Anti-wear Properties Research Articles

Investigate on the dry friction tribological behaviors and mechanism of carbon quantum dot/polyimide composites coating

The comprehensive utilization of biomass resources is to be prepared into functional nanomaterial. This paper prepared carbon quantum dots (CQDs) using citric acid. A new CQDs/polyimide composites (CQDs/PI) coating fabricated on the surface of steel disks, has been widely used in bearing sleeve material or coatings in marine equipment parts and aerospace industries. Tribological properties of coating materials were investigated at different loads and reciprocating speeds of 10 mm/s under dry sliding conditions using a UMT-2 tribometer and compared to those of commercial MoS2 particles in PI composites. Scanning electron microscopy accompanied by energy spectroscopy (SEM/EDS) and 3D laser scanning microscopy were used to characterize the morphologies of the abrasion marks to clarify the tribological mechanisms. Results show that different levels of CQDs can improve composite coatings' anti-wear and friction reduction properties. The tribological mechanisms of CQDs were attributed to the enhancement of the hardness of the polyimide coatings by the CQDs and the formation of a transfer film on the surface of the ceramic balls during the friction process reducing the direct contact at the friction sub-interface.1

Synthesis and tribological properties of the novel tubular MoS2/GR nanocomposite

This study used a simple one-step hydrothermal method to synthesize the MoS2/GR composites with a new morphology composed of graphene nanotubes and ultra-thin molybdenum disulfide with the help of sodium chloride. The composites were characterized by XRD, XPS, SEM, TEM, and a series of characterization methods. Meanwhile, the tribological properties of the composites were studied. The results show that the addition of 1% MoS2/GR composite nanotubes has excellent tribological properties. In addition, the structure and excellent tribological properties of MoS2-C- nanocomposite lubrication materials will be conducive to designing new nanomaterials with 2D/3D structures, enhancing the anti-friction and anti-wear properties, and expanding their practical applications in industrial and agricultural fields.

Study of the influence of pollution particles of 5 мkм and less on the anti-wear properties of the working fluids of hydraulic drives of construction and road machinery

Problem. An analysis of the impact of contamination of the working fluid on the state of the hydraulic equipment elements of construction and road machines, the efficiency of their operation, and also the use of the coefficient of anti-wear properties to determine the service life of working fluids is presented. The equation of the dependence of the wear rate of hydraulic equipment elements on the coefficient was obtained. Operational tests of the GR165 motor grader were also carried out, which showed that the service life of the Hydro HV 46 working fluid according to the coefficient of anti-wear properties is approximately 1184 machine hours. Methodology. In the process of studying the state of the matter, the method of analysis was used, and in theoretical studies – the analytical method, which is based on the theory of interaction of working bodies with the developed environment, as well as the provisions of the theory of reliability, probability and mathematical statistics. Results. The research results showed that coefficient Kj of anti-wear properties can be the only integral indicator of the quality of working fluids and determine their service life in hydraulic drives of Construction machines. Originality. The equation was obtained for the rate of wear, taking into account the interaction of charged particles of wear with friction surfaces. For the stationary friction mode, the equation of the balance of the contamination particles that are part of the working fluids of the hydraulic actuators and the rate of wear of friction vapor were obtained. The use of KJ coefficient as an indicator of working fluids of hydraulic drives of construction machines is presented. Practical value. The research results showed that the coefficient Kj of anti-wear properties can be the only integral indicator of the quality of working fluids and determine their service life in hydraulic drives of Construction machines.

Strengthening of friction surfaces by using geomodifiers based on serpentines from the Dashukivka deposit

The object of research is the process of improving the tribological characteristics of friction joints, in particular anti-wear and anti-burr properties. There is a practice of using serpentines, so-called "friction geomodifiers" (FGM), as special repair and restoration additives. Their use leads to a decrease in the coefficient of friction and temperatures in the contact zone; an increase in the mass of parts is observed, which indicates the restoration of worn surfaces. The mechanism of formation of new structures is still unclear. There are hypotheses that severe friction conditions initiate micrometallurgical processes at the atomic-crystalline level, as a result of which modified layers with unique tribological characteristics are formed on the surfaces. A comparative analysis of the main indicators of serpentines of the Dashukivka deposit in terms of chemical composition and structure showed their correspondence to widely known analogs but they were never used in such a capacity. According to the results of the tests, the additives have shown their effectiveness as geomodifiers of friction. Addition of 4 % serpentine to the lubricating composition based on I-20 A oil reduced the wear rate by 2–3 times, the friction moment by 15 %, compared to I-20 A without additives. An increase in surface microhardness was observed, from 6 GPa for the basic variant to 10 GPa, for the variant with FGM additives. It has been established that the use is most effective for heavily loaded friction pairs (ship fittings, hatch closures, etc.) as it increases the clamping load (from 600 to 1400 N for a pair of steel 45/ShKh15); with increasing load, the coefficient of friction and the rate of wear decrease. The results confirm the need to expand research into this area to solve the complex problem of increasing the reliability of tribojunctions. Keywords: repair and restoration technologies, friction geomodifiers, serpentine, heavily loaded friction pairs

