The failure of moving mechanical components is often accompanied by hydrogen embrittlement caused by hydrogen diffusion in steel. One considerable mechanism for hydrogen diffusion is its ingress from lubricant decomposition. We investigated quantitatively the ingress of hydrogen generated by lubricant decomposition into bearing steels using time-of-flight secondary ion mass spectrometry (ToF-SIMS)

A grooved texture surface was fabricated to enhance the wear resistance of the guide rail surface of molding machine. The effects of sand concentration in the oil and the groove width on the tribological properties were studied using a pin-on-disk tribometer. Surfaces with groove widths of 1000 μm (S1) and 1500 μm (S2) had lower friction coefficient and better anti-wear properties than a non-grooved

The CoCrMo alloys are commonly used in artificial joints. However, tribocorrosion phenomena have led to the search for improvements to diminish wear debris and ion release. The engineering of surfaces has been an alternative to achieve this purpose. In the present study it was investigated the tribological effect of AlCrN, AlTiN, AlTiON and AlCrON coatings deposited on cast CoCr alloy. The coatings

This work presents a study on tribological behavior of surfaces obtained by turning in sintered self-lubricating composites. Turned surfaces were obtained at constant cutting speed (vc = 100 m/min), feed (f = 0.2 mm), and depth of cut (ap = 1 mm). The tested composites have solid lubricants (graphite and hexagonal Boron Nitride - hBN) mixed in a Fe-C-Ni-Si matrix manufactured by single (SP) and double

The elastohydrodynamic (EHD) lubrication straight contact line conjunction is studied to evaluate the mixed lubrication heat generation experimentally over bordering operational conditions in a disc-on-disc machine. An experimental investigation is carried out using an accessory device that collects and measures the outlet lubricant temperature. The experimental results show the typical transition

This article proposes a new thermohydrodynamic (THD) bearing design method based on an improved version of a precedent method. The precedent method used two charts prepared in advance to easily and quickly find two crucial predicted data of the maximum bearing temperature and the effective temperature of the bearing oil film to be used later in an isoviscous Reynolds equation. Three sets of charts

The different fretting wear behaviors of alloy 690TT in air and in a flowing nitrogen environment were revealed. Moreover, the grain refinement to nanoscale caused by fretting wear in nitrogen was investigated. The results showed that when compared with the air environment, the coefficient of friction in nitrogen was slightly higher due to direct contact between the metals with strong adhesion which

In this work, a systematic investigation was carried out to study the electrochemical and tribocorrosion behavior of LY12 aluminum alloy sliding against Al2O3 pin in artificial seawater, using a pin-on-disk tribometer combined with an in-situ electrochemical workstation. The results revealed that the cathodic shift of open circuit potential and two order of magnitude increase in current density caused

This paper makes the first attempt to present the experimental investigation on fretting wear behavior of piezoceramics P51, PSnN5 and PLiS51 against Si3N4 ceramic ball under air condition. The sphere-on-flat contact pattern is used as the contact model. The influences of the displacement amplitude, frequency and normal force are taken into account. After each test, friction logs are used to determine

The effect of the annealing treatment on wear performance of hot-rolled wear-resistant steel/carbon steel cladded plate was investigated. The novel cladding that can provide high wear resistance, strong structure and low cost is typically employed for the metallurgical mining equipment, agricultural machinery, coal mining and other industries, which could provide equipment with high wear resistance

AISI D2 steels are an interesting family of tool steels that generally found applications in knife blades, shaper blades as well as forging and punching dies owing to its optimum toughness, lower wear rate and relatively high hardness. The present research work aims at designing a new heat treatment cycle consisting of single tempering followed by cryogenic treatment and soft tempering with the intention

The texture of die surface plays an important role in the tribology of metal forming processes. The surface texture is defined by surface roughness and its orientation, which is influenced by the manufacturing processes. In this research, the effects of various die machining operations on the frictional condition in the forming process of CK45 steel are investigated by means of ring compression test

Carbon fibre reinforced polymers (CFRP) are often exposed to solid particle erosion wear due to small particles moving freely in the atmosphere or in the environment and their impact on aircraft bodies. In this study, fibre weaves of CFRP composite materials of the following types were produced; uni-directional (U), plain weave multidirectional (P) and twill 2 × 2 weave multidirectional (T). Tests

