Wear Scar Surface Research Articles

Mechanical properties of CoCrFeNi-X (X = Ti,Sn) high entropy alloy and tribological properties in simulated seawater environment

Five multimajor element CoCrFeNi-X(X = Ti,Sn) high entropy alloys (HEA) were prepared by vacuum hot press sintering. The phase composition, mechanical properties and tribological properties of CoCrFeNi-X(X = Ti,Sn) alloys in simulated seawater were investigated. The phase structure of CoCrFeNiTi high-entropy alloy is solid solution FCC phase, R phase, σ phase, and Laves phase. But after addition Sn elements, the phase structure become the FCC phase and Ni-Sn solid solution phase. CoCrFeNiTi alloy has lower density (7.17 g/cm3) and higher hardness (750 HV) than that of CoCrFeNiSn. The compressive yield strength of CoCrFeNiTi HEA is better than CoCrFeNiSn HEA. The CoCrFeNiSn high-entropy alloys showed lower wear rates. The main reason is that SnO2 is generated on the wear scar surface, which has good wetting and corrosion inhibition effects, so CoCrFeNiSn HEA shows better wear resistance in simulated seawater. The main wear mechanism of the CoCrFeNiSn HEA is abrasive wear, oxidative wear, exfoliation wear and corrosive wear.

Tribological behaviour of Fe-based amorphous coating at elevated temperatures

Fe-based amorphous coatings (AMCs) were deposited using detonation spraying technology to investigate its performance in high-temperature wear conditions. The results indicate that the detonation-sprayed Fe-based AMC possesses a dense structure, low porosity, high amorphous phase content. At 300 °C, the coating has a maximum wear rate of 6.53 × 10−6 mm3 N−1 m−1, which is almost three times that at room temperature. The main wear mechanisms are oxidative wear, accompanied by fatigue stripping wear and adhesive wear. At 500 °C, the wear scar surface demonstrates increased toughness, resisting plastic deformation due to high-temperature softening. Additionally, partial crystallisation occurs, leading to an overall increase in the hardness of coating. Combined, these factors reduce the wear rate of the coating.

Self-lubricating behavior of a PdCuNiP glassy alloy by in-situ nanocrystallization during dry friction

In the present work, dry-sliding behavior of a PdCuNiP bulk glassy alloy (BGA) was studied and compared with that of a ZrAlNiCu BGA. The PdCuNiP BGA exhibits a 2-fold smaller coefficient of friction (COF) and a 100-fold lower wear rate than those of the ZrAlNiCu BGA, although the PdCuNiP BGA shows the smaller hardness and fracture toughness. The unprecedented low COF and wear rate of the PdCuNiP BGA stem from in-situ formation of an amorphous/ultrafine nanocrystalline structure layer on the wear-scar surface during the dry sliding. The Von-Mises stress simulation mapping in the contact area reveals that the effect of stress and deformation is not the primary cause for the nanocrystallization. The model calculated frictional heat generated during the friction process causes the in-situ nanocrystallization, which increases the hardness and strength of surface layer. The self-lubrication effect results from the effective suppression of the sliding-induced plastic deformation and surface roughening.

Investigation of 1-octanethiol capped ZnS nanoparticles as lubricant additives and tribological behavior of oil-based nanolubricant

1-Octanethiol (OT) capped ZnS nanoparticles (OT-ZnS) as lubricating oil additives were investigated by tribological tests including wear tests and rheological measurements. The wear tests were performed on lubrication states using a custom design wear test device consisting of a rotating pin on a cylinder geometry. A rotating 1.2379 cylinder (steel counterpart) and a stationary C40 pin were used as a pair of test material for the wear test. The stationary pin was pressed against a rotating cylinder under lubrication conditions. It was observed that the synthesized OT-ZnS NP effectively improved the lubrication performance of 10W engine oil and the surface properties of the test materials. The addition of OT-ZnS NPs to the 10W base oil increased its viscosity and decreased the contact angle (CA) values. The results showed that the wear loss and the wear scar dimensions were both the lowest, while 0.0125 (wt.%) of OT-ZnS NPs were treated with the base oil. The mass loss of the pins was reduced to more than 6.3%. The wear reduction was observed at about 27% and the length of wear scar in the minor axis was reduced to 11.4% when a load of 100 kg was applied. The images of wear scars showed that the OT-ZnS NPs additives could prevent severe contact with the interacting surfaces. OT-ZnS NPs partially filled on the grooves and adhered on the wear scar surfaces and promote tribofilm formation, thereby it improve the tribological performance of 10W base oil, especially under extreme pressure conditions. Sulfide film (sulfuration layer) adhered to the wear scar surfaces and decrease the wear.

