Low Friction Research Articles

Study of structural and mechanical properties of composite ceramics of the AlMgB14–TiB2 system

AlMgB14 ceramics is known as a material characterized by increased hardness in combination with a low friction coefficient. Composite structures based on this ceramics have even higher strength characteristics. In the present work, we investigate the structural-phase states and physicomechanical properties of composite ceramics of the AlMgB14–TiB2 system with a variable TiB2 content, obtained by hot pressing the initial batch based on AlMgB14 and TiB2 ceramic powders preliminarily synthesized by the method of self-propagating high-temperature synthesis. It was found that the resulting materials are characterized by a composite structure represented by TiB2 inclusions distributed in the AlMgB14 matrix. The phase composition of the resulting composites is similar to the phase composition of the initial batch, with 5 to 9 wt. % of the MgAl2O4 spinel phase being formed. The microhardness of AlMgB14–TiB2 composites is up to 19.9 GPa (the hardness of AlMgB14 ceramics obtained by a similar method without additives is 7 GPa). The three-point bending strength of AlMgB14–TiB2 composite materials is 309 MPa.

Friction in Oil-Lubricated Rolling–Sliding Contacts with Technical and High-Performance Thermoplastics

Thermoplastics show great potential due to their lightweight design, low-noise operation, and cost-effective manufacturing. Oil lubrication allows for their usage in high-power-transmission applications, such as gears. The current design guidelines for thermoplastic gears lack reliable estimates for the coefficient of friction of oil-lubricated rolling–sliding contacts. This work characterizes the friction of elastohydrodynamic rolling–sliding contacts with technical and high-performance thermoplastics with oil lubrication. The influence of polyoxymethylene (POM), polyamide 46 (PA46), polyamide 12 (PA12), and polyetheretherketone (PEEK), as well as mineral oil (MIN), polyalphaolefin (PAO), and water-containing polyalkylene glycol (PAGW), was studied. Experiments were carried out on a ball-on-disk tribometer, considering different loads, speeds, temperatures, and surface roughness. The results show that, for fluid film lubrication, there is very low friction in the superlubricity regime, with a coefficient of friction lower than 0.01. Both sliding and rolling friction account for a significant portion of the total friction, depending on the contact configuration and operating conditions. In the mixed to boundary lubrication regime, the sliding friction depends on the thermoplastic and rises sharply, thus increasing the total friction.

Simulating Pelvis Kinematics from Belt and Seat Loading in Frontal Car Crash Scenarios: Important Boundary Conditions that Influence the Outcome.

The risk of submarining during automotive crashes, defined by the lap belt sliding off the pelvis to load the abdomen, is predicted to increase in future autonomous vehicles as greater variation in seating position is enabled. Biofidelic tools are required to efficiently design and evaluate new and/or improved safety systems. This study aims to evaluate the pelvis response sensitivity to variations in boundary conditions that directly influence the pelvis loads, deemed important for the submarining outcome, to facilitate a more precise comparison between finite element human body models (FE-HBMs) and post-mortem human subjects (PMHSs). A parameter study, using a one-variable-at-a-time analysis (low/high) of belt friction, seat friction, seat stiffness, and (on/off) for added belt bending stiffness, was performed using a state-of-the-art FE-HBM in four different test scenarios; one stationary, two sleds with upright occupant posture, and one sled with reclined occupant posture. In the stationary scenario, both belt friction and belt bending stiffness influenced the belt folding behavior, which consequently affected the belt-to-pelvis angle at submarining. In the sled scenarios, only seat friction was found to influence the pelvis kinematics and submarining outcome, with the most biofidelic response resulting from both the low (0.2) and high (0.5) friction coefficient depending on the scenario. To reduce uncertainty in boundary conditions affecting the external pelvis loads and increase confidence in FE-HBM to PMHS comparisons, it is recommended that future experiments evaluate the PMHS to seat friction coefficient and that new belt modeling methods that accurately capture belt folding when interacting with soft tissues are developed.

A novel spine tester TO GO.

