correlation with anti-wear and extreme pressure performance when blended in greases.

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Additive-additive interactions: Search for synergistic FM-EP-AW composition

Cited by 26 publications

References 23 publications

The Correlation of Microchemical Properties to Antiwear (AW) Performance in Ashless Thiophosphate Oil Additives

The Correlation of Microchemical Properties to Antiwear (AW) Performance in Ashless Thiophosphate Oil Additives

Detailed characterisation of polyalphaolefins and their branched structures using multi‐pulse NMR techniques

Wear and Friction of Greases Containing Organic and Inorganic Sulfur Carriers

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