Study on the sliding wear map of cylinder liner − piston ring based on various operating parameters

The wear map can directly reflect the wear state and mechanism of the friction pair under different conditions and is widely used in wear prediction and fault diagnosis of steel materials. However, there are few reports on the wear map of the engine cylinder liner and its materials. In this study, the operating parameters were obtained through an engine bench test. The parameters near the cylinder liner's top dead center （TDC） were selected as wear test parameters. Thousands of hours of reciprocating lubrication wear tests were carried out on a multi-function wear tester. By analyzing the wear rate variation under different test parameters, the cylinder liner's wear state was divided into mild, medium, and severe wear. The morphology of the wear scar surface and cross-section of the cylinder liner was analyzed by scanning electron microscope (SEM) and then drawing the wear mechanism map. The results show that the primary wear mechanism under slight wear is spalling wear, accompanied by the plastic deformation phenomenon. Delamination wear is the primary mechanism in the medium wear state, accompanied by a small amount of massive spalling wear. The delamination wear is mainly caused by the crack generated by graphite in or below the deformation layer. The primary wear mechanism of the severe wear state is massive spalling. At this time, the graphite at the bottom of the deformation layer plays the role of primary cracks, which causes the plastic deformation layer to fall off.

Anti-corrosive non-aqueous DBSA/MEA lamellar liquid crystal lubrication system

HypothesisSince lamellar liquid crystals (LLCS) could be used for lubrication, many LLCS systems have been constructed to improve lubrication performance. However, most studies focused on the LLCS of the water system, and its corrosiveness brought some limitations to its application. Therefore, it is necessary to construct a non-aqueous LLCS system with good lubrication and anti-corrosion properties to improve its applicability. ExperimentsAnionic surfactant dodecyl benzene sulfonic acid (DBSA) was used to construct non-aqueous LLCS in different solvents, including monoethanolamine (MEA) and diethanolamine (DEA). DBSA/H2O LLCS system was constructed for comparison. The LLCS was characterized by polarizing microscope (POM), small-angle X-ray scattering (SAXS), and rheology. Its microstructure was discussed. Meanwhile, we evaluated the lubrication and anti-corrosion performance of LLCS. Its lubrication mechanism was explained through tribology tests and X-ray photoelectron spectrometer (XPS) analysis of the wear scar surface. Its anti-corrosion mechanism was investigated by using the weightlessness method, electrochemical test method, and quantum chemical theoretical calculations. FindingsThe DBSA/MEA non-aqueous LLCS system showed better lubrication performance than DBSA/DEA and DBSA/H2O LLCS. It can adsorb on the surface of the friction pair to form a lubrication friction film, which plays a better role in reducing friction and wear. The DBSA/MEA LLCS is less corrosive to metals because it can effectively isolate oxygen and water in the air between friction pairs. Furthermore, the lone pair electrons in the 2p orbital of the N atom in the MEA molecule could coordinate with the 3d empty orbital of the Fe atom, forming a protective film on the metal surface, which plays a good anti-corrosion effect. This work not only enriched the study of non-aqueous LLCS but also expanded its potential applications in the field of lubrication.

Elaboration of Ionic Liquids on the Anti-Wear Performance of the Reinforced Steel-Steel Contact Surface

This study conducted a tribological investigation of base oil (PAO6 and 5W 40) and ionic liquids (IL)-modified lubricants through a four-ball tribometer for 30 min. The lubricants were fabricated via a two-step method using stirring magnetic and ultrasonic dispersion. IL, base oil, and lubricants were, respectively, characterized by XRD and FTIR analysis. In addition, multiple characterizations such as EDS, 3D morphology, and SEM were carried out to evaluate the wear and friction performance of steel balls. Ultimately, the results showed that the coefficient of friction (COF) and wear scar diameter (WSD) of wear scar lubricated by IL-modified lubricants were greatly decreased than that by base oil. IL can well improve the tribological properties of PAO 6 oil and 5W-40 oil due to the tribo-film appearance on the friction surface of wear scar by the effective role of IL. Fascinatingly, this investigation comprehensively and elaborately put a new sight into the lubrication mechanism of how IL reacted with a base oil and enhanced the tribological characteristics.

