FeS-Cu copper-based self-lubricating bearing materials are prepared by mechanical alloying and powder metallurgy. The effects of ball milling time on the microstructure and properties of the material are analyzed. The dry friction properties of the material are tested on a pin–disc contact reciprocating test machine with the load of 200·N. The morphology and composition of the wear surface are observed

Both the mechanical properties and friction characterization of graphene–silicone rubber composites were investigated systemically. Graphene–silicone rubber composites were prepared by means of solution and flocculation process to improve the processing performance and avoid agglomeration. It was found that the tensile strength, elongation at break, and tear strength of graphene–silicone rubber composites

In some industrial devices, the use of a sliding contact to transmit power currents or communications signals is required. The physical and, in particular, tribological understanding of these electromechanical systems is therefore a major issue. Thus, this article reports a theoretical and numerical study accounting for the mechanical influences about the electric transport properties of a sliding

An experimental study is conducted for friction systems introducing damping components consisting of different materials and different configuration. A number of experiments are performed on a pad-on-disc experimental test rig. Dynamic and tribological analyses are performed to evaluate the effects of different damping components on the stick–slip behavior. The obtained results indicate that friction

This study investigates the performance of three ionic liquids (ILs), trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate, trihexyl(tetradecyl)phosphonium decanoate, and 1-butyl-3-methylimidazolium tetrafluoroborate, as lubricant additives in synthetic oil polyalphaolefin (PAO8) and bio-based oil trimethylolpropane trioleate (TMPTO). The ILs were added at 0.5, 1.0, and 1.5 wt% concentrations

A 3D finite element (FE) model was developed to investigate the effects of refurbishing on rolling contact fatigue (RCF) behavior of through-hardened bearing steel in a circular contact. In this investigation, the material degradation due to fatigue in original and refurbished domains was modeled using continuum damage mechanics (CDM). Material damage, crack initiation, and propagation in a circular

Carburizable martensitic stainless steels (MSSs) are attractive candidates for bearings due to their high corrosion resistance, high hardness, and high temperature performance. Wear performance in tribocorrosion applications is strongly influenced by the surrounding environment. Electrochemical testing was used to evaluate three different surface treatments on AMS 5930 steel developed for advanced

Abstract Earlier studies have shown that the load-dependent friction behavior of various gear oils can affect their pitting performance; that is, low friction resulted in a long pitting life. These studies were limited, however, to test methods and running conditions quite different from those occurring in actual gear transmissions. In the present study, a more gear-like twin-disc machine with test

In order to study the tribological properties of PTFE modified by hard nanoparticles and soft polymer under dry friction conditions, the tribological properties of polytetrafluoroethylene (PTFE) filled with different volume contents of polyether ether ketone (PEEK) and nano-ZrO2 were investigated at a linear speed of 2 m/s, normal load of 200 N, and ambient temperature conditions for 60 min using a

The performance of surface-active additives, such as friction modifiers, depends on their interactions with surfaces. Their effectiveness thus hinges upon the surface conditions. In this work, the effect of cleaning methods of test substrates on the friction reduction capabilities of different organic friction modifier (OFM) additives was investigated. 52100 steel discs and balls were the test specimens

Arbitrary velocity vectors on two meshing surfaces in spiral bevel gears could generate large sliding velocity, which may cause a tremendous temperature rise, especially when surface roughness is involved. However, available studies are primarily concentrated on full-film lubrication without considering temperature rise and surface topography. The purpose of present study is to develop a mixed thermal

High-chromium cast iron with high nitrogen content (HNHCCI) was prepared using a vacuum induction barotropic furnace, and the erosion–wear behaviors of HNHCCI were investigated with a rotary erosion–wear tester. Results show that most of the nitrogen in HNHCCI dissolves into the matrix and some nitrogen forms carbonitride in the solidification process. The relative wear resistance of HNHCCI can reach

This study is a continuation of our previous work. It aims to characterize the tribomechanical and tribochemical behaviors of Ti3SiC2 in low-viscosity liquids. We found an interesting phenomenon in which the flowing and nonflowing states of ethanol are related to the tribological behavior of Ti3SiC2. Low friction and wear were obtained in flowing ethanol, which is due to the lubrication of the products

(Ti,Mo)B2-(Ti,Mo)C-(Fe,Cr)7C3 particle-reinforced laser cladding coatings with different contents of Y2O3 were prepared on a hot forging die steel substrate. The microstructure and wear behaviors were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), block-on-ring room temperature wear testing, and ball-on-disc high-temperature wear testing. The results showed that rectangular-like

