Antiwear Characteristics Research Articles

Solvation CoMFA-QSTR and CoMSIA-QSTR Models for Predicting the Antiwear Properties of Lubricant Additives

Abstract The relationship between the molecular structures of lubricant additives and their antiwear properties was assessed using 36 nitrogen-containing heterocyclic organic compounds to generate quantitative structure tribo-ability relationship (QSTR) models. In the modeling process, the molecular structure of the base oil was employed as the solvation factor, employing n-octadecane as a substitute for the liquid paraffin used to generate the original experimental data. Comparative molecular field analysis (CoMFA)-QSTR and comparative molecular similarity indices analysis (CoMSIA)-QSTR models incorporating solvation by n-octadecane were established and compared with QSTR models that did not involve solvation. The solvation CoMFA-QSTR and CoMSIA-QSTR models exhibited excellent fitting abilities and were highly robust when predicting lubricant performance. These models were superior to nonsolvation models in this regard. These models also generated useful information regarding potential changes to molecular structure to improve antiwear properties. Electrostatic fields were found to be very important factors in antiwear models. Because the original experiments used a nonpolar base oil, the solvation factor had no obvious effect on the antiwear characteristics of the polar additives and so the predictive abilities of the solvation and nonsolvation models were similar.

Tribological performances of α-Zrp as the additive of the grease used for mine hoisting wire rope

Considering that the lubrication failure of the wire rope in mine hoisting is easy to occur under harsh conditions, which will accelerate the wear of the wire rope and seriously threaten the safety of hoisting. Therefore, the anti-wear characteristics of α-type zirconium hydrogen phosphate (α-ZrP) on the wire rope grease used for mine hoisting were studied. First, the modified greases with different mass fractions of α-ZrP were prepared, and then the dispersion of α-ZrP in the original grease was discussed. Finally, the friction and wear properties of the α-ZrP modified greases were investigated by the four-ball machine, fretting wear test rig of steel wire and sliding wear test rig of wire rope. The results show that the coefficient of friction (CoF) increases first and then decreases with the increase of α-ZrP added in the grease in the four-ball friction test and the sliding wear test of wire rope. In addition, it will agglomerate in the original grease when the addition of α-ZrP is too large, which will worsen the lubrication effect, and the wear mechanism also changes from abrasive wear to abrasive wear and adhesive wear. Moreover, dry friction may occur between steel wires when the additive content is low, thus accelerating their wear. The improvement effect of the original grease is the most significant for the mine hoisting wire rope when the mass fraction of α-ZrP is 2.5% according to the principal component analysis theory.

Effect of Bionic Nonsmooth Surface Vane on the Antiwear Characteristics of Double-Vane Pump.

In order to improve the antiwear characteristics of the double-vane self-priming pump, the surface structure of the Scapharca subcrenata was extracted and reconstructed according to bionic principles. Three types of nonsmooth surface models were established at the outlet end of the suction surface of the vanes, which is the most severely worn in the double-vane pump. The external characteristics, pressure field distribution, wear area distribution, and wear degree of the volute and vanes at different concentrations of nonsmooth vane structure were investigated by numerical simulation to reveal the mechanism of the nonsmooth surface structure of the wear characteristics of the vanes. The results show that the head and efficiency of pumps with four different vanes decrease and the average wear rate increases as the particle concentration increases. The different vane structures have a very small effect on the wear resistance of the volute, but a larger effect on vane wear. The circular nonsmooth surface structure, which reduces the low pressure area of the inlet section of the impeller while ensuring a smaller drop in head and efficiency, produces the best antiwear effect and improves the antiwear performance of the double-vane pump.

Improving the antiwear characteristics of lubricants to improve the reliability of fire fighting equipment

An increase the level of its combat readiness, reliability and durability of fi re tighting can be ensured, among other things, through the use of high-performance lubricants in friction units of fi re trucks. The use of a metal-cladding additive for lubricants to improve their antiwear properties. The procedure for conducting tribotechnical tests is described. The results of tribotechnical tests of oil modifi ed by the developed additive are presented. The results obtained indicate a positive effect of the metal-cladding additive on the antiwear properties of the test oil.