The frictional vibration, generated at water-lubricated rubber bearings operating under low-speed, heavy-load, start-up and shutdown conditions, can severely degrade the reliability and the sheltered performance of underwater vehicles. The rubber layer of the ship stern tube water-lubricated rubber bearings is easily elastically deformed under certain loads, which affect the damping performance of

Ni-Ti-C metal matrix composites (MMC) with in situ formed, homogeneously distributed titanium carbide (TiC), as well as graphite (C) reinforcement in nickel metal matrix, were synthesized using Mechanical Alloying (MA) followed by Spark Plasma Sintering (SPS). The main objective of this research is to consolidate Ni-Ti-C MMCs with varying the C/Ti ratio and characterize the MMCs to investigate the

During their lifetime, gears may undergo starved lubrication operating conditions. Starvation condition has an impact on friction between gears that leads to modify gearbox efficiency. In this paper, lubricant starvation tests on an FZG test rig adapted to this condition are presented. Gears were equipped with embedded thermocouple sensor to measure their operating bulk temperature. An experimental

Ethylene–vinyl acetate (EVA) foam is sometimes used in the outer soles of sport shoes. To improve the slip resistance of EVA foam, this study investigated the effects of porosity and the fraction of styrene–ethylene–butadiene–styrene (SEBS) on the dry sliding friction behavior of EVA foams. Sliding friction tests were performed against a pin specimen with a semicylindrical tip, which was covered with

The purpose of this study was to design a tribo-tester that can evaluate the lubrication performance of ferrofluids under the effect of the magnetic field. A novel bronze-based tribopair was fabricated with the potential to employ a controllable magnetic field in such a way that it accurately mimics the friction of thrust pad bearing. The designed experimental scheme enables direct measurement of the

During acceleration and deceleration processes of a bearing, the kinetic relationship of collision and friction between the cage and the rolling element is complex, which has an important influence on the dynamic characteristics and stability of the rolling bearing. In this study, experimental investigation of dynamic motions of a cage under various external radial loads was performed during acceleration

The tribological and vibrational behaviours of conventional and textured spur gear pairs have been experimentally explored under fully flooded and starved lubricating conditions at different operating parameters. Three different textures on gears’ teeth profiles were created by placing the dimples of vertically oriented ellipsoid, horizontally oriented ellipsoid and hemisphere in the zigzag patterns

To increase the efficiency of a gearbox, research on gear mesh loss is of importance. Britton at al. concluded that the surface finishing method affects the gear mesh efficiency. The efficiency benefits of super finishing a surface and reducing the surface roughness have been reported by Kahraman. A novel method for calculating the bearing loss-torque was proposed by Tu et al. Andersson found that

Effects of thermo physical properties of crambe, linseed, and jojoba oils, a typical petroleum-based lubricant (PBL), and blends of crambe oil and PBL on their tribological performance were investigated. Biolubricants showed better lubricity (i,e., lower coefficient of friction). At 55 N load, linseed and jojoba oils had the lowest and PBL had the highest wear. At 90 N and 160 N normal loads crambe

A recent interest on emergency shoe braking in high speed trains stimulated the research on the damage due to sliding contact between brake blocks and wheel tread. Bi-disc tests, with rolling/sliding contact between specimens extracted from wheels and brake blocks, were previously performed in constant working conditions to reproduce the temperature of the wheel during stop braking. However, stop braking

The commonly used quasi-static model for angular contact bearings is enhanced by coupling the contact mechanics and bearing kinematic analyses with traction or friction behavior in ball-to-race contacts. The points of pure rolling in the contacts, which constitute the primary inputs in the kinematic equations, are determined by minimizing the frictional dissipations based on a prescribed elastohydrodynamic

One of the urgent problems that have yet to be addressed in the field of drilling engineering is how to further improve the working performance of rock bit journal bearings (RBJBs) and prolong its service life under complicated conditions of low speed, heavy load, and high temperature. Generally, reasonable surface texture parameters serve as an effective means for enhancing the lubrication and anti-wear

An innovative VCN coating with C element doped in VN matrix was developed on Inconel 718 and Si (100) substrates using a multi-arc ion plating technique. The micro morphology and microstructure of the as-deposited VCN coating were studied by scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscope (XPS). The results show that the incorporation