Often after large animal experiments in spinal research, the question arises-histology or biomechanics? While biomechanics are essential for informed decisions on the functionality of the therapy being studied, scientists often choose histological analysis alone. For biomechanical testing, for example, flexibility, specimens must be shipped to institutions with special testing equipment, as spine testers are complex and immobile. The specimens must usually be shipped frozen, and, thus, biological and histological investigations are not possible anymore. To allow both biomechanical and biological investigations with the same specimen and, thus, to reduce the number of required animals, the aim of the study was to develop a spine tester that can be shipped worldwide to test on-site. The "Spine Tester TO GO" was designed consisting of a frame with three motors that initiate pure moments and rotate the specimen in three motion planes. A load cell and an optical motion tracking system controlled the applied loads and measured range of motion (ROM) and neutral zone (NZ). As a proof of concept, the new machine was validated and compared under real experimental conditions with an existing testing machine already validated employing fresh bovine tail discs CY34 (n = 10). The new spine tester measured reasonable ROM and NZ from hysteresis curves, and the ROM of the two testing machines formed a high coefficient of determination R 2 = 0.986. However, higher ROM results of the new testing machine might be explained by the lower friction of the air bearings, which allowed more translational motion. The spine tester TO GO now opens up new opportunities for on-site flexibility tests and contributes hereby to the 3R principle by limiting the number of experimental animals needed to obtain full characterization of spine units at the macroscopic, biomechanical, biochemical, and histological level.

Wear studies on friction stir processed surface modified AZ61 magnesium alloy with nano titanium oxide

ABSTRACT Surface modification of magnesium alloy enables the improvement of wear characteristics for use in sliding applications and places where surface hardness improvement is essential without affecting the microstructure of the underneath material. In this study, a pin-on disc wear test was used to examine the dry sliding wear behaviour of AZ61 Mg alloy reinforced with nTiO2 by a recursive friction stir processing technique. The trio-behavior of the surface-modified Mg alloy was detailed by the response surface methodology-central composite design matrix with the use of design experiments, considering three levels of reinforcement (%), sliding speed, and axial load parameters. In order to achieve the desired results of minimal wear loss, lower friction coefficient (COF), and lower friction force between surfaces (FF), this present work employed design expert software to develop a generative mathematical model to optimize the process parameters. Wear mechanisms were investigated using images captured by scanning electron microscope.

Wear Behavior of TiAlN/DLC Coating on Tools in Milling Copper–Beryllium Alloy AMPCOLOY® 83

In recent years, the exponential growth of the machining industry and its needs has driven the development of new manufacturing technologies, more advanced cutting tool types, and new types of coatings to extend tool lifespan. New coating solutions have been studied and implemented for machining tools, which provide a low friction coefficient and lubrication, thus increasing tool lifespan. Following this line of reasoning, it is relevant to develop scientific work aimed at studying the behavior of cutting tools coated with thin films that promote low friction and high lubrication, as is the case with DLC (diamond-like carbon) coatings. These coatings promote good resistance to oxidation and allow high machining speeds, properties also exhibited by TiAlN (titanium aluminum nitride) coatings. In fact, there is a gap in the literature studying the performance of cemented carbide tools provided with multilayered coatings in milling operations of Cu–Be alloys, commonly used in inserts of plastic injection molds. This study’s objective was to investigate the effect of a multilayer coating (TiAlN/DLC) on end-milling tools to analyze their cutting performance when milling a Cu–Be alloy known commercially as AMPCOLOY®83. The quality of the machined surface was evaluated, and the wear of the cutting tool was studied. A comparative analysis of milling parameters with respect to their effect on the condition of the surface after machining and the resulting wear on the tools, using coated and uncoated tools and different machining parameters, allowed us to verify a better quality of the machined surface and wear quantified in approximately half when used coated tools.

MPFEM investigation on densification and mechanical structures during ferrous powder compaction

Metal powder compaction is a crucial process in powder metallurgy, significantly affecting the final properties of compacts. However, the quantitative characteristics of multi-scale mechanical structures and the microscopic densification behavior, taking into account the influence of friction conditions, remain unclear. This study utilises a two-dimensional multi-particle finite element method to analyse the ferrous powder compaction. The evolution of powder densification, powder deformation and multi-scale mechanical behaviour under different friction coefficient conditions are analyzed quantitatively and qualitatively. Results reveal that powder densification occurs in distinct stages, with lower friction coefficients promoting greater powder densification, as observed from relative density and coordination number. Additionally, as the axial strain increases, plastic strain gradually rises whilst roundness decreases. Higher friction coefficients are associated with higher equivalent plastic strain but lower powder roundness. The Von Mises stress exhibits different stages of increase with the increment of axial strain. Powders with lower friction coefficients exhibit lower levels of Von Mises stress. As axial strain increases, the number, length, strength and direction coefficient of force chains undergo different evolution processes. Force chains exhibit longer length, fewer numbers, lower strength and lower direction coefficients at lower friction coefficients.