Tribo-Dependent Photoluminescent Behavior of Oleylamine-Modified AgInS2 and AgInS2-ZnS Nanoparticles as Lubricant Additives

The content of Cu2+ in lubricants is an essential indicator for determining the quality of the lubricant and predicting mechanical failure. Finding an effective and sensitive method for detecting Cu2+ in lubricants is of great importance in oil monitoring. In this work, AgInS2 (AIS) and AgInS2-ZnS (ZAIS) nanoparticles (NPs) were synthesized by a simple one-step approach via in-situ surface modification by oleylamine. The as-synthesized AIS and ZAIS NPs exhibit good dispersion stability in various apolar media. The photoluminescence (PL) of AIS and ZAIS NPs as lubricating additives could reflect and monitor the lubrication state of steel-copper pairs due to the quenching effect of Cu2+ from the friction process. With an optimum concentration of 0.5 wt% in paraffin oil, the friction coefficient of the AIS and ZAIS NPs at 100 N was decreased by 56.8 and 52.1% for steel-steel contacts, respectively. ZAIS was observed to be more effective than AIS in improving anti-wear (AW) and extreme pressure (EP) properties, with a load-bearing capacity of up to 1100 N. Characterization of the wear tracks by SEM and XPS indicates that a tribofilm composed of metal sulfides and oxides was formed during the lubricating process. This work not only reveals AIS and ZAIS NPs as a new class of promising candidates for lubricating additives but also unveils their potential for monitoring lubricant conditions and exploring lubricant service life.

Evaluation results of the tribological properties of aviation oils for aircraft engines

The development of modern heat-stressed aircraft engines is a complex process based on the advanced achievements of various branches of science and technology, including chemmotology. Each new generation of aircraft engines imposes stricter requirements on the quality of the aviation oils used to ensure the reliable operation, including engine oil systems, rotor bearings and other components. One of the important factors in reducing friction and wear-out of modern gas turbine engines is the use of high-quality oils with a high level of anti-wear and anti-friction properties which allow engines to operate under various relubrication intervals. In the domestic regulatory and technical documentation, the anti-wear properties of aviation oils are evaluated using a four-ball friction machine according to GOST 9490, and the anti-friction properties are not taken into account. The specified friction machine has a variety of disadvantages. In this regard, the authors evaluated the anti-wear and anti-friction properties of domestic aviation oils using a versatile vibro-tribometer which allows for the operational properties of oils to be researched under the modes that are the most characteristic for the actual operation of aircraft engines compared with parameters of oil tests by a four-ball friction machine. Unlike the four-ball friction machine, the vibro-tribometer design implements a contact - interaction scheme in a “ball-plate plane” friction pair. At the same time, a thermal chamber is installed on this application that provides constant heating of the friction pair and the tested lubricating oils to the required temperature (from 0 to 150 ℃). It has been found that IPM-10 aviation oil possesses the best anti-wear and anti-friction properties, and with an increase in the tested oil temperature, a proportional increase in wear-out in the “ball-plate plane” friction pair occurs.

