Antifriction Additives Research Articles

МОДИФИКАТОРЫ ТРЕНИЯ В СМАЗОЧНЫХ МАТЕРИАЛАХ – ЭФФЕКТИВНЫЙ ИНСТРУМЕНТ ПОВЫШЕНИЯ ЭНЕРГОЭФФЕКТИВНОСТИ ДВС

In today's world, energy efficiency is one of the key factors in the development of technologies. Particular attention is paid to internal combustion engines (ICE), which are actively used in various industries and transport. Since overcoming friction consumes up to a quarter of the energy resources consumed, one of the promising tools for improving the energy efficiency of these engines is the use of friction modifiers in lubricants. The article considers the main types of antifriction additives with a brief description of the mechanisms of their action, the main advantages and disadvantages, tested the most common friction modifiers of different nature in the composition of 10w-40 API CI-4 oil on the friction machine 2070 SMT-1 and quantitatively shows the difference in the effectiveness of the selected additives, made conclusions about the most effective additives and dosages of input, as well as the factors limiting the introduction of lyophilic molybdenum modifiers.

Studies on Engine Oil Degradation Characteristics in a Field Test with Passenger Cars

Nowadays, a car’s engine oil change interval is an essential factor in reducing wear. The correct choice depends on various factors. This study analyzes the changes in the composition of three different engine oils (0W30, 5W30, and 5W40) during the generally accepted oil change interval (15,000 km) in gasoline and diesel cars during the post-warranty period. Commercially available low-level biofuel blends (B7 and E10) were used to power test vehicles in a field test. Engine oil samples were taken every 3000 km for more detailed analysis and tested in an accredited laboratory. The contaminants in the engine oil were determined using several testing methods: spectrometric analysis, gas chromatography, etc. Studies have shown that all used cars have an increase in the number of iron particles, an increased concentration of silicon, and also an increase in the number of nickel particles above 12,000 km. Tests also showed a sharp drop of molybdenum anti-friction additives 4.5 times and a gradual increase in fuel concentration for the Opel Insignia over 12,000 km, but over 9000 km, a significant increase in the concentration of chromium particles. Based on this research results, it is preferable to choose a maintenance interval of no more than 12,000 km for cars during the post-warranty period. In this way, the intensity of engine wear can be reduced due to the loss of adequate protective properties of the engine oil.

Lubricating Ability of Protic Ionic Liquids as Additives to a Biodegradable Oil for Aluminum-Steel Contact: Effect of Alkyl Chain Length and Propensity to Hydrogen Bonding

Although aluminum alloys are widely used in the automotive and aerospace industries due to their excellent strength-to-weight ratio and good corrosion resistance, the poor tribological performance and low compatibility of these materials with lubricant anti-wear and anti-friction additives in conventional mineral oils are major limitations. In addition, environmental awareness has increased the need for more environmentally friendly lubricants. Ionic Liquids (ILs) have exhibited significant potential as lubricants and lubricant additives. One of the more interesting properties of ILs is that they can form physically-adsorbed or chemically-reacted layers that reduce friction and wear of the surfaces in contact. Among ILs, Protic Ionic Liquids (PILs) have received more attention recently because of their simple and economic synthesis route. Furthermore, the anions and cations of PILs can be selected to be considered environmentally benign. In this article, the tribological behavior of a family of six PILs are studied as additives to a biodegradable oil (BO), under aluminum-steel contact. Al2024 disks slid against AISI52100 steel balls under a normal load of 3 N and a frequency of 5 Hz at room temperature and using a ball-on-flat reciprocating tribometer. PILs used in this study, were synthesized using two strong acids, with short and long hydrocarbon chains, and three weak bases with different propensities to hydrogen bonds. Results show that, although adding just 1 wt.% of any PIL to BO reduced friction and wear, the alkyl chain length influenced the lubricating ability of these ordered fluids. Wear mechanisms and surface interaction are discussed on the basis of 3D profilometry, SEM-EDX and RAMAN spectroscopy.