Friction and anti-corrosion characteristics of arc sprayed Al+Zn coatings on steel structures prepared in atmospheric environment

Al coatings and Al–Zn coatings were prepared on the surface of Q345B steel after shot peening using supersonic arc spraying technology to improve anti-slip and anti-corrosion properties. The SEM, XRD and EDAX were used to detect the surface morphology, coating structure and phase composition of the two coatings. The anti-slip coefficient and anti-wear performance of the two coatings were detected by the anti-slip coefficient detector and the MRTR friction and wear tester, respectively. The anti-corrosion characteristics of the two coatings were obtained by the electrochemical corrosion workstation. The experimental results showed that the thickness of both coatings is 100 μm. The substrate and the coating are mechanically bonded. Under the condition of the test parameters, the anti-slip coefficients of Al coating and Al–Zn coating were 0.717 and 0.823, respectively, satisfying the service requirement of the steel structure. The corrosion potential of the Al–Zn coating was −1.136, which exhibits a good anti-corrosion performance. Under the condition of water, the anti-wear characteristics of Al–Zn were relatively ideal. The wear-resistance of Al–Zn coating is better than that of pure Al coating. In conclusion, Al–Zn coating possesses excellent anti-slip, anti-corrosion and anti-wear characteristics and can be used in large steel structure surface modification.

Application of Coatings with Smart Functions

To obtain the different types of technical utilities, the surface of various systems needs to be modified by altering surface properties using polymer coating(s) which is one of the emerging technologies to impart smart functions. The polymer coating has a wide application in various fields such as biomedicals, pharmaceuticals, packaging, corrosion control, electronics, and abrasion control. The coating can be done using both biodegradable and non-degradable polymers having eminent properties such as better mechanical strength, anti-wear characteristics, corrosion protection, electrical conductivity, biocompatibility, and high surface functionality. Several methods have been reported for the fabrication of defensive coatings. A thoughtful selection of polymers, coating methods, and critical process parameters may bring forth a better protective coating with advanced properties. This review discusses the objectives of the polymer coating, various coating technologies, and their smart applications.

Tribological Behavior of Ionic Liquid with Nanoparticles.

This research aims to formulate a new lubricant containing oxide nanoparticles for enhancing anti-wear ability and reducing friction. Different concentrations of copper oxide (CuO) and zinc oxide (ZnO) nanoparticles were separately added to an ionic liquid, methyltrioctylammonium bis(trifluoromethylsulfonyl)imide [N1888] [NTf2], to formulate the tested lubricants. The tribological properties of the lubricants were tested by performing ball-on-disc wear tests on a tribotester (MTM, PCS Instruments). The results show that both the CuO and ZnO nanoparticles can increase the friction reduction ability of the ionic liquid when used as a neat lubricant. The anti-wear characteristic of the ionic liquid is increased by adding ZnO nanoparticles but decreased by adding CuO nanoparticles. The best tribological performance observed for the concentration of 0.2 wt% ZnO, with the wear scar diameter is reduced by 32% compared to the pure ionic liquid. The results of SEM/EDX analysis on the worm morphologies show different lubrication mechanisms of the nanoparticles in the [N1888] [NTf2], which are tribo-sintering for CuO nanoparticles, and third body with pure rolling effect for ZnO nanoparticles.

Exploring the lubrication mechanism of CeO2 nanoparticles dispersed in engine oil by bis(2-ethylhexyl) phosphate as a novel antiwear additive

Energy-efficient engine oils are required for sustainable transportation using vehicles, and oil companies aim to manufacture lube oils with more effective additives. Here we investigate the lubrication mechanism of cerium oxide (CeO2) nanoparticles dispersed in a fully synthetic engine oil (5 W-30) by bis(2-ethylhexyl) phosphate (HDEHP). Tribological tests were conducted using a tribometer based on ASTMG181 to mimic the ring–liner tribosystem environment. The results showed that the CeO2 nanolubricant enhanced the antifriction and antiwear characteristics of the rubbing surfaces by 12–21% and 62–80%, respectively, contrary to the results obtained with the 5 W-30 oil. In-depth field emission scanning electron microscope, energy dispersive spectrometer, and X-ray photoelectron spectrometry analyses of the worn surfaces after lubrication evidenced the production of a tribofilm, induced by physical adsorption and tribochemical reactions. Concisely, this study demonstrates the superior tribological performance of the CeO2 nanolubricant and provides insights for developing lube oils and improving the fuel economy in vehicle engines.

Stearic Acid Reinforced Triboelectric Nanogenerator with High Output Performance and Anti-wear Characteristics for Self-powered Anticorrosion System

Low output performance and poor anti-wear characteristics are still obstacles for further development of triboelectric nanogenerators (TENG). Here, a novel approach to reinforce the output performa...

