Search results

Pure 2,5‐dimercapto‐1,3,4‐thiadiazole (DMTD) disulfide dimer (DMS2) shows excellent four ball weld properties, however, the product is a solid material with relatively low initial seizure load and exhibits certain corrosion, which accelerate oxidation of the lubricant by catalytic effect on metals. The author make efforts to resolve problems said by design a novel thiadiazole complex.

The complex of thiadiazole dimmer and polyglycol (DMS2‐GL) was synthesized as ashless grease additive. The antiwear and load carrying properties of the additive and their synergistic effects was evaluated by four ball tester in four types of lubricant grease. Moreover, corrosion inhibiting properties of compositions said was investigated by copper corrosion test.

The additive DMS2‐GL possessed good load carrying capacity, and exhibits good synergistic antiwear and load carrying prop with rust inhibitor. In addition, dates obtained from copper corrosion test show that it does not corrode copper but coats the metal with a film, and could improve the anticorrosion of corrosive additives molybdenum dialkyldithiophosphate (MoDDP) and molybdenum dibutyldithiocarbamate (MoDTC) by forming protective films on rubbing surface, which contribute to improving corrosion inhibiting property of greases. Finally, the tribo‐chemical mechanism was proposed that thiadiazole dimer and polyglycol could coordinate with each other by polydentate surface interaction, which means thiadiazole rings interact with the metal surface, polyglycol affords a bridging technology linked thiadiazole dimmers so as to lighten loads and strengthen forces between thiadiazole dimmer moleculars.

This paper provides a good ashless additive which has good antiwear, extreme pressure and corrosion inhibiting properties, and fulfils an identified resources need, which can offer practical help in industrial applications and to an individual starting out on an academic career.

This paper aims to investigate the wear mechanisms, formations and effectiveness of tribofilms of new developed, antiwear additive which is called mercapthocarboxylate. The mercapthocarboxylate is a sulphur-based and non-phosphorus additive.

The effectiveness of the additive was examined through a set of laboratory endurance tests that applied with single cylinder spark ignition engine. Two types of lubricants were used to compare the engine tests which were thiophosphate (ZDDP) containing engine lubricant (phosphorus containing) and mercapthocarboxylate containing non-phosphorus and non-ash crankcase oil. Lubricants were tested under identical operating conditions for 100 hrs. The surfaces of cylinder liner and piston rings were inspected through optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques.

Catalysis-friendly and sulphur-based mercapthocarboxylate additive can be an alternative antiwear additive package for lubrication oil due to better wear performance when compared to ZDDP.

Sulphur-based mercapthocarboxylate is a new developed antiwear additive and was applied to lubrication oil in this study. This lubrication oil was tested in the real engine environment by using 100-hr engine bench tests.

This paper aims to investigate the tribological properties of 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ionic liquids (ILs) when used as lubricant additives in synthetic ester oil.

The 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ILs containing different cation-imidazolium and organo-ammonium were synthesized and characterized. Their tribological performances as lubricant additives were assessed on ball-on-flat tribological tester. Their compatibility with typical additives (such as viscosity improver, antioxidant, pour point depressant and anti-rusting agent) were evaluated on a four-ball friction and wear tester.

It was found that the synthesized ILs demonstrated more effective friction reduction and antiwear properties than the base synthetic ester oil. The ILs worked well with the other typical additives, such as viscosity improver, antioxidant, pour point depressant and anti-rusting agent.

The results of the experimental studies demonstrated the potential of 1,4-bis(2-ethylhexyl) sulfosuccinate anion-based ILs as additives for improving friction reduction and antiwear abilities of synthetic ester oil.

The purpose of this paper is to study the tribological performance of tri(hydroxymethyl)propane esters containing boron and nitrogen as lubricant additives in rapeseed oil.

Thermal degradation tests were performed to analyze their thermal stability using a thermo‐gravimetric analyzer. Two four‐ball testers were used to measure the tribological properties of tri(hydroxymethyl)propane esters containing boron and nitrogen as lubricant additives in rapeseed oil. The worn surfaces of steel balls were investigated by scanning electron microscope (SEM) and X‐ray photoelectron spectroscopy (XPS).

The results show that the tri(hydroxymethyl)propane esters containing boron and nitrogen have excellent thermal stability, good antiwear performance, improve the load‐carrying capacity, and possess friction‐reducing behavior especially at 98 N when they are used as additives in rapeseed oil. The results of XPS show that the adsorption and tribochemical reactions have been occurred to form a complex boundary lubrication film.

The paper illustrates two novel tri(hydroxymethyl)propane esters which contain B and N elements used as additives in rapeseed oil. The results are useful for further applications in advanced environment friendly lubricating oils and additives.

Interactions of different additive types for antiwear/friction modification on surfaces can be synergistic or antagonistic in nature. This paper aims to investigate whether there are interactions between different additives in the adsorption process and whether they synergistic or antagonistic. The yielded correlations will be validated with tribological experiments to answer the question whether synergistic effects in adsorption also lead to synergistic effects in wear reduction.

In a representative study, zinc dialkyl-dithiophosphate and dithiophosphate were elaborated in combination with two different friction modifiers, a glycerol monooleate and an organic friction modifier. As base oils, mineral oil and poly alpha olefine were used. The adsorption behavior was studied via quartz crystal microbalance with dissipation using Fe₂O₃ coated quartz crystals. The tribological performance was evaluated in a ball-on-three disk tribometer. White light interferometry was used to determine the wear volume and X-ray photoelectron spectroscopy depth profiles of the tribofilms were obtained on selected systems.