This work presents a tribological evaluation of the influence of graphite and bronze fillers in two commercial composites in a dry sliding pin-on-disc test at the same contact severity ( PVa parameter) and four testing conditions (varying both normal force and sliding velocity). Both fillers, in comparison to pure PTFE, significantly affected the coefficient of friction (COF) and the mass loss. The

Numerical models for barrel-shaped rings with four textures were established using MATLAB and the corresponding specimens were fabricated by laser surface texturing. The performance was compared both theoretically and experimentally in order to investigate the effects of geometrical characteristics. The results of the theoretical analysis indicated that a microdimple texture on both sides of the ring

The effects of ultra-high-molecular-weight polyethylene (UHMWPE) as a filler on the tribological and mechanical properties of two biocompatible epoxies were studied. SU-8 and Structalit 8801 (a trade name) were the two biocompatible epoxies selected for this investigation. UHMWPE powder (40–48 μm particle size) was added to the selected epoxies to tailor their mechanical and tribological properties

MAX phase composites Ti3SiC2–TiCx and Ti3SiC2–(TiCx + TiC) were synthesized and consolidated via a powder metallurgy spark plasma sintering (SPS) technique. The bulk compositions and microstructural evolution of the resulting SPS discs were analyzed using X-ray diffraction, Raman spectroscopy, and scanning electron microscopy (SEM) paired with an energy-dispersive spectroscopy (EDS) system. The tribological

Fiber brushes with expanded graphite (EG) as a lubricant were successfully prepared. Compression properties of brushes filled with unbent fibers and bent fibers with different packing fractions were compared. Moreover, the friction and wear behaviors of the brushes with the same fiber packing fractions (17.5 vol%) but different EG volume contents were investigated. The effect of EG content on the tribological

Fine particle peening (FPP) is a peening process using fine shots with an average diameter of less than 200 µm. Pairs of twin-disc specimens made of carburized and quenched 18CrNiMo7-6 gear steel were subjected to two different FPP processes and conventional shot peening (CSP) using big shots with an average diameter of 600 µm. Rolling–sliding tribology tests were carried out under oil lubrication

Abstract Recently, concentrated polymer brushes (CPBs) have attracted much attention as potential tribomaterials showing an ultralow friction coefficient (e.g., 10−4 in a microtribological analysis). In this study, a homemade apparatus modeling reciprocating seals was developed, which consisted of an inner steel rod and an outer steel ring with a narrow clearance less than several tens of micrometers

Machining error in machining processes arises due to several factors. The tilt angle of the spindle of the machine tool is one of the important factors that directly affect the shape error, surface quality, and roughness of the machined part. In order to better analyze the effect of microscale effects on the tilt angle of a hydrostatic spindle, a fluid control model at the microscale is introduced

The present work presents the experimental analyses of a rigid (short) and a flexible (long) rotor subject to thermal unbalance effects. The rotors are supported by a ball bearing and by a cylindrical journal bearing. The differential heating generated in the journal bearing is responsible for the thermal unbalance. The results obtained with the short rotor at 7 krpm showed an increase in the synchronous

Commercially prepared spherical zirconia (ZrO2) nanoparticles with an average particle diameter of 5 nm and functionalized with a hydrocarbon ligand were dispersed in a polyalphaolefin (PAO) base oil, producing a 10-nm stabilized zirconia nanofluid. The resulting nanofluid’s properties were characterized, including thermal conductivity and viscosity. A preliminary study of the nanofluid’s ability to

Abstract This article evaluates the frictional performance of different bearing grease formulations in full rolling bearings and a ball-on-disc rig and subsequently assesses whether the ball-on-disc test results can be used to predict the grease performance in actual bearings. A selection of custom-made greases with systematically varied formulations as well as their base oils were tested. Bearing

The present study investigates the effect on the tribological behavior of paraffin grease incorporated with ZnO and CuO nanoparticles. ZnO nanoparticles of ∼32 nm were synthesized with a precipitation method. X-ray diffraction (XRD), Fourier transform infrared (FTIR), high-resolution scanning electron microscopy (HR-SEM), and energy-dispersive spectroscopy (EDS) were used to characterize the nanoparticles