Preparation and tribological research of the electrodeposited Ni[sbnd]W alloy coatings for piston ring application

This study determines the effect of the electrodeposition process parameters on the composition, mechanical properties and wear resistance of NiW alloy coatings. The optimum conditions for the electrodeposition of a NiW alloy coating on a piston ring to increase resistance to wear and friction are determined. The results show that the content of tungsten (W) in the NiW alloy coatings is between 23.8 wt% and 42.2 wt%, depending on the DC current density and the concentration of the sodium tungstate in the electrolyte. The best mechanical properties are obtained for Ni-40.6 wt% W alloy that is annealed at 600 °C for 1 h. The tribological properties of the coating are determined using a pin-on-disk abrader tester under SAE 10W40 lubricated conditions. The tribological study shows that Ni-40.6 wt%W coating that is annealed at 600 °C for 1 h features a lower coefficient of friction and better anti-wear characteristics than a hard chromium coating that is currently widely used as a coating for piston rings. The resistance of a Ni-40.6 wt%W alloy coating for piston rings to wear and scratching is studied using a 125 cc, single-cylinder, air-cooled engine. The results show that the Ni-40.6 wt%W coating has good resistance to wear and scratching.

Rheological and tribological characterization of novel modified graphene/oil-based nanofluids using force microscopy.

In this study, it is aimed to improve the lubrication and anti-wear characteristics of nanofluids produced by the distribution of silane-modified graphene nanosheets into the base oil without any surfactant or dispersant. Nanofluids are among the hottest research topics currently studied in the literature due to their interesting thermal and rheological properties. Graphene nanosheet with unique physicochemical properties is a good alternative as a nanofluid component and a lubricant. In this study, the behavior of nanofluidic films on the material was investigated by using scanning probe techniques, phase-contrast microscopy, and friction force microscopy techniques. Due to stick-slip behavior and rheological properties that are dominant in the studied ranges, problems were encountered in performing tribological analyzes with friction force microscopy. On the other hand, these results have been beneficial in determining tribological factors in nanoscale. The presented nanofluids showed non-Newtonian behavior at high concentrations and shear rates and shown an improved tribological performance up to 43% in friction coefficient, 91% in wear, and 46% in thermal conductivity compared to the base oil.

Madhuca Indica (Mahua): A novel feedstock for bio based lubricant application treated with trimethylolpropane and tribological analysis

ABSTRACT The degradation of the lubricant is not possible as they are non-biodegradable and are toxic to nature. Around the globe, various studies are going on while concentrating on bio-based lubricant which could be environment friendly. In this analysis, friction and wear of the Mahua oil-based lubricant have been carried out at different loads. The mahua oil was treated with trimethylolpropane for improving lubrication characteristics and then blended with synthetic oil in the ratio 4%, 8%, and 12% by volume. The proper mixing of the blends was done with help of ultrasonicator. The loads assigned were 20, 80, and 140 N. The tribological analysis at various loads was assessed using a pin on disc tribometer. The sliding velocity of the disc on every load applied has been 0.4 m/s. The lubricating framework that existed during the experiment constituted boundary lubrication. Improvement in frictional behaviour and anti-wear characteristics was shown by 4% and 8% blends of Mahua oil at all the applied loads. The 12% blend shows maximum friction and wear. The worn surface images were better obtained with 4% and 8% blends.

Tribological performance of engine oil with graphene oxide nano additives on cylinder liner honing surface at high contact pressure

Improving the friction and wear characteristics of lubricants employing dispersed nanoparticles is a major area of research. This paper focuses on the wear and friction analysis of a plateau honed cylinder liner surface when lubricated with Graphene oxide nanoparticles dispersed in SAE 15 W40 API CH4 diesel engine oil. Experiments are carried out on a reciprocating tribometer. The friction coefficient and wear rate are used to quantify the tribological characteristics of lubricant added with nano-particles. On contrary to the past observations on polished surfaces, experiments conducted using honed engine liner and engine oils with nanoparticles have shown improvement only on the wear characteristics. It is noted that in case of a honed engine liner surface under high contact pressure lubricated with oil dispersed with 0.5 mg/l of Graphene oxide, the anti-wear characteristics improve by 37% whereas the coefficient of friction has only marginal improvement.