An investigation on tribological properties of advanced microwave synthesized molybdenum disulfide as anti-friction additives in commercially available lubricating oils

The frictional stress between opposing contact surfaces will damage the mechanical parts of a machine. An appropriate lubricant can significantly reduce this. Blending nanoadditives with base oil is claimed to be an effective technique to increase the anti-friction qualities of lubricants using nanotechnology. Advanced microwave synthesized molybdenum disulfide (MoS2) anti-friction nanoadditive was employed in various lubricating oils namely fully synthetic, semi-synthetic, mineral, and hydraulic oil to formulate the nanolubricant. X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), energy-dispersive X-ray spectroscopy (EDX), and a physical stability observation test were used to study the nanoadditives (MoS2) physicochemical characteristics. The tribological analysis of the MoS2 nanolubricant was measured using the four-ball tribotester. The coefficient of friction (COF) and average wear scar diameter (WSD) of the anti-friction additives were analyzed. The experimental results revealed improvements in COF and WSD in the range of 7.47–15.81% and 6.57–16.07% after the addition of MoS2 nanoparticles in the various lubricating oils. This study discovered that engine oil with advanced microwave-synthesized MoS2 nanoparticles has a significantly lower COF and WSD than engine oil that is not added with the anti-friction additives.

Synthesis and properties of oil-filled polycaproamide

The effect of antifriction additives on the process of ε-caprolactam anionic polymerization and on the properties of the synthesized samples has been studied. Motor oil, vacuum oil, household lubricating oil and polymethyl-siloxane fluid were used as antifriction additives. It has been shown that the introduction of antifriction additives at the stage of synthesis of oil-filled polycaproamide reduces the rate of anionic polymerization of ε-caprolactam. The influence of oils on the complex of physico-mechanical, thermal and operational properties has also been studied. It was found that the use of oils at the synthesis stage helps to reduce the coefficient of friction of the samples compared with the control sample. The best effect is observed when using 5 7 wt.% of petroleum oils (a decrease of 50 66% compared to the control sample). The water absorption of oil-filled polycaproamide samples containing petroleum oils is also reduced (by 37% compared to the control sample). At the same time, there is a deterioration in the physical and mechanical properties and an increase in oil and petrol absorption.

Tribological analysis of advanced microwave synthesized Molybdenum disulfide (MoS2) as anti-friction additives in diesel engine oil for military vehicles

One of the most important method to reduce friction and wear is lubrication which is important in the automotive industry for energy efficiency, environmental conservation, and carbon reduction. Additionally, incorporating nanoparticles into engine oil lubricants can significantly increase their performance, particularly in terms of tribological properties. Advanced microwave synthesized Molybdenum disulfide (MoS2) anti-friction additive in SAE 20 W50 diesel engine oil was employed to formulate the nanolubricant. Fourier-transform infrared spectroscopy (FTIR) and a physical stability observation test was used to study the nano additives' physicochemical qualities (MoS2). The tribological performance of the MoS2 nanolubricant was measured using the four-ball tribotester. The Coefficient of Friction (COF) and average Wear Scar Diameter (WSD) of the anti-friction additives were analysed through tribological investigations of the wear rate and scar of the worn-out surface on ball bearings. MoS2 based nanolubricant improves COF and WSD by 10.25 % and 10.6 % respectively, as a contrast to the engine oil revealed from the tribological analysis. The current study discovered that the engine oil with advanced microwave synthesized nanoparticles have a significantly lower COF and WSD than engine oil which is not added with the anti-friction additives.

Synthesis, crystal structure, thermal properties of copper(II) acrylate complex with 4′-phenyl-2,2′:6′,2′′-terpyridine and its use in nanomaterials science

The reaction between copper(II) acrylate and 4′-phenyl-2,2′:6′,2″-terpyridine resulted in a new metal-containing monomer 1, which was characterized by elemental analysis, FTIR spectroscopy, and single-crystal X-ray diffraction analysis. Complex 1 crystallizes in triclinic form with space group P-1. The chelate node of complex 1 is close to an ideal tetragonal pyramidal structure and includes three nitrogen atoms of the terpyridine ligand and two oxygen atoms of acrylate fragments. Medium-strong hydrogen bond interactions lead to infinite 1D chains. The kinetic and thermodynamic parameters of the thermolysis process of complex 1 were studied. As a result of thermolysis process, nanomaterials of the Cu@C core-shell type were obtained. The resulting nanomaterials are effective antiwear and antifriction additives for lubricating oils.