Conductivity and tribological properties of IL-PANI/WS2 composite material in lithium complex grease

An ionic liquid-polyaniline/tungsten disulfide (IL-PANI/WS2) composite was synthesized in 1-butyl-3-methylimidazole tetrafluoroborate (LB104) aqueous solution by in-situ polymerization and characterized by Fourier transform infrared spectroscopy. A current-carrying friction and wear tester was used to study the tribological properties of steel—steel and copper—copper friction pairs lubricated by an IL-PANI/WS2 lithium complex grease (LCG). After the experiment, scanning electron microscope was used to observe the surface morphology of the wear scar on the steel and copper plates, and X-ray photoelectron spectrometer was used to analyze the elemental composition of the wear scar surface. The results show that compared with greases containing IL-PANI and WS2, greases containing IL-PANI/WS2 exhibit better antiwear performance when lubricating steel—steel friction pairs and better tribological performance and electrical conductivity when lubricating copper—copper friction pairs. Therefore, it can be concluded that WS2 and IL-PANI have a synergistic effect.

Influence of medical-grade montmorillonite on the tribological and safety performance of composite aluminum-based grease

Purpose This study aims to reduce the harm of industrial lubricants to consumers. Composite aluminum-based grease (CAG) was prepared, and medical-grade montmorillonite (M-MMT) was used to improve the antiwear performance of the prepared grease. Design/methodology/approach The influence of the additive (M-MMT) on the tribological performance is mainly investigated using a ball-disc wear tester, and the wear scar surface about the disc was characterized by white light interferometer and electrochemical workstation. Moreover, the cell viability test was used to evaluate the safety of the grease. Findings The results indicated that for the grease containing 1.5% M-MMT, the average coefficient of friction was reduced by about 46% compared with the CAG, the wear volume of the disc reduced by about 74%. Moreover, CAG and 1.5% M-MMT-containing CAG were proved safety by means of the cell viability test. Originality/value The integral properties of CAG can be improved with the medical-grade materials as the additives, while ensuring the safety.

Effect of plastic pyrolytic oil and waste cooking biodiesel on tribological properties of palm biodiesel–diesel fuel blends

PurposeThe purpose of this paper was to investigate the lubricity of palm biodiesel (PB)–diesel fuel with plastic pyrolysis oil (PPO) and waste cooking biodiesel (WCB).Design/methodology/approachThree quaternary fuels were prepared by mechanical stirring. B10 (10% PB in diesel) fuel was blended with 5%, 10% and 15% of both PPO and WCB. The results were compared to B30 (30% PB in diesel) and B10. The lubricity of fuel samples was determined using high-frequency reciprocating rig in accordance with ASTM D6079. The tribological behavior of all fuels was assessed by using scanning electron microscopy on worn steel plates to determine wear scar diameter (WSD) and surface morphology. The reported WSD is the average of the major and minor axis of the wear scar.FindingsThe addition of PPO and WCB to B10 had improved its lubricity while lowering wear and friction coefficients. Among the quaternary fuels, B40 showed the greatest reduction in coefficient of friction and WSD, with 7.63% and 44.5%, respectively, when compared to B10. When compared to B30a, the quaternary fuel mixes (B40, B30b and B20) exhibited significant reduction in WSD by 49.66%, 42.84% and 40.24%, respectively. Among the quaternary fuels, B40 exhibited the best overall lubricating performance, which was supported by surface morphology analysis. The evaluation of B40 indicated a reduced adhesive wear and tribo-oxidation, as well as a smoother metal surface, as compared to B20 and B30b.Originality/valueIncorporation of PPO and WCB in PB–diesel blend as a quaternary fuel blend in diesel engines has not been reported. Only a few researchers looked into the impact of PPO and WCB on the lubricity of the fuel.