Tribological properties and related effects of compressed, thermally modified and wax-impregnated wood

AbstractThis paper develops a process for the preparation of modified wood with low friction and low wear for tribological applications such as self-lubricating bearings. Two types of wood, beech (Fagus sylvatica) and robinia (Robinia pseudoacacia), have been studied and the results compared with naturally lubricated native lignum vitae. The process developed consists of plasticisation followed by compression in a mould, thermal modification and subsequent wax impregnation. Plasticisation was carried out by conditioning the samples to a low equilibrium moisture content of 10%, followed by heating to a sample core temperature of 80 °C. This process protects the internal wood structure from mechanical damage during densification. After plasticisation, the wood was compressed in a press mould. A low springback effect (SBE), resulting in compression of up to 40%, was achieved by unloading the mould without opening it. This step optimises compressive strength and hardness. Subsequent heat treatment reduces thickness swelling by up to 85%. Finally, a wax impregnation was applied to reduce friction. Sliding wear tests on modified beech wood have shown that the lowest wear occurs in the cross-sectional orientation (load perpendicular to the fibre ends; rxt orientation). Sliding friction studies using a steel ball on a ball-on-disc tribometer showed that compressed and thermally modified samples impregnated with rapeseed wax or beeswax exhibited coefficients of friction in a range of 0.08 to 0.09. These values are almost four times lower than those of plain compressed wood and even lower than those of lignum vitae, which was used for plain bearings decades ago. This study clearly demonstrates the high potential of compressed, thermally modified and wax-impregnated wood.

Effect of electrical current on sliding friction and wear mechanisms in a-C and ta-C amorphous Carbon coatings

This study investigated the sliding wear behaviour of amorphous carbon (a-C) and tetrahedral amorphous carbon (ta-C) coatings, two forms of diamond-like carbon (DLC) coatings, against SAE 52100 steel using a modified ball-on-disk tribometer with applied electrical currents ranging from 100 mA to 1800 mA. It focused on the variations in sliding friction and wear characteristics of these coatings as electrical currents increased under constant load and speed conditions. The a-C coatings exhibited lower coefficient of friction (COF) values and reduced volumetric wear losses up to 1500 mA, while ta-C coatings studied displayed higher wear, similar to uncoated M2 steel, at 300 mA with degradation occurring at low currents, resulting in failure due to severe oxidational wear. The a-C coatings showed no significant electrical damage at these currents. Raman spectroscopy revealed structural changes on the wear tracks of sp2-rich a-C coatings, specifically the formation of graphene layers. In comparison, the wear tracks of sp3-rich ta-C coatings did not display such transformation under the conditions studied. The graphene coverage on the surfaces of the a-C coatings increased with the increase in the current as revealed by the Raman intensity maps of 2D peaks and this increase was accompanied by a higher defect density in the graphene. The low COF of graphene-covered a-C surfaces was consistent with the proposed mechanisms of moisture adsorption. However, at currents exceeding 900 mA, surface temperatures of a-C coatings exceeded 100 °C, impairing graphene's ability to maintain low friction, resulting in an increased COF.

Using lubricant composition to control friction-induced-vibration in an elastomer-steel contact representing a hydraulic seal

Hydraulic seals are key industrial components that can suffer from unwanted friction induced vibration (FIV). The types of FIV mechanism that occur in these components, and how they may be controlled, are not well known. We conducted sliding friction tests on contacts between seal materials, lubricated by hydraulic fluids, under speeds and contact pressures typical of hydraulic machines. FIV that occurred under certain conditions was captured and analysed. Results suggest 1) two FIV mechanisms are occurring: classic stick-slip and speed dependant friction instability, the 2) occurrence and severity of these mechanisms are correlated with the ratio of static to dynamic friction and the gradient of the friction vs. speed (Stribeck) curve, respectively, 3) these parameters can be controlled by including an appropriate additive package in the lubricant and this significantly reduces FIV, 4) most FIV occurs at low temperature and high load since these both lead to low kinetic friction (due to thicker hydrodynamic films and smoother surfaces) and thus promote stick-slip. This may explain instances of noise known in practice as the “Monday-morning effect” and suggests how this too may be alleviated through lubricant formulation.