Copper(II) Stearate-Based Copper-Containing Nanomaterials as Antifriction Additives to Lubricating Oils

Copper(II) Stearate-Based Copper-Containing Nanomaterials as Antifriction Additives to Lubricating Oils

A Short Review on Polymeric Biomaterials as Additives for Lubricants.

With increasing environmental concerns and the depletion of petroleum resources, the development of lubricant additives from bioresources has attracted much attention recently. In this review, we reported a few polymers and polymer composites that are synthesized from vegetable oils (soybean oil, sunflower oil, rice bran oil, and castor oil) and used as multifunctional additives in the formulation of eco-friendly lubricant compositions. We mentioned the preparation of vegetable oil-based homo- and copolymers and their characterization by different spectral techniques (FTIR/NMR). The average molecular weights of the polymers are determined by gel permeation chromatography (GPC). Performance evaluations of the polymeric materials mainly as a viscosity index improver (VII), pour point depressant (PPD), and most importantly antifriction additives when blended with lubricating base oils are indicated. Standard ASTM methods have been applied to evaluate their performances. The findings have shown that all the additives discussed are non-toxic, biodegradable, and showed excellent performances compared to commercial petroleum-based additives.

Improvement of the Tribological Properties of Polyurea Lubricants by the Use of Functional Additives

The effect of antifriction additives based on dialkyldithiophosphoric acid and molybdenum-containing friction modifiers (A-22, A-23, A-24, DF-11, PAF-4, TEF-3, ADTF ) on the tribological characteristics of polyurea lubricating greases based on petroleum and synthetic oils is discussed. The dependence of the tribological characteristics of polyurea plastic greases on the nature, the concentration of the additive (1-3 wt. %), and the dispersion medium was studied. The antiwear and extreme pressure characteristics were determined by three well-known standard methods: ChMT-1 four ball wear tester; Brugger tribometer; KT-2 four ball tester.

Copper-Containing Nanomaterials Derived from Copper(II) Laurate as Antifriction Additives for Oil Lubricants

In the present study, an easily accessible method for obtaining copper-containing tribological nanomaterials by thermolysis of copper(II) laurate at 300 °C was developed. The obtained nanoparticles were studied using X-ray diffraction, atomic force microscopy, and sedimentation analysis. The composition of nanoparticles and the size of crystallites are shown to depend on the thermolysis time. The tribological characteristics of copper-containing nanomaterials derived from copper(II) laurate were analyzed as additives to liquid paraffin using a pin-on-disc tribometer (additive concentration 0.025–0.2%, normal loads 49 and 96 N, rotation speed 200 rpm). The optimal concentration of nanomaterials at which the coefficient of friction is the lowest is determined. An increase in load to 98 N leads to a decrease in the coefficient of friction. The mechanism of friction in the presence of the studied nanolubricants is discussed.

Улучшение трибологических свойств полимочевинных смазок за счет применения функциональных присадок

This work describes antifriction additives based on dialkyldithiophosphoric acid and molybdenum-containing friction modifiers and its influence on lubricating greases prepared with petroleum and synthetic oils tribological properties. The dependence of tribological properties of polyurea greases tribological properties on the nature, concentration of the additive (1–3 wt%) and the dispersion medium has been studied. Evaluation of antiwear and extreme pressure properties was carried out by three well-known standardized methods – FBW (four ball wear test system) and KT-2 and also using the Brugger tribometer.