Remarkably boosting the lubricity of polyalphaolefin by loading amphiphilic carbon dots stabilized by Span-80

The amphiphilic carbon dots (A-CDs) derived from Tween-80 were used as the lubricant additives of polyalphaolefin (PAO4) with the aid of Span-80. The Span-80 (5.0 wt%) endowed A-CDs with super dispersibility in PAO4 by the hydrogen bond interactions between the hydrophilic head groups of Span-80 and the oxygen-containing groups on A-CDs. At the load of 50 N, the biggest friction and wear reductions for PAO4 triggered by the A-CDs (1.3 wt%) stabilized by Span-80 (5.0 wt%) were 45.4 and 69.8%, respectively. The distinguished tribological performance of A-CDs stabilized by Span-80 illustrated the co-lubrication effect of Span-80 and A-CDs. The wear scar surface analysis results revealed that the A-CDs stabilized by Span-80 distinctly alleviated the adhesive and abrasive wear of friction pair. The favorable smoothness and high O content on wear scar surface lubricated by A-CDs suspension reflected the A-CDs stabilized by Span-80 have participated in the formation of effective lubricating films. The reasonable lubrication mechanism of A-CDs stabilized by Span-80 was discussed based on the co-lubrication effect of Span-80 and A-CDs. The absorbing effect of Span-80 and the rolling and filling effects of A-CDs are all beneficial to the building of lubricating films, thereby tremendously boosting the lubricity of PAO4. The A-CDs stabilized by Span-80 are promising to become a kind of eco-friendly and high-performance lubricant additive for PAO.

Tribological Property of ta-CNx:Ta Deposited via Ion Beam Assisted-Filtered Arc Deposition

Improving the hardness of amorphous carbon nitride with tantalum was realized by using ion beam assisted filtered arc deposition to obtain a low friction coefficient and low specific wear rate in ambient air. The coatings were prepared with different nitrogen flow during coating at different discharge cycles of tantalum. The wear scar and as-deposited surfaces were observed and analyzed by means of FESEM, AES, XPS, and Raman analysis. The lowest friction coefficient (~0.07) was obtained for ta-C:Ta200, which exhibited a low specific wear rate of < 1.0 × 10−7 mm3/Nm. The XPS analysis revealed the existence of amorphous Ta2O5, and the friction coefficient seemed to be positively correlated with oxygen desorption from the coatings.

Tribological properties of MoS2 and CaF2 particles as grease additives on the performance of block-on-ring surface contact

Recently, the performance effects of lubricant additives on greases have been actively investigated. In order to improve their properties of anti-friction, load-carrying capacity, wear resistance, corrosion resistance, and temperature-enhancing, some additives are added to greases. Determining the appropriate additive ratios is one of the most important research topics in tribology. In this study, friction, wear, and contact temperature were analyzed by adding MoS2 and CaF2 additives to the lithium soap grease. The experiments were carried out at different revolutions (200, 500 and 800 rpm), additive ratios (0.25, 0.5, 1, 1.5 and 2 wt%) and contact loads (72, 108 and 144 N) using a block-on ring tester. The structure and morphology of additives analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of additives on surface morphology and roughness were also characterized with the scanning electron microscopy (SEM) and profilometer. In addition, energy dispersive spectrometry (EDS) was used to detect the elements present on the wear scar surfaces. Results reveal that the MoS2 and CaF2 additives can improve the wear resistance of lithium grease and reduce the friction coefficient. In this experimental study, suitable additive ratios that are anti-wear and friction-reducer were found to be in the range of 1–1.5 wt% for both additives. Besides, both additives continued their friction-reducing characters at over the room temperatures. While the MoS2 additive oil gives the lowest friction and wear values, the same ratio of CaF2 additive oil shows a more stable operation.

Study on the Tribological Properties of F-T DS/ZnFe-LDH Composite Lubricating Material

The homemade soot capture device was used to burn Fischer-Tropsch synthetic diesel (F-T diesel) in order to simulate the combustion of F-T diesel in the engine and collect its soot (F-T DS, FS). The zinc-iron hydrotalcite (ZnFe-LDH) and the composite materials of FS and ZnFe-LDH (F-T DS/ZnFe-LDH, FS/ZnFe-LDH) were prepared by hydrothermal synthesis, and the similarities and differences in tribological characteristics of the above three lubricating materials such as 10# white oil (10# WO) lubricant additives were investigated. FS is an aggregation composed of amorphous carbon and graphite microcrystals. ZnFe-LDH is mainly composed of nanosheets, Zn, and Fe hydroxide particles, with a high degree of crystallization, while FS/ZnFe-LDH is a “sandwich layer” composed of nanosheets and soot particles. Because of the addition of cetyltrimethylammonium bromide and the grafting of a long carbon chain lipophilic group in the preparation process, FS/ZnFe-LDH has better anti-wear properties than the FS and ZnFe-LDH Effect. When FS/ZnFe-LDH is added at 0.2 wt.%, the average friction coefficient (AFC) and average wears scar diameter (AWSD) are at their lowest. Compared with pure 10# WO, the minimum values of AFC and AWSD have dropped by 36.84% and 22.58%, respectively. XPS analysis of the wear scar surface shows that when ZnFe-LDH and FS/ZnFe-LDH are used as lubricating additives of 10# WO, together with the organic matter in the white oil and the iron element in the friction pair, tribochemistry occurs under the combined action of the adsorption force and the tribochemical reaction, a friction protection film containing four elements of C, O, Fe, and Zn is formed on the surface of the wear scar, which effectively reduces the wear and reduces the friction coefficient.