On fabrication of acrylonitrile butadiene styrene-zirconium oxide composite feedstock for 3D printing-based rapid tooling applications

The 3D-printed rapid tools are being used in finishing operations such as drilling, milling, broaching, roller burnishing, and other finishing operations that need anti-wear plastic composite materials. Zirconium oxide (ZrO2) is one of the ceramic materials which is highly appreciated due to its anti-wear properties. This study aims to develop the ZrO2 ceramic particles reinforced acrylonitrile butadiene styrene (ABS) thermoplastic composite feedstock filaments for 3D printing of rapid tools. In the first stage, the multiple numbers (as per Taguchi L9 orthogonal array (OA)) of ABS-ZrO2 feedstock filaments were developed by varying the loading of ZrO2 in ABS matrix (2 wt.%, 4 wt.%, and 6 wt.%), processing temperature (200, 205 and 210°C), and rotation speed of screw (4, 6 and 8 RPM). The optimum setting obtained for manufacturing ABS-ZrO2 composite feedstock filaments is the combination of 2% ZrO2 loading, 205°C processing temperature, and 6 RPM screw speed. In the next stage, fused filament fabrication (FFF) based 3D printing has been used to prepare the rapid tools. The wear test performed for 3D printed ABS-ZrO2 composites rapid tools shows only .62% weight loss which is lower as compared to virgin ABS (.91% weight loss). The results of the study are supported by fracture analysis, morphology, and mechanical properties.

Resistant Properties of Lubricating Materials with Fullerene Nanoadditives

The purpose of this article is to study the possibility of using fullerene additives and their effect on the antiwear properties of aviation mineral and synthetic oils. The method of increasing the anti-wear properties of mineral MK-8p and synthetic Mobil Jet Oil 254 oil for turbojet aircraft engines by adding fullerene additive C60 is considered. It has been shown that the anti-wear properties of synthetic Mobil Jet Oil 254 oil for turbojet aircraft engines exceed MK-8p mineral oil by more than 10%. Increasing the concentration of fullerene additive in oils increases the wear resistance of conjugated surfaces. It was established that the increase in the concentration of the fullerene additive in oils shifts the critical load to higher values for both mineral and synthetic oils. The intensity of this growth is observed in mineral oil to a greater extent than in synthetic oil. The use of fullerenes as an anti-wear additive to oils for turbojet engines is proposed, which improves anti-friction properties and reduces the wear of parts of machines and mechanisms. Scientific progress is determined mainly by experimental research, the conduct of which in this direction is quite relevant.

Review of aspects of processing and use of waste cooking oils as effective lubricants

In connection with environmental pollution and the depletion of oil reserves, biologically based lubricants have received great interest as a replacement for mineral oil-based lubricants. Biolubricants have a number of advantages over mineral lubricants, including high biodegradability, low toxicity, lubricating properties and minimal environmental impact. The presented review describes the main characteristics and properties of biological lubricants, various vegetable oils, which are used as raw materials for the production of biolubricant materials. The physicochemical properties of biological lubricants were analyzed from the point of view of improvement. The technological processes used for the chemical modification of vegetable oils, ensuring the lubricity and anti-wear properties of the obtained biolubricants are determined. Various additives used to improve the properties of biolubricants are also recommended. This review material will provide researchers and practitioners with additional information on the practice of using biolubricants.

A Method for Mathematical Modeling of Hydrodynamic Friction of Plunger Pairs with Consideration of Microgeometry

The fuel injection system heavily relies on the high-pressure fuel pump, which plays a critical role in its overall performance. The fuel pump plunger is subjected to high levels of stress and experiences irregular lubrication during dynamic loads, causing premature wear. In the industrial sector, laser surface micro-texturing has been utilized to reduce friction and enhance anti-wear properties, and its positive impact has been supported by both theoretical and experimental evidence. This article presents a method for determining the hydromechanical characteristics of plunger pairs under conditions of hydrodynamic friction. The microgeometry of friction surfaces was taken into account through the cavitation effect of the lubricating fluid, described by the modified Reynolds equation. Software was developed according to the proposed method. The developed software can be used to analyze the contacting surfaces of plunger pairs and evaluate their tribotechnical characteristics based on the microgeometry parameters of the friction surfaces. The article also discusses the impact of the microgeometry parameters on the quality criteria of the hydromechanical characteristics of the plunger pairs. Computational examples are given for the analysis of contacting surfaces of plunger pairs separated by a lubrication layer. The technical characteristics are evaluated depending on the parameters of the microgeometry of the roughness of the friction surfaces. The influence of the microgeometry parameters on the quality criteria of the hydromechanical characteristics of the plunger pairs is presented.