INFLUENCE OF FRICTION REGIMES ON THE TRIBOTECHNICAL PROPERTIES OF COMPOSITES BASED ON PTFE AND CARBON FIBERS

The paper presents the results of tribotechnical tests of polymer composite materials based on polytetrafluoroethylene (PTFE) and carbon fibrous activated material UVIS-AK-P (SPC UVIKOM LLC) depending on the contact pressure in dry and boundary friction modes in various oils. I-20A industrial oil, Siboil TAD-17u transmission oil, and Rosneft Gidrotec HLP 46 hydraulic oil were used as liquid lubricants for the friction of polymeric materials. For tribotesting, a polymer composite with a content of 5 % wt. UVIS-AK-P, obtained using sequential mixing of filler with PTFE and the technology of joint activation of components in a planetary mill, is the most wear-resistant material according to the results of previous studies. It has been established that despite the heavy wear at increased bearing pressure during dry friction, unfilled PTFE does not undergo plastic deformation and maintains a low coefficient of friction practically unchanged. It has been found that the friction coefficient passes through a minimum during dry friction of a composite with CF at a load of 350 N. It is associated with the transition of the elastic contact of the interacting elements of the surfaces of the metal-polymer tribosystem to the plastic one with increasing load. During friction of PTFE in a lubricating oil environment, a significant decrease in mass wear, friction coefficient and temperature in the contact zone are observed due to the formation of secondary structures on the friction surfaces and the significant flexibility of PTFE. This increases the actual area of the tribocontact, which reduces the value of real normal contact stresses. During friction of polymer composite materials in the environment of lubricating oils, a decrease in the friction coefficient and the area of the friction track by 1.7-2.7 times was recorded as well. Deformations, groove formation and mass wear were not observed. It has been revealed that the greatest effect of increasing the wear resistance and permissible friction load and lowering the temperature in the friction zone of PTFE and composite is observed when using Siboil TAD-17u transmission oil. This is due to the presence of special antifriction additives in this oil brand and a decrease in the actual contact of the working surface of the polymer material with the lubricant, which helps to reduce the intensity of the destructive process in the surface layer while contacting with the lubricant.

Lubricating Oils Obtained via Modifying Magnetic Nanofluids

A novel approach to improving the lubricating properties of magnetic nanofluids based on polyethylsiloxane operated in a mode of boundary friction based on their modification using antifriction additives has been studied. It has been established that the greatest tribotechnical effect can be achieved via introducing chlorine-containing antiscuff additives to magnetic nanofluids. Recommendations are given concerning the practical use of the obtained magnetic lubricating compositions.

ОЦЕНКА ВЛИЯНИЯ АНТИФРИКЦИОННОЙ ПРИСАДКИ НА ЭКОНОМИЧЕСКИЕ, МОЩНОСТНЫЕ И ЭКОЛОГИЧЕСКИЕ ПОКАЗАТЕЛИ ДВИГАТЕЛЕЙ ВНУТРЕННЕГО СГОРАНИЯ

To determine eff ectiveness and feasibility of using an antifriction additive, the authors carried out comparative bench tests of an internal combustion engine VAZ-11194 No. 000094 of environmental class 5, with and without using an antifriction additive to Lukoil Genesis 5W-30 oil. The studies were carried out in accordance with GOST 14846 “Automotive Engines, Bench Test Methods”, UN Regulation No. 49 (emissions of carbon monoxide, hydrocarbons, nitrogen oxides with exhaust gases) and UN Regulation No.85 (performance indicators). During the tests, harmful substances with exhaust gases (CO, CH, NOx) emissions,engine power indicators and fuel consumption were evaluated. The tests were carried out according to presented method after 5, 50 and 100 hours of engine operation. The test results recorded an increase in power by 4.1%, in engine torque by 3.5…4.0% with a decrease in specifi c fuel consumption by 6…7% after 100 hours of engine operation with the use of an antifriction additive in engine oil. During the test period, harmful substances concentration in engine exhaust gases decreased: CO to 21.6%, CH to 18.3%, and NOx to 27.6%. A conclusion has been formulated on the eff ectiveness of using antifriction additives in terms of improving environmental, economic and power indicators of an internal combustion engine

Определение влияния антифрикционных компонентов на трибологические свойства резьбовых покрытий