The combination of dithiophosphate and an organic friction modifier (OFM) revealed a synergistic effect in terms of wear. If the initially formed films are viscoelastic, the third body formation during a tribo experiment is more pronounced and thereby wear can be reduced. As a mechanism, the adsorption of the OFM on the formed antiwear layer is proposed.

Correlating the analytical findings with performance experiments provides further understanding of the interactions between different constituents and their implications on film formation processes and wear reduction mechanisms.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-07-2019-0293/

The purpose of this paper is to study the antifriction, antiwear and tribolayer formation properties of the trihexyltetradecylphosphonium bis(2,4,4-trimethylpentyl) phosphinate ionic liquid (IL) as additive at 1 wt.% in two base oils and their mixtures, comparing the results with those of a commercial oil.

The mixture of the base oils used in the formulation of the commercial oil SAE 0W20 plus the IL was tested under rolling/sliding and reciprocating conditions to determine the so-called Stribeck curve, the tribolayer formation and the antifriction and antiwear behaviors.

The use of this IL as additive in these oils does not change their viscosity; improves the antifriction and antiwear properties of the base oils, making equal or outperforming these properties of the SAE 0W20; and the thickness and formation rate of the tribolayer resulting from the IL-surface interaction is highly dependent on the type of base oil and influence on the friction and wear results.

The use of this IL allows to replace partial or totally commercial antifriction and antiwear additives.

The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-05-2020-0179/

The purpose of this paper is to study the dispersion and tribological properties of liquid paraffin with aluminum nanoparticles as additive, which are prepared by the surface‐modification method using oleic acid (OA).

The dispersion stability of aluminum nanoparticles in liquid paraffin is measured by spectrophotometry, which can be optimization by Taguchi method. The tribological properties are evaluated by using a ball‐on‐ring wear tester.

The results show that few concentrations of aluminum nanoparticles as additives in liquid paraffin have better antiwear and antifriction properties than the pure paraffin oil. Scanning electron microscopy and energy dispersive spectrometer analyses can show that the thin films on the rubbing surfaces can be formed by these aluminum nanoparticles, which not only bear the load but also separate the both interfaces, thus the wear and friction can be reduced.

Machine components and mechanism pairs rely on high‐quality lubricants to withstand high temperature and extreme pressure. Extreme pressure and antiwear additives are typically adopted to improve the tribological performance of a fluid lubricant in reducing friction and surface damage under severe conditions.

This paper aims to contrastively investigate the antioxidant behavior and tribological performance of a novel multifunctional additive (PBT) and dialkyldithiophosphate (ZDDP) in complex lithium grease (CLG).

PBT was successfully synthesized through esterification reaction. The antioxidant behavior of PBT and ZDDP was investigated by thermal analysis, and meanwhile, their tribological performance was evaluated by Optimol SRV-IV oscillating reciprocating friction and wear tester (SRV-IV test) and MRS-1J four-ball tester (Four-ball test). Furthermore, their anticorrosion ability was determined by copper strip corrosion test.

Four-ball tests showed that the extreme pressure property of PBT was a little inferior to that of ZDDP. Besides, all the other results demonstrated that PBT showed more superior antioxidation stability, friction-reduction and antiwear ability, as well as anticorrosion performance than ZDDP.

This work provides a study of hindered phenol derivative as a multifunctional additive in lubricant grease, which can contribute to the development of substitution of ZDDP.

Environmental regulations have called for reduction of phosphorus content in engine oils because this element strongly deactivates the catalyst in automotive catalytic converters. The primary source of phosphorus is zinc dialkyl(aryl)dithiophosphate (ZDDP). Therefore, to protect catalyst ZDDP is replaced with other additives or its amount in engine oil is reduced. Zinc dialkyl(alkylaryl)ethoxy dithiophosphates (ZEDPs), a novel derivative of dithiophosphate additive, soluble in lubricating base oils were synthesized and used to replace containing more phosphorus ZDDP.

Tribological properties of ZEDPs were evaluated using four‐ball and the ball‐disc tribometers. The ZEDPs thermal stability and worn surface were analysed using TGA, XPS techniques.

ZEDPs significantly reduce the friction and wear under boundary, mixed and hydrodynamic lubrication regimes. Friction and wear properties are dependent on chemical structure of additives, their surface active behavior in tribological system and frictional parameters. The effectiveness of friction and wear reduction increases with the concentration of lubricating oil additive solution and depend on the amount of the additive adsorbed on the surfaces. ZEDPs are much more thermally stable than ZDDPs. The XPS shows that the tribochemical films formed on rubbing surfaces contain zinc and iron phosphates and sulphates.

The effect of the number of etoxy groups in ZEDPs molecules on their tribological properties was not investigated.

ZEDPs were synthesized and can be a potential replacement for ZDDP.

ZEDPs were first investigated in lubrication of steel‐steel frictional contact and results indicate that they can be used as additives in combustion engine base oil.

Additives are incorporated in engine oils to improve existing desirable properties of base stocks and to impart new specific properties required by modern engines. The additives include antioxidants, detergents, dispersants, corrosion and rust inhibitors, viscosity index improvers, pour point depressants, foam inhibitors and tribological agents. In this study, the effect of boron oil fortifier added into the base oil on friction coefficient and pressure distribution was investigated between sliding surfaces of engine journal bearings. Experiments were performed firstly using only base oil at different speeds and loads. Then, this test was repeated with different concentration ratio of 1, 3, 5 and 10 percent commercial boron additive.