Improving the adsorption strength of amine-based organic additives for reducing wear

Organic additives can mitigate wear significantly by adsorbing on rubbing steel surfaces in mechanical contacts. Our aim is to design additives that maximize the adsorption strength and the surface coverage for an optimal wear reduction. Molecular simulations are employed and combined with cross-pin wear tests to investigate anti-wear properties of N,N - Bis(4-aminobutyl) oleylamine (b4ab-OA) taken as a promising additive. Results are compared with oleylamine (OA). The stronger energy of adsorption computed in molecular simulations for b4ab-OA correlates well with experiments that showed both reduced wear and a fast formation of the adsorbed film on rubbing surfaces. Overall, results suggest that the b4ab-OA additive is a better alternative than OA for protecting surfaces from wear.

Differentiated SnSb grain size distribution for improved tribological properties of Babbitt alloy

PurposeThe grain size and grain distribution mode have a significant impact on the tribological properties of Babbitt alloy. The purpose of this paper is to study the effect of differentiated SnSb grain size distribution on the improvement of tribological properties of Babbitt alloy.Design/methodology/approachBabbitt (marked by babbitt-cr), with a differentiated SnSb grain size distribution, was fabricated using a selective zone laser surface treatment. Bare Babbitt with coarse SnSb grain was marked as babbitt-c, and Babbitt with refined SnSb grain was marked as babbitt-r. The microstructure, microhardness and wettability of specimens were tested. The tribological properties of babbitt-c, babbitt-r and babbitt-cr were evaluated under dry and lubricated conditions.FindingsThe microstructure transforms from single coarse SnSb grain distribution or single refined SnSb grain distribution to differentiated SnSb grain size distribution, as a result of selective zone laser surface treatment. Among three specimens of microhardness, babbitt-cr showed the highest microhardness. The lipophilicity property of babbitt-cr was better compared to babbitt-c. A mixture of coarse and refined grain is beneficial to improve the tribological properties of Babbitt alloy under dry condition. Furthermore, compared with babbitt-c, the wear resistance of babbitt-cr was enhanced under lubricated condition. However, the anti-wear property of babbitt-cr was not significantly improved relative to babbitt-r with an increase in the loads.Originality/valueThe study demonstrates that modulated different grain size alternating distribution modes can improve the tribological properties of Babbitt alloy.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2022-0259/

Preparation and properties of graphene composite lubricants additive used for cylinder liner in marine diesel burning low sulfur fuel oil

In recent years, abnormal wear issues have emerged in cylinder liner-piston rings (CL-PRs) in marine diesels that burn low-sulfur fuel oils (LSFO). To address this issue, a graphene-attapulgite composite additive was prepared and characterized as detailed in this report. Then, the tribological properties and corrosion resistance of this graphene-attapulgite were investigated when it was used at various concentrations as a multifunctional composite lubricant additive in simulated LSFO lubrication conditions. It was found that the appropriate concentration of the additive in a lubricant produced excellent anti-friction and anti-wear properties. This was when the additive was at 0.25 wt% concentration in normal lubricating conditions, where the friction coefficient and wear mass loss were reduced by 22.7% and 44.1%, respectively. Additionally, the impermeability of the graphene additive was found to improve the corrosion resistance of the lubricant. These findings revealed the mechanism of the graphene-attapulgite additive for friction reduction and corrosion resistance of cylinder liner in simulated LSFO lubrication conditions, which provided an inhibition method to prevent abnormal wear of cylinder liner in marine diesel burning LSFO.

Green synthesis of trimethylolpropane triisostearate and triisooleate for usage as bio-lubricants

Two methyl-branched triesters, trimethylolpropane-triisostearate (TMP-ISA) and trimethylolpropane-triisooleate (TMP-IOA) have been synthesized via esterification of trimethylolpropane with isostearic-acid and isooleic-acid, respectively. Isostearic-acid and isooleic-acid have been previously produced through the skeletal-isomerization reaction of naturally derived oleic acid using a reusable zeolite catalyst. TMP-ISA and TMP-IOA are characterized by FTIR NMR, GC-MS, and LC-MS. Physicochemical and tribological analysis reveal that TMP-ISA and TMP-IOA exhibit higher oxidative stability, viscosity index, anti-wear property, and better cold flow properties when compared to high-oleic sunflower oil or polyalphaolefin, a common lubricant base oil. Lubricant property analysis of blends of TMP-ISA or TMP-IOA with high-oleic sunflower oil or polyalphaolefin demonstrates their miscibility and potential applications as biolubricants. Upon commercialization, these developed bio-based esters have the potential to reduce the existing reliance on non-renewable petroleum based lubricants. Practical applicationMethyl-branched triesters with trimethylolpropane backbone exhibit promising physicochemical and tribological properties to be used as bioingredients in bioproducts.