Within the development of a material, which forms a multifunctional coating on the threaded surface of tubes and joints, the authors identified the requirements specified for a coating. One of the main requirements is the possibility to perform the repetitive screwing of threaded connections without thread damage. The necessity to obtain a high level of anti-friction properties of a coating aroused the study of the influence of anti-friction additives of various effect on the tribological properties of a coating: the decrease in the friction coefficient of conjugate surfaces and ensuring the abrasion resistance of a coating. To identify the influence of anti-friction additives of various effects on the functional properties of a coating, the authors carried out the comparative laboratory tests of thread coatings containing various anti-friction additives under the sliding friction at the reciprocation according to the “fixed plate - finger” scheme. As the anti-friction components, the authors used graphite, molybdenum disulfide, and polytetrafluoroethylene (PTFE), which have different anti-friction properties. The tests were carried out for the coatings containing the complex of additives as well: graphite - PTFE, molybdenum disulfide - PTFE. The authors evaluated the tribological properties of the resulting coatings according to their friction coefficient value and abrasion resistance. To select optimum concentrations of anti-friction components, the authors tested the materials containing the complex of additives with different concentrations of graphite and molybdenum disulfide. To confirm the results of laboratory tests, the authors carried out full-scale tests in the factory environment when applying the selected coating to the threaded surface of a tube and a joint. The research identified the positive effect of the multipurpose utilization of anti-friction components. The authors determined the systems of anti-friction components (graphite - PTFE and molybdenum disulfide - PTFE) and their optimum concentrations (graphite and molybdenum disulfide - 8 wt. %, PTFE - 6 wt. %) in the thread coating material. The full-scale tests in the factory environment confirmed the results of laboratory tests.

The Impact of Two-Layer Lubrication Parameters on the Service Life of Railway Rails

The prerequisites, basic hypotheses and sequence of creation of a mathematical model for estimation of service life of railway rails in conditions of two-layer lubrication are given in the article. The created mathematical model is presented in the final form. The model takes into account the geometry of the wheel-rail contact, the initial and constant surface roughness, actual loads on the rail, speed of the rolling stock, strength characteristics of steels and the antifriction additive, as well as the basic parameters of two-layer lubrication. The main parameters of lubrication include the concentration of solid antifriction additives in oil which is sufficient to fill irregularities of the contact surface; the boundary molecular oil film thickness. The results of calculations using the developed mathematical model are presented. The performed calculations reveal the positive effect of the parameters of a two-layer lubricant on the resource of rails. The anti-wear effect of the lubricant increases as the concentration of graphite in the oil increases and the weight of the carriage decreases. Based on the performed calculations, conclusions and recommendations were obtained regarding further experimental verification of the mathematical model, as well as the influence of the parameters of two-layer spray lubrication on wear and service life of transport rails.

Correlation between Lube Oil HTHS and Techno-Economic Performance and Service Life of a Reciprocating Engine

This paper discusses the effect of lube oil high-temperature viscosity on performance indices of high-powered automotive engines (e.g., power, fuel economy and wear rate of friction pairs). Such engines are generally prone to departure from hydrodynamic friction mode in friction pairs, caused by high mechanical load and high lube oil temperature. In this case friction horsepower will depend not only on oil viscosity parameters, but also on properties of anti-wear and anti-friction additives, if any. Moreover, spread in high-temperature viscosity of motor oils belonging to the same SAE group may be great enough. This paper furnishes evidence of existence of optimum high-temperature viscosity level, at which fuel economy reaches its maximum. Dependence of optimum viscosity on engine power conditions is revealed. One of the tasks of this work is examination of how high-temperature viscosity (HTHS) of modern all-synthetic motor oils, belonging to various viscosity classes, correlates with friction and wear characteristics of a high-speed motorcar engine.

Tribo-Investigations on Oils With Dispersants and Hexagonal Boron Nitride Particles

A dispersant is almost an unavoidable additive in engine oils since it helps to keep the carbonaceous particles in a suspended form. Dispersants can be multifunctional and can therefore interfere with the functions of other additives either synergistically or antagonistically. The present work investigated the influence of four dispersants (with and without particles of hexagonal boron nitride (hBN) on selected lubrication-related properties of the oils using four ball tester. Particles of hBN, though known as effective anti-wear (AW) and anti-friction (AF) additives, did not prove effective in oil in the presence of dispersants. On the other hand, it proved to be a good extreme pressure (EP) additive by showing 27% improvement in weld load (WL). Worn surfaces were examined using scanning electron microscopy (SEM), energy dispersion X-ray analysis (EDAX), and Raman spectroscopy.

Predicting the limiting strength of chaotically reinforced polymer composites with dispersed antifrictional additives

The limiting strength of antifrictional polymer composites in uniaxial compression is investigated as a function of their components, by numerical modeling.