Drag torque is common in wet clutches, and the mechanism of drag torque at high circumferential velocities is not yet well understood. In this article, fluid action, rub-impact action, and rotary moments, as well as the coupling motion relationship between the friction plate and steel plate in 3 degrees of freedom, are taken into consideration to establish the fluid–solid coupling dynamic model of

The study of rotating machines stands out in the context of systems and structures due to the significant number of typical phenomena that may be present during the operation of such equipment. Rotating systems play an important role in industrial environments, with a wide range of application, namely, pumps, turbines, generators and compressors, and turbochargers, among others. Given this context

A nanocrystalline layer was fabricated on the surface of 42MnCr52 steel by ultrasonic surface rolling processing (USRP). Plasma sulfonitrocarburizing (PSNC) was performed on the untreated surface and nanostructure surface to obtain a composite layer composed of the solid lubrication layer (FeS) and nitrocarburized subsurface layer. The effect of the nanocrystalline layer on PSNC was investigated using

In this article, rare earth (RE)-modified carbon nanotubes (CNTs) were obtained by surface modification of multiwalled carbon nanotubes (MWCNTs) with rare earth LaCl3, and composite materials were prepared by using epoxy (EP) resin as the matrix. The modified CNTs were characterized by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy

In this study, a transient mixed lubrication model that considers mass-conserving cavitation and deterministic asperity contacts is established to study the evolution of the tribological behavior of spiral-groove thrust bearings during start-up. To overcome oil film thickness discontinuity at the edges and the complicated boundary shape of spiral grooves, a boundary-fitted coordinate system transformation

Seal failure is a common phenomenon that occurs when using a dry gas seal. Many seal failures occur during the start-up process of the seal. In this study, the state evolution of a dry gas seal during repeated start–stop operations was investigated using an acoustic emission (AE) method and a modified empirical mode decomposition using masking signals (MS-EMD). It was evident that the liftoff speed

Churning power losses are an important portion of transmission load-independent power losses, especially in high-speed condition and dip-lubricated gearboxes with high immersion depth. Generally, it is difficult to calculate the churning power losses due to the parameters of stirring oil and many other operating conditions. In this article, a method is proposed to determine the factors that influence

(2020). Correction. Tribology Transactions: Vol. 63, No. 1, pp. 194-195.

The film stiffness of dry gas seal must be sufficient to keep gas film stable at high and low speed. A generalized geometric model based on triangles is proposed to characterize spiral grooves. A mathematical model is established and solved using the finite-difference method to obtain steady performance. The optimum spiral grooves for maximum opening force and film stiffness are obtained at low speed

In the present work, three kinds of halogen-free ionic liquids (ILs) incorporating long-chain quaternary phosphonium as cations and dioctylsulfosuccinate (DOSS) as the anion were synthesized and characterized and the tribological properties of phosphonium ionic liquids were investigated as neat lubricants for steel ball–steel disc friction pairs at room temperature (RT) and elevated temperature (100 °C)

The friction and wear behavior of 1-octyl-3-methylimidazolium lactate ionic liquid (L-L108) between steel surfaces was investigated in ball-on-disc sliding friction tests. At an applied load of 5 N and rotating speed of 200 rpm, the friction coefficient of L-L108 was measured as 0.023, which is about one third and one fifth the values of ionic liquid L-P108 (0.068) and SAE 10W-40 engine oil (0.107)

As a 3D printing technology, selective laser melting has remarkable advantages such as high processing flexibility, high material utilization, and short production cycle. The applications of selective laser melting technology in industry have become quite extensive. There are many tribological studies on selective laser melting materials, but few based on water lubrication (Zhu, et al., Journal of

Two-body abrasive wear tests of Fe-B alloys with various matrix microstructures were performed using a pin-on-disc tribometer at a normal load of 3 N. The wear behavior was analyzed using scanning electron microscopy (SEM) and color 3D laser scanning microscopy. The results show that the Fe–2 wt% B alloy is mainly composed of a metallic matrix, M2B and M23(C, B)6. A pure pearlitic matrix occurs at

Solid-lubricated rolling bearings are widely known in many technical systems where conventional lubrication, such as oil or grease, fails due to critical conditions like vacuum or high temperatures. Polymeric cages (e.g., polyimide) endowed with molybdenum disulfide (MoS2) particles and silver (Ag) coating on the bearing components have proven themselves as dry lubricants that could significantly increase