Effect of polymer additives on the tribological performance of soybean oil

PurposeThis study aims to investigate the behavior of vegetable oil with two additives. Base oil’s tribological qualities can be improved with the help of several additions. In the present investigation, soybean oil is served as the foundational oil due to its eco-friendliness and status as a vegetable oil with two additives, named polytetrafluoroethylene (PTFE) and molybdenum disulfide (MoS2).Design/methodology/approachAs additives, PTFE and MoS2 are used; PTFE is renowned for its anti-friction (AF) properties, while MoS2 is a solid lubricant with anti-wear (AW) properties. This investigation examines the synergistic impact of AF and AW additions in vegetable oil. The lubricity of the base oil is measured by using a four-ball tester, and the wear properties of the oil at different additive amounts are determined by using a universal tribometer.FindingsPTFE (at 5 Wt.%) and MoS2 (at 1 Wt.%) were found to improve the tribological performance of the base oil. The weld load is significantly increased when 5 Wt.% of PTFE + MoS2 is added to the base oil.Originality/valueA better tribological characteristic can be achieved by combining additives that amount to less than 1% of the base oil. In experiments with highly concentrated MoS2, the adequate pressure improved dramatically, but the lubricant’s tribological characteristics did not.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2022-0321/

Simultaneously improving mechanical, thermal, and anti-wear properties of Ti alloys using 3D-networked graphene as reinforcement

The simultaneous improvement of mechanical and functional properties of Ti alloys is of considerable significance for their diverse applications and service life. Incorporating graphene with Ti is hoping to realize that, however, it is challenging to achieve the improvement because of the poor chemical stability of carbon/Ti systems. This challenge becomes particularly significant when using high carbon-content reinforcements, as the reinforcement agglomeration is considered to adversely affect composite performances. In this work, an efficient powder metallurgy method was developed to fabricate titanium matrix composites reinforced by a high content of graphene nanosheets (GNSs). Quasi-continuous GNSs were arranged in a 3D network and were surrounded by in-situ TiC. The results revealed that the load-transfer and solid-solution strengthening factors contributed to the high mechanical strength of the composites. Moreover, the GNS networks conduced to the improvement of thermal conduction, reduced the total weight, and enhanced the anti-wear performance of the composites via self-lubrication. Furthermore, the proposed approach can be applied to other carbon/metal composites for achieving significant improvements in their performance.

Gradient-distributed ZTAp-VCp/Fe45 as new anti-wear composite material and its bonding properties during composite casting

Abstract In this article, gradient-distributed VCp-ZTAp/Fe45 composites were prepared by vacuum sintering, and three-body abrasive wear experiments were carried out to investigate its anti-wear performance. The composite casting of VCp-ZTAp/Fe45 was investigated by using the finite element method and experiments, and the bonding between the Fe45 substrate and 35SiMnCrMoNi steel was fully investigated. Results show the in situ formation of VCp in the VCp-ZTAp/Fe45 composite matrix during vacuum sintering. The anti-wear property of the VCp-ZTAp/Fe45 composite is ca. 7 times that of Hardox450 and NM450 and ca. 8 times of 30SiMn. There forms a solid metallurgical bonding between the Fe45 matrix of VCp-ZTAp/Fe45 and 35SiMnCrMoNi steel, with a ca. 80 μm thickness of the bonding area during the composite casting.

The effect of nanolubrication on wear and friction resistance between sliding surfaces