Magnetron sputtered PVD thin-film TiB2 coatings were investigated to be a wear-resistant cam tappet coating which runs under the boundary lubrication regime in internal combustion engines (ICEs). A high negative biased AISI 52100 samples were coated at RF powers of 150, 170 and 190 W. Coatings were characterized via nanoindentation, SEM/EDX, XRD and Raman analysis. Friction and wear behaviors of these

Electroplated bolts have been widely used in the automotive industry for many decades. In the present work, for the first time, the role of each layer of the bolt coating (i.e., electroplating, passivate and topcoat layer) on the coefficient of friction of a bolted joint were experimentally and systematically investigated. The coefficient of total friction (μtot), coefficient of friction between threads

Copper and graphite are main compositions of copper-based brake materials commonly used in the field of high-speed train. Their interaction influenced the tribological performance of copper-based brake materials. In this paper, with copper and graphite as compositions, three kinds of layered samples were prepared as pins, which were tested against the disc made of H13 steel. Friction tests were conducted

Due to the unique redox characteristic of CeO2, addition of CeO2 in diesel fuel reduces diesel engine emissions; however, its influence on the friction and wear performance of the fuel injection system is not clear. In this work, CeO2 were synthesized and modified. CeO2-diesel fuel blends with different concentrates prepared. The dispersion stability of the CeO2 and modified CeO2 in diesel fuel blends

ABSTRACT A simple and inexpensive corrosion sensor has been manufactured to study the corrosion rate of new and water contaminated lubricating grease using a galvanic cell. The galvanic charge is developed between ENIG (electroless nickel immersion gold) and zinc, manufactured by selectively plating on a custom manufactured interdigitated PCB (printed circuit board). This paper shows the methodology

An abnormal phenomenal of rail corrugation was found in the transition and circular curve interval of the mountain city metro, in which the rail corrugation on the outer rail is more serious and earlier than that on the inner rail, and the wavelengths are also different. In the present paper, the frictional self-excited oscillation of the wheel-rail system and the feedback vibration of the rail corrugation

To reduce the irregular typewriter noise in main bearings of engine, a comprehensive experimental study about the effect of carbon black particles (CBPs) with different particle sizes, concentrations and standing times on noise in the oscillatory parallel plate squeeze oil film test apparatus has been carried out. The results show that the presence of CBPs can significantly reduce the generation of

This paper presents a numerical analysis of elastohydrodynamic lubrication (EHL) with grease in point contacts to predict the grease film thickness at low speeds, which can increase with decreasing the speed and exceed the base oil film thickness by orders of magnitude. The grease film thickness is obtained by solving the EHL problem, taking grease flow as a single-phase flow with a non-Newtonian viscosity

There is a grinding fine grain layer of high-speed train wheel after machining treatment. In this paper, the influence of grinding fine grain layer on rolling contact fatigue (RCF) property is studied by GPM-30 fatigue tester. The results show that there is a 1μm thickness fine grain layer after grinding treatment. The grinding fine grain layer can improve the RCF life of wheel samples. The formation

The relatively high toughness, high adhesion to steel, and low internal stress of hydrogenated amorphous carbon (a-C:H) films containing Ag make them good candidate materials for various applications in sensors, tribology, and biomaterials; however, the relatively low hardness and poor tribological properties in oxidizing environments hinder their broad use. Incorporating a small amount of Si in Ag/a-C:H

In gear transmission systems, the reliability of lubrication is essential to its life. An approach to predict the reliability of gear elastohydrodynamic lubrication (EHL) under a random input torque is proposed in this paper. Firstly, a single-freedom nonlinear stochastic dynamic model that considers backlash, a time-varying mesh stiffness, and random loads is established to obtain the probability

A complete thermohydrodynamic lubrication model for pump-out spiral groove thrust bearings (SGTB) with cavitating flow is established based on two-phase flow and transport theory. Various effects (cavitating flow interface effect, convective heat transfer effect, heat conduction effect, inertia effect, breakage and coalescence of bubbles) of water lubricant at high speed are included when modeling

The present work aims to investigate the sliding friction and wear behavior and related emissions of airborne particulate matter of Cu-free barite containing friction materials for vehicular brake pads. In particular, the effect of different concentrations of phenolic resin used as a binder has been considered. Tribological tests were conducted using a pin-on-disc laboratory tester. During running-in