Influence of silica and alumina nanoparticles on the wear and mechanical behavior of Indian almond fiber reinforced natural composites

Natural composites are valued for their lightweight, cost-effectiveness, and environmental benefits, but they often fall short in performance compared to conventional materials. To enhance their properties, nanoparticles are added. This study focused on natural composites made from Indian almond fiber, with alumina and silica nanoparticles incorporated. The scope of this research was to develop the Indian almond based materials as industry ready by enhancing its strength with nano-fillers. Four composites were created: C0 (Epoxy/Indian almond), C1 (Epoxy/Indian almond/Silica), C2 (Epoxy/Indian almond/Alumina), and C3 (Epoxy/Indian almond/Silica/Alumina), using a resin-to-fiber ratio of 70:30 and 3 wt% nanoparticles. The inclusion of nanoparticles improved composite performance, with C2 demonstrating superior mechanical and wear properties. Specifically, C2 achieved high tensile strength (84 MPa), flexural strength (122 MPa), impact strength (7.31 kJ/m2), and hardness (86 shore D), along with smallest wear and friction coefficient. HIGHLIGHTS Natural fiber based material was prepared by means of Indian almond fiber in addition to epoxy resin Silica and alumina nano-additives were added for further strengthening of composite Indian almond/Silica/Alumina composite’s functioning was investigated Indian almond/Alumina composite exhibited better tensile, flexural and impact strengths Indian almond/Alumina composite showed high hardness, slightest wear plus low friction coefficient

Current-carrying low friction of hydrogenated amorphous carbon film

Hydrogenated amorphous carbon (a-C:H) films, which equip excellent low friction performance but insulated, are naturally excluded from sliding electrical contact applications. In this work, we achieved current-carrying low friction of a-C:H film by utilizing a triboelectric triggered ignition effect. Protective resistors were introduced in the circuit during run-in for effectively alleviating undesired arc ablation. A T-shape crystalline structure of graphite was observed in the wear track by transmission electron microscopy. The parallel-aligned graphite at the top surface induced low friction, while the vertical-aligned graphite in the interior formed efficient electron transmission channels. This study expands the selection range of current-carrying friction films and provides a novel insight for the design and regulation of current-carrying friction films.

Difference in High-Temperature Tribological Performance of Oxide/Ag-MoS2-Based Composites

MoS2 has excellent vacuum lubricating performance. However, it is prone to be oxidized in a high-temperature atmospheric environment, leading to the deterioration of its lubricating performance and even serious space accidents. The high-temperature lubricating performance of MoS2-based solid lubricating materials can be improved to some extent by the co-compounding of appropriate oxides and Ag. The tribological properties of several common nano-oxides (ZnO, TiO2, Al2O3, and ZrO2) composited with metal Ag of MoS2-based composites were compared at 450 °C. The results showed that the comprehensive tribological performance of MoS2-TiO2-Ag was the best, an the average friction coefficient of about 0.26, and a wear rate of about 1.2 × 10−5 mm3/Nm, which was 18% and 43% lower than that of MoS2-Ag, respectively. The excellent tribological properties of MoS2-TiO2-Ag composites were attributed to three aspects: Firstly, with the help of the oxidation resistance of TiO2 to MoS2 to some extent and its high ionic potential, its oxidation resistance was improved and its shear strength was reduced to provide low friction. Secondly, relying on the low shear strength and good film-forming tendency of soft metal Ag on the sliding surface, a low shear tribo-film was easily formed on the friction interface, which was helpful for the synergistic lubrication of Ag, MoS2, and TiO2.Thirdly, through the matching of hard TiO2 and soft Ag, the wear resistance and bearing capacity of the composites were improved to some extent. The research results can provide some reference for the selection and design of MoS2-based high-temperature lubricating materials and the enhancement of their tribological properties.

Identification of non-circular profiles in hydrodynamic journal bearings

Hydrodynamic bearings, especially cylindrical radial plain journal bearings, are widely utilized in industry for their high load capacity and low friction energy losses. However, these bearings are prone to faults such as wear and ovalization, which can deform their circular profile and affect their vibrational response. Detecting these faults is essential to reduce their impact on production. This study introduces a methodology to identify hydrodynamic bearings with non-circular profiles. The bearing model and its numerical solution are implemented using the Finite Volume Method, with the effects of failures incorporated into a rotating system modeled by the Finite Element Method. A dataset is generated to reflect three common failure conditions in industrial applications: wear, ovalization, and a combination of ovalization with wear. The authors used this dataset to train a Multilayer Perceptron (MLP) neural network, which can identify the bearing profile shape based on specific attributes of the dynamic responses. The identification tests for the three fault conditions demonstrated high accuracy, particularly in distinguishing between ovalization and wear.