高温高圧水含有エタノール中におけるDLC膜の摩耗メカニズム

DLC coatings have been applied to many automotive parts. This is because they have excellent properties such as low friction, high hardness, high wear resistance and chemical stability. Recently, bioethanol fuel has been attracting attention as a carbon-neutral fuel. However, the wear characteristics of DLC coatings under high-temperature and high-pressure environments, such as automobile engine environments, have not yet been clarified. In this study, friction and wear tests were conducted on Si-containing DLC coatings in ethanol containing high-temperature, high-pressure water. After friction test, we performed elemental analysis by Auger electron spectroscopy and AFM nano-scratch testing of wear scar of DLC coatings. As a result, it was found that the Si content suppressed the wear of DLC as the ethanol concentration increased, that the wear increased due to the effect of water, and that the wear increased due to the removal of the soft layer formed on the wear scar surface.

3D texture parameters for wear scars after severe regime

PurposeThis paper aims to present an analysis of several 3 D texture parameters for the entire wear scars obtained in severe regime, on a four-ball tester. The aim of this analysis is to correlate the tribological parameter as wear scar diameter to texture parameters.Design/methodology/approachTested lubricants were rapeseed oil, rapeseed oil additivated with 1% Wt nano TiO2 and rapeseed oil additivated with 1%Wt nano ZnO. The severe regime was applied for 1400 rpm and for loads increasing in steps of 50 N, from 500 to 900 N. Several analyzed roughness parameters (height parameters and functional ones) could be related to the evolution of a wear parameter, the wear scar diameter. Comparing the values for neat rapeseed oil and additivated variants, the texture parameters allow for evaluating if the additives protect or not the worn surfaces.FindingsMeasurements pointed out two groups of roughness parameters: one that has an evolution depending on wear scar diameter (WSD) and load (Sa, St, functional parameters) and one including Ssk that has shown no dependence on load and WSD. Also, the functional parameters Spk and Svk follow in a similar manner the wear parameter, WSD, but Sk is the least dependent on load. For the highest load, amplitude parameters such as Sa and St are following the tendency of WSD. Each lubricant has its particular correlation between wear parameters and texture quality, expressed by the help of a set of roughness parameters.Research limitations/implicationsSuch studies help tribologists to rank lubricants based on a combined analysis with wear parameters and texture parameters.Practical implicationsThe results allow for evaluating new formulated lubricants.Originality/valueThe study on the quality on worn surfaces introduces the original idea of analyzing the entire wear scar surface (approximated by an ellipse with the axes as those experimentally measured) by the help of a set of 3 D roughness parameters.

Impact of soot nanoparticle size and quantity on four-ball steel wear characteristics using EDS, XRD and electron microscopy image analysis

The effect of soot contamination on the tribological performance of engine oil was investigated. Carbon black is introduced to simplify diesel engine soot contamination. Besides, the tribological performance issue is verified by a four-ball tribometer. The steel ball worn surfaces were studied by Scanning Electron Microscopy (SEM), Optical Microscope (OM) and Energy Dispersive X-ray spectroscopy (EDX). In addition, Transmission Electron Microscopy (TEM) was used to investigate the morphology and nanostructure of soot and carbon black. According to the four ball test results, the average wear scar diameter of steel ball tested with engine oil blended with N220, N330, N550 and N660 by 1% by weight is larger than that of pure engine oil by 26%, 38%, 41%, and 39%, respectively. The wear scar diameter tends to increase after blended larger size of carbon black particle. The steel balls tested with formulated engine oil without soot contamination and with soot contamination by 0.5 wt%, 1 wt%, and 2 wt% have average wear scar diameters of 621, 567, 784 and 894 nm, respectively. On the other hand, wear scar roughness of steel balls tested with formulated engine oil without soot contamination and with soot contamination by 0.5 wt%, 1 wt%, and 2 wt% were 2.28, 0.25, 1.49 and 1.76 μm, respectively.Consequently, quantity of the soot nanoparticle approximately 0.5% by mass in engine oil significantly plays an important role in steel ball wear scar diameter and surface roughness reduction. Moreover, the agglomerated soot which is larger than the oil film thickness might block the lubricant from entering the contact. It leads to the breakdown of the oil film thickness resulting in increasing adhesive wear on the worn surface.