PurposeStudies on this topic have shown the remarkable lubricating properties, viz. friction-reducing and anti-wear, of certain nanoparticles. This makes them potential candidates for replacing the lubrication additives currently used in automobile lubricants, especially because the latter is known to be pollutants and less efficient in some specific conditions. This has not gone unnoticed to professionals in the sector, including those commercializing these additives, the oil companies and the car industry, all of whom are following this burgeoning research area with keen interest. All of them are faced with the problem of providing lubricants that meet the needs of the technological evolution of engines while respecting ever-stricter environmental norms.Design/methodology/approachThe impact of copper oxide (CuO) and zinc oxide (ZnO) nanoparticles on the tribological properties of the SAE-40 pure diesel oil is studied in this paper. The two nanoparticles are not oxide or deteriorate with the base oil. The average size of CuO and ZnO nanoparticles is 40 and 20 nm, respectively. Nanoparticle concentrations of 0.1 Wt.%, 0.2 Wt.%, 0.3 Wt.%, 0.4 Wt.% and 0.5 Wt.% are tested using a pin-on-disk tribometer to evaluate their impact on friction and wear. The test is carried out at different loads and rotating speeds of 58.86 N and 300 rpm, 39.24 N and 500 rpm and 78.48 N and 900 rpm at room temperature, respectively.FindingsThe obtained results of the nanolubricants are compared with those of pure diesel oil in terms of % improvement in tribological properties. However, it is observed that an increase in the nanoparticle concentrations does not guarantee to enhance the tribological properties. Similarly, increasing the applied load and the rotating speed does not lead to improving the anti-friction and anti-wear properties. The results obtained revealed that the optimal improvements in the anti-friction and anti-wear properties of the pure oil are 69% and 77% when CuO nanoparticle concentrations of 0.3 Wt.% and the ZnO nanoparticle concentrations of 0.1 Wt.% are used, where the applied load and rotating speed are 39.24 N and 500 rpm, respectively. It has also been noticed that the CuO nanolubricants have a significant impact on the anti-friction property compared with ZnO nanolubricants.Originality/valueAll these nanoparticles have been the subject of detailed investigation in this research and many key issues have been tackled, such as the conditions leading to these properties, the lubrication mechanisms coming into play, the influence of parameters such as size, structure and morphology of the nanoparticles on their tribological properties/lubrication mechanisms and the interactions between the particles and the lubricant co-additives. To answer such questions, state-of-the-art characterization techniques are required, often in situ, and sometimes an extremely complex set up. Some of these can even visualize the behavior of a nanoparticle in real time during a tribological test. The research on this topic has given a good understanding of the way these nanoparticles behave, and we can now identify the key parameters to be adjusted when optimizing their lubrication properties.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-08-2022-0234/

Tuning the interfacial behavior of extreme pressure lubrication by stearic acid-modified TiO2 nanoparticles

The development of high-performance lubricants under extreme pressure (EP) is of great significance for reducing energy waste and protecting ecology in heavy industries such as aerospace, large machinery, and so on. Sulfurized isobutylene (SIB) has been explored as one of the most effective EP additives for oil-based lubricants and delivered promising friction-reducing performance. However, the excessive corrosion caused by SIB on the metal surface seriously reduces the instrument’s lifetime and hinders its extensive practical application. Herein, we develop stearic acid-modified TiO2 nanoparticles (SA-TiO2) as a lubricant additive to improve the EP lubrication performance of obtained composite lubricant (CL). During EP friction, the SA-TiO2 can tune the interfacial structure of tribopair and form a high-strength nano-ceramic film to improve tribological performance. Meanwhile, the SA-TiO2 can also compensate for the high wear caused by SIB, thus significantly enhancing the antiwear, friction reduction, and EP properties by 27%, 20%, and 25%, respectively, when compared with the traditional lubricant (TL) obtained by only SIB. Benefiting from the above synergistic effects, the CL can significantly lower the SIB contents while maintaining high EP performance (4900 N weld load). These findings demonstrate a promising eco-friendly lubricant and provide new insights into the mechanism study for EP lubrication.

Study on anti-wear and friction-reducing compounding additives in lithium greases

PurposeThis paper aims to determine a suitable anti-wear and friction-reducing compounding additive for lithium greases (LG) by investigating the effects of three single additives potassium borate (PB), zinc dialkyl dithiophosphate and molybdenum dialkyl dithiophosphate (MoDDP) and two compound additives on the friction, wear and extreme pressure properties of LG.Design/methodology/approachThe effects of the above five additives on the friction, wear and extreme pressure properties of LG were investigated using an SRV-5 friction tester. An X-ray photoelectron spectrometer was used to analyze the various elements presented on the wear surface as well as the types of compounds.FindingsThe compound additive suitable for grease consists of PB and MoDDP, which have excellent friction reduction, anti-wear and extreme pressure properties. And a boundary protection film consisting of oxide and MoS2 is formed on the friction surface, thus improving the friction reduction and anti-wear performance of the grease.Originality/valueThis study can improve the anti-wear and friction-reduction performance of greases, which is of great importance in the field of industrial lubrication. The results of this paper are expected to be useful to researchers and academics of grease.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-11-2022-0350/