The braking performance of copper-based brake pads containing Cu-coated SiO2 and uncoated SiO2 was tested on a reduced-scale dynamometer. Results showed that both the stability of the friction coefficient and the wear resistance are improved and the fade phenomenon of the friction coefficient is effectively alleviated during continuous emergency braking (350 km/h, 0.48 MPa) by introducing Cu-coated

Wet clutches are widely used in vehicle transmission systems to start and shift. The temperature field of the wet clutch components is influenced by friction and is closely related to the vehicle performance and service life. This work improves the numerical modelling of the temperature field by taking into account the groove cooling, the local heat dissipation and the time-varying friction coefficient

Water-miscible metalworking fluids (MWFs) are used in metal removal and forming operations. For end-use, formulation concentrates are diluted in water - providing conditions conducive to microbial growth and metabolism, and potentially causing fluid biodeterioration and microbiologically influenced corrosion. Microorganisms in the environment are highly diverse and bacteria and fungi had been recovered

The tribological performance of ceramic–polymer composites prepared by high-pressure (3 GPa) compression molding of silicon nitride (Si3N4) and polytetrafluoroethylene (PTFE) with epoxy resin (EP) binder was investigated under dry friction conditions. Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy, and energy-dispersive spectroscopy (EDS) were utilized to

The tribological behaviors of silicon nitride sliding upon sintered polycrystalline diamond (PCD) were explored via altering pH levels. High reductions in the friction and wear are achieved when sodium hydroxide solution is introduced at the contact interfaces. This reduction is found to depend on the pH value of the alkaline solution. The friction coefficient and wear loss of silicon nitride vary

This work presents an approach for modeling grease-lubricated bearing wear by coupling models for boundary-lubricated wear and bearing lubrication state. The lubrication model takes a mass balance approach, using previously developed models for pressure-driven side flow loss and centrifugally driven bleed supply mechanisms. These are combined with a contact model to determine the level of surface interaction

For over a decade, hard coatings have been providing wear resistance to cutting tools materials. The industrial prerequisites and advancements in hard coatings provide drastic improvements with respect to productivity and component lifetimes and hence reduce cost. However, selection of a desirable coating is often not straight forward, in view of the fact that the number of hard coating materials and

In complex operational environments, random shocks change the contact behavior of rough surfaces, resulting in time-dependent and uncertain characteristics, which further affect their friction, wear, and lubrication properties. However, in the currently available impact models, only deterministic shocks are considered at surfaces in contact and the evolution of contact behavior over time is ignored

Chain continuously variable transmissions (CVTs) are attracting attention as the next-generation practical application, which utilize lubricated rolling/sliding contacts for transmitting the engine power. However, their flexible structure sometimes causes vibration and noise problems which need to be solved. In this study, friction tests were conducted for a rolling/sliding contact lubricated by test

Hybrid pump-controlled asymmetric cylinder drive systems are implemented for energy-saving purposes in applications that do not require fast responses. Under low-velocity and low-pressure conditions, the friction influence in the hybrid pump-controlled system is evident. Researchers have developed various models to describe friction. These friction models are implemented based on the relative motion

High-performance coatings with self-lubrication, superior wear and corrosion resistance are sought-after in modern industry. Here we reported a Cobalt-Nickel/Tungsten disulfide (Co-Ni/WS2) composite coating fabricated by a pulse electrodeposition approach. The codeposition of WS2 significantly affects the microstructure, hardness, tribological and electrochemical behaviors of the Co-Ni/WS2 composite

This article aims to investigate tribological properties of a surface modified by laser texturing under full oil lubrication as well as the effect of laser texturing on the abrasion resistance properties. Laser texturing was carried out to fabricate a spherical bulge texture on the surface of GCr15 bearing steel using an SPI fiber laser. Rriction and wear tests were performed to simulate the actual

The premature failure of cutting tools during machining of titanium alloys is primarily attributed to their low thermal conductivity and strain hardening. The coefficient of friction (CoF) at the tool-chip contact depends on the high stress-strain values, interface temperatures, and the velocity of the chip. In this work, a new tribometer is developed to overcome the drawbacks of the existing tribometer

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

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

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

(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 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

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

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

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