Effect of heat treatment on the microstructure, microhardness, and wear characteristics of AlCrFeCuNi high-entropy alloy

The comprehensive properties exhibited by dual-phase high-entropy alloys (HEA) increase their prospects of finding use in engineering applications. However, the distribution of the phases that are present in the alloys has a significant effect on their mechanical performance. Therefore, the homogeneity of microstructure in these alloys remains critical for the improvement of their mechanical properties. In this study, AlCrFeCuNi HEA was fabricated by a direct laser metal deposition technique. The effect of heat treatment on the microstructure, microhardness, and wear performance of the alloy was investigated. The microstructural analysis revealed that the alloy was characterized by a dendritic microstructure with a dual-phase (BCC + FCC) composition. Microstructural changes were achieved at all heat treatment temperatures with grain growth starting to occur at 950 °C and dissolution of the BCC phase happening at 1100 °C. Good anti-wear characteristics were obtained for alloy heat treated at 950 °C.

Early failure for wear after ceramic-on-highly cross-linked polyethylene total hip arthroplasty: a case report

BackgroundHighly cross-linked polyethylene (HXLPE) enhances the anti-wear characteristics of the conventional polyethylene (PE). Early failure for wear after ceramic-on-highly cross-linked polyethylene (CoHXLPE) total hip arthroplasty (THA) is extremely rare.Case presentationWe described the case of a 60-year-old man who underwent right CoHXLPE THA because of the developmental dysplasia hip (DDH) complained pain 32 months after this procedure. Plain radiographs showed that eccentric wear existed at the polyethylene insert. However, the patient refused surgery at that time and did not stop weight-bearing. The right hip pain continued for 7 months. Plain radiographs of the pelvis showed that the HXLPE liner was penetrated and partial inner wall of acetabular shell was worn. Acetabular cup revision was performed, and the ceramic head and HXLPE were exchanged.ConclusionsDifficult reduction during primary THA, especially for DDH, can result in higher abductor tension, which may lead to early eccentric wear of the prosthesis. Whenever eccentric wear of HXLPE liner was found, weight-bearing must be stopped to avoid the accelerated wear and adverse reactions to metal debris (ARMD).

Nanoscale viscosity of triboreactive interfaces

It has been long speculated that the good antiwear properties of the nano-thin triboreactive interfaces might have a rheological origin that can greatly influence their friction, lubrication and antiwear characteristics, which account for nearly one quarter of the worldwide total energy consumption. However, the measurement of the nanoscale viscosity of such tribological interfaces is still a challenging task. This is mainly due to their ultralow thickness, i.e. typically < 150 nm, high viscosity and reactivity, which make the currently used bulk, interfacial or micro-gap rheological techniques inadequate. Here we demonstrate two methods, i.e. creep and squeeze flow, that can be used to quantify the viscosity of triboreactive films in-situ as they form and ex-situ after formation. Films generated from the zinc and ashless dialkyldithiophosphate (ZDDP and DDP) antiwear additives were analysed as model systems because of their industrial and academic importance. The results confirm that the formed tribofilms behave as molten glass with an average viscosity ranging from 2 × 1 0 11 to 7 × 1 0 12 Pa s. During its formation, the molten glass showed rich intrinsic rheological properties that allowed them to maintain local order on the nanoscale through the motion and reconfiguration of single and multiple patches within the formed film, which can significantly predetermine its superior antiwear properties. The findings of this study open future opportunities for optimizing the nano-flowable glass to efficiently control the lubrication of tomorrow’s engines without the need of any environmentally harmful oil additives. • Triboreactive films behave as molten glass with rich intrinsic rheological properties. • Local order at the nanoscale predetermines the friction and wear performance. • Nano-flowable glasses are the key to efficient lubrication in tomorrow’s engines. • Single asperity AFM is fully capable of probing the flowability of surfaces nano-patches for energy harvesting and other applications.

A novel approach in developing environment-friendly bio-lubricant from coconut oil, mustard oil and its methyl esters

The environmental issues caused by synthetic lubricant oils necessitate the need for an environment-friendly lubricant. In this study, a novel approach is proposed for developing an environment-friendly bio-lubricant by blending mustard oil, coconut oil and its methyl esters. Properties of the bio-lubricant are studied and compared with commercial ISO VG 32 oil. The best among various blends prepared are selected based on a decision matrix. The results revealed that this method helps in pour point depression and also in achieving excellent oxidative stability as compared to the base vegetable oil. The newly formulated oil has a pour point lower than that of commercial oil and is found to be highly biodegradable. The anti-wear characteristics of the oil are improved using boric acid, and the viscosity of the oil is improved using ethyl vinyl acetate for meeting the industrial standards. The newly formulated oil complies with industrial standards and can be used as biodegradable lubricant oil.