Tertiary Amine-Terminated Carbon Dots with Reversible CO2 Switchable Amphiphilicity as the Versatile Lubricant Additives

Tertiary amine-terminated carbon dots (CDs-TA) with reversible CO2 switchable amphiphilicity were synthesized as the versatile lubricant additives. First, the same batch of CDs-TA was used as the additives of various base lubricants including polyalphaolefin (PAO4), polyethylene glycol (PEG200), and H2O by the facile CO2 regulation. At the optimum adding concentrations, CDs-TA made the friction coefficients and wear volumes of the above lubricants reduce by 28.1–40.4 and 62.1–70.4%, respectively, exhibiting the excellent friction reduction and wear resistance functions. The wear scar surface analysis results revealed that CDs-TA as additives of PEG200 triggered the formation of a boundary lubrication film, which was in fact a heavy tribofilm with a thickness of more than 680 nm. Second, the recovery of CDs-TA from the discarded PAO4 was conveniently achieved by alternately bubbling of CO2 and N2 with the relatively favorable recovery rate. More importantly, the tribological performance of recovered CDs-TA was stable during six cycles of the recovery process, establishing the foundation for the recycle of CDs-TA as additives of PAO. This work is hopeful to open the door for broadening the application range and reducing the cost of CD-based additives in the lubrication field.

Design of low-friction and anti-corrosion a-C:H:SiOx films

Some properties of hydrogenated amorphous carbon (a-C:H) film are effectively improved via silicon (Si) and oxygen (O) incorporation, such as high friction coefficient (0.1–0.4) in the atmospheric environment and serious pitting corrosion caused by pores in the film. In this study, the Si and O incorporated a-C:H (a-C:H:SiOx) films were deposited by plasma-assisted chemical vapor deposition (PACVD) technology using acetylene (C2H2) and hexamethyldisiloxane (HMDSO) as precursors, and then studied their tribological and anti-corrosion properties in the atmospheric environment. The a-C:H:SiOx films exhibited impressive friction coefficient (0.05–0.07) and wear rate (1.8–5.6 × 10−7 mm3/Nm) owing to silicon oxide formed on surface of wear scar during friction process. Compared to pure a-C:H film, Si and O incorporated greatly increased the deposition rate of films. Therefore, a slightly increased wear rates of a-C:H:SiOx films are acceptable as long as the films are thick. In addition, the incorporation of Si and O makes the film have high resistance, thereby improving the corrosion resistance of the film. This excellent pitting corrosion resistance of the film can make up for the defects of the a-C:H film such as pinholes. The a-C:H:SiOx film with excellent tribological properties and corrosion resistance will have a good application prospect under the combined action of corrosion and mechanics.

Tribological performance of low viscosity halogen-free ammonium based protic ionic liquids with carboxylate anions as neat lubricants

The tribological performance of six low viscosity, hydrophobic, halogen- sulfur-, and phosphorous free trioctylammonium-based protic ionic liquids with 2-naphthoate, 4-tert-butylbenzoate, 2-hexyldecanoate, 4-phenylbutanoate, 3,4-dimethylbenzoate, and salicylate anions were studied as lubricants for steel-steel interfaces using a four-ball tribo-tester. The results showed a significant friction reduction up-to 28 ̶ 65% compared to polyalphaolefin lube base oil. Where the salicylate protic ionic liquid showed the lowest coefficient of friction. In terms of wear, the 2-naphthoate and salicylate protic ionic liquids exhibited wear scar diameter values lower than polyalphaolefin by 4.7% and 0.42%, respectively. The scanning electron microscopy and X-ray photoelectron spectrometer analysis outcomes of the wear scar surfaces indicated that tribo-chemical reactions were involved among the protic ionic liquid molecules and the steel surfaces during the tribo-test, developing a protective boundary film, which contributed significantly to the lubrication performance of the protic ionic liquids’ lubricants. No corrosion was observed for the copper strip corrosion test carried out to examine the corrosion characteristics of the studied protic ionic liquids. The overall results confirm the high capability of applying this group of protic ionic liquids as lubricants.