A lubrication model of the piston ring–cylinder liner tribosystem taking account of the honing texture was established in this study. The impact of honing texture parameter, which was characterized by its crossing angle α, groove depth dp, and groove density de, was investigated experimentally and numerically to evaluate the lubrication performance of this tribosystem. The experiment was performed

Nickel and titanium are common elements in coatings. When Ni and Ti are combined they offer promising characteristics; specifically, the NiTi intermetallic phase. NiTi is a shape memory alloy possessing a stress-induced reversible martensitic transformation. NiTi alloys are used in a variety of industrial applications and are prevalent in the automotive, aerospace, and medical sectors. The problem

The stretching, shearing, deformation, peeling, and temperature rise phenomena at the micro–nano contact interface have a great influence on its tribological properties and significantly affect the service life of key moving parts made of polymers. The physical properties of the three typical polymer materials used for ship bearing polymer materials (ultra-high-molecular-weight polyethylene, synthetic

The effect of surface topography on lubricated systems plays a crucial role in terms of friction performance, because surface micro-irregularities can improve the load-carrying capacity of mechanical parts in lubricated conformal and nonconformal contacts. Sintered materials, which can be applied to manufacturing several mechanical components such as gears, axial thrust bearings, and disc brake pads

A tolerancing method highlighting trade-offs against key design variables of mechanical systems is proposed and applied to herringbone-grooved gas journal bearings. Gas bearings typically suffer from a subsynchronous instability, demanding a very tight tolerance on the bearing clearance and groove depth. Classical optimization techniques look for the most stable design, which does not necessarily lead

Polyamide (PA) is used in industrial applications such as automotive, gears, bearings, and pipeline spacers. As a bearing material, PA can support high contact pressures under low sliding speeds. To achieve high-performing and durable contacts, it is necessary to have low friction, low vibration, and low wear between PA and steel contacts at different operating temperatures. This study proposes the

Due to new pollutant emissions standards, internal combustion engines need several emission control strategies (and related procedures) such as exhaust gas recirculation, diesel/gasoline particulate filters, and selective catalyst reduction that allow them to comply with complete requirements defined on those standards. These strategies result in faster degradation of engine oil, one of the most relevant

Different Cu-based brake pads applied in high-speed railway trains were fabricated by the co-addition of Cr and CrFe particles, and the influence of the Cr/CrFe ratio on the tribological behavior of the powder metallurgy brake pads were studied by a reduced scale testing apparatus with the pad-on-disc configuration under various braking speeds. The results indicated that the Cu-based brake pad containing

Based on the structural features of a double-row tapered roller bearing (DTRB), a test rig for multipoint temperature measurement was built to investigate the temperature filed characteristics of DTRB under different operating conditions. Firstly, the composition of the test rig and the measuring instruments are described and the loading method is introduced. Secondly, a multipoint temperature measurement

In recent years, extensive use of smart lubricants has been made in order to control the tribological performance of fluid film bearings. The grooved surfaces of the journal bearing greatly influence the performance of bearings. In the present work, various geometric shapes of herringbone grooves (rectangular, triangular, and parabolic) with groove angles (30° and 60°) have been considered to numerically

In an effort to improve the surface properties of electrical contact materials in terms of high friction coefficient and wear rate, diamond-like carbon (DLC) films containing different metal elements were prepared on stainless steel substrates using an unbalanced magnetron sputtering system. In the present study, the effect of current-carrying on DLC film, Cu-doped DLC film (Cu/DLC), and Ti-doped DLC

Based on experimental life data on silicon nitride balls, the stress-life exponent and life constant in the generalized ball life equation, developed earlier, are modified to better simulate the fatigue life of silicon nitride balls in hybrid ball bearings. The modified ball life equation is then integrated with generalized life equations for the outer and inner races to model the life of a complete

In this study, a novel analytical model considering practical oil pressure and a cantilever plate bending calculation method is proposed to calculate the deformation of a vertical hydrostatic guideway. Based on the governing equations of rectangular thin plates, the finite integral transformation theory and the series-by-item differential transformation theory are used to solve the bending deformation

The influence of diamond-like carbon (DLC) coating positions—coated flat, coated cylinder, and self-mated coated surface tribopairs—on the fretting behaviors of Ti-6Al-4V were investigated using a fretting wear test rig with a cylinder-on-flat contact. The results indicated that, for tests without coating (Ti-6Al-4V–Ti-6Al-4V contact), the friction (Qmax/P) was high (0.8–1.2), wear volumes were large