Multifunctional Tunable Polymethacrylates for Enhanced Shear Stability and Wear Prevention

This paper describes the design, synthesis, and characterization of linear, polar, and nonpolar polymethacrylates designed for use as lubricant viscosity index (VI) improvers with enhanced shear and antiwear resistance. The polymers were prepared via reversible addition–fragmentation chain transfer to obtain relatively low and narrow molecular weights, with random polar moieties. The resulting polymers were evaluated as oil solutions to determine their VI, shear stability performance, and antiwear characteristics. The polymers had molecular weights (Mw) ranging from 120 to 170 kDa, and the resulting VIs, in general, tracked the Mw. Although the VIs were modest (140–189), all polymers displayed higher values than a commercial product designed for similar applications, both at 2% (w/w) and when kinematic viscosities (KVs) were normalized to the lowest KV100 of ∼6 cSt. One of the imidazole-containing polymers displayed an anomalously high VI for a low apparent Mw. As hypothesized, many of the polar polymers demonstrated substantial wear reduction compared to the nonpolar homopolymers or a commercial benchmark. The low-molecular weight imidazole-containing polymer produced less than 4% of the wear displayed by the commercial standard. The higher molecular weight polymers containing imidazole, hydroxy group, and amino group also produced as little as 10% of the wear shown by the benchmark. The strategy demonstrated the benefit of low and narrow molecular weight polymers to achieve good shear stability in viscosity modifiers while minimizing wear, rendering them suitable for fluid power applications.

Investigation on wear behaviour of SS 316L, atmospheric plasma and high velocity oxy-fuel sprayed WC-Cr3C2-Ni coatings for fracturing tools

The application of WC based coatings could minimise the failure of fracturing tools during downhole drilling and hydraulic fracturing. The oil and gas industries are experiencing maintenance challenges due to excessive wear caused by fracturing fluid containing a high concentration of proppants. The tribo-behaviour of atmospheric plasma spray (APS) and high-velocity oxy-fuel (HVOF) deposited WC-Cr3C2-Ni coatings on SS 316L substrate were investigated. The uncoated and coated specimens comparatively studied in dry sliding and oil-based fracturing fluid conditions. The characterisation of coatings for surface morphology, porosity, and nano-hardness was carried out. The ball-on-disc tribometer (ASTM G99) used for tribo-tests with Al2O3 balls as a counter body against uncoated and coated specimens. The experimental analysis suggested that both coatings revealed higher hardness and improved anti-wear characteristics compared with uncoated specimens. Moreover, for detailed information about wear mechanisms, the worn-out surfaces of uncoated and coated specimens were studied. Consequently, the outcomes show the potential use of WC-Cr3C2-Ni coatings to enhance the performance and lifespan of fracturing tools operating in hostile conditions, which is essential in economic savings during maintenance and replacement of components.

Performance of Additives Concerning Synergistic Effect in Lube Oil

Lubricating oils containing ester, gaining more importance due to their friction reducing ability. Screening the performance of lubricating oils prior to field test is of most significance for the new lubricant formulations. In this endeavor, six lubricating blends were formulated having variable concentration of additives (sulfur and ester) in mineral oil and screened for their performance using four-ball tribo-tester. The formulated blends were evaluated for their extreme pressure and anti-wear characteristics as per ASTM standards. Tests were conducted on DUCOM TR- 30L four-ball tester and wear scar diameter were measured on an optical microscope.Compatibility and synergy of additives have been discussed on the basis of various parameters such as anti-wear scar diameter, mean scar diameter (just below weld load), mean scar diameter (at last non-seizure load), weld load and load wear index. The findings of this study demonstrate that ester along-with sulfur not only boost anti-wear properties but also enhance load carrying capacity of oil. An addition of sulfur beyond 2 % may not yield any significant improvement of tribo-characteristics of these oils.This paper is highlighting the synergistic effect of additives to render it as suitable lubricant for metal working applications. This paper also suggested an optimum concentration of an additive for its suitability for anti-wear and/(or) extreme-pressure properties.