Design correlations for a novel enhanced compact heat exchanger with offset circular fins

A novel core geometry for compact heat exchangers, termed “circular offset fins (cOF)”, is proposed and experimentally investigated in the present work. This core design resembles the well-known offset strip fins used in efficient compact heat exchangers, with a key difference that instead of having rectangular fluid flow passages between deflections, this design features circular paths, resulting in fins with semicircular profiles. An experimental study examined heat transfer and pressure drop characteristics for five different core geometries. These geometries varied in passage diameters, lengths, and degrees of obstruction. The experiments were carried out over Reynolds numbers ranging from 500 to 3000 at different core wall temperatures. Data was analyzed using Kays and London's steady-state steam-to-air heat transfer technique to determine the empirical Colburn factor. The empirical Fanning friction factors for these geometries were also obtained. The asymptotic behavior of the Colburn and Fanning friction factor data allowed for the development of correlations in the function of Reynolds number and geometry dimensionless parameters. The proposed correlations predict data within ±6 % and ±8 %, respectively. The impact of different geometric parameters on core performance was assessed using the Colburn and Fanning friction factors, as well as area and volume goodness factors, and compared to rectangular offset strip fins. Direct comparisons showed that circular offset fins consistently exhibited a lower friction factor than rectangular fins. Although its Colburn factor was lower than rectangular fins up to a Reynolds number of 2000, circular fins it surpassed that of rectangular fins beyond this point. For the area goodness factor, their performance was comparable at a Reynolds number of 500, with circular fins outperforming after this point, achieving a 1.8-fold advantage at a Reynolds number of 3000. In terms of the volume goodness factor, both types of fins performed similarly up to a Reynolds number of 1000. Beyond this threshold, circular offset fins demonstrated a 1.3-fold improvement at a Reynolds number of 3000, underscoring the potential of the novel core geometry for compact heat exchanger applications.

Surface Quality Evaluation of 3D-Printed Carbon-Fiber-Reinforced PETG Polymer During Turning: Experimental Analysis, ANN Modeling and Optimization

This work presents an experimental analysis related to 3D-printed carbon-fiber-reinforced-polymer (CFRP) machining. A polyethylene-terephthalate-glycol (PETG)-based composite, reinforced with 20% carbon fibers, was selected as the test material. The aim of the study was to evaluate the influence of cutting conditions used in light operations on the generated surface quality of the 3D-printed specimens. For this purpose, nine specimens were fabricated and machined under a wide range of cutting parameters, including cutting speed, feed, and depth of cut. The generated surface roughness was measured with a mechanical gauge and the acquired data were used to develop a shallow artificial neural network (ANN) for prediction purposes, showing that a 3-6-1 structure is the best solution. Following this, a genetic algorithm (GA) was utilized to minimize the response, revealing that the optimal combination is 205 m/min speed, 0.0578 mm/rev feed, and 0.523 mm depth of cut, contributing to the fabrication of low friction parts and shafts with a high quality surface, as well as to the reduction of resource waste. A validation study supported the accuracy of the developed model, by exhibiting errors below 10%. Finally, a set of enhanced images were taken to assess the machined surfaces. It was found that 1.50 mm depth of cut is responsible for the generation of defects across the circumference of the specimens. Especially, combined with 150 m/min cutting speed and 0.11 mm/rev feed, more flaws are produced.

PTFE-based antistatic coatings by incorporating modified carbon black

A kind of antistatic coatings which were applied to nonconductive surfaces were prepared with Polytetrafluoroethylene (PTFE) as matrix, modified carbon black (CB) as conductive filler. Compared to sodium dodecyl sulfate, poly(vinyl pyrrolidone), the TMN-10 modified CB has better wettability, dispersion, stability and re-disperse. When CBTMN-10content is 5 wt.%, the surface resistivity of coating reach to 106Ω*cm, which denotes the coating performance good antistatic behavior. The antistatic coating of 5 wt.% CBTMN-10content is found to exhibit excellent hydrophobicity and high HV hardness. Meanwhile, the low average friction coefficients and wear rate were achieved in antistatic coating of 5 wt.% CBTMN-10content. Furthermore, compared to MXene, reduced graphene oxide, carbon nanotube, the modified CB as conductive material in PTFE antistatic materials could be an useful way not only excellent properties but also large-scale production as well as a reduction in unit cost in antistatic materials.

A Biomimetic Adhesive Disc for Robotic Adhesion Sliding Inspired by the Net-Winged Midge Larva.

Net-winged midge larvae (Blephariceridae) are known for their remarkable ability to adhere to and crawl on the slippery surfaces of rocks in fast-flowing and turbulent alpine streams, waterfalls, and rivers. This remarkable performance can be attributed to the larvae's powerful ventral suckers. In this article, we first develop a theoretical model of the piston-driven sucker that considers the lubricated state of the contact area. We then implement a piston-driven robotic sucker featuring a V-shaped notch to explore the adhesion-sliding mechanism. Each biomimetic larval sucker has the unique feature of an anterior-facing V-shaped notch on its soft disc rim; it slides along the shear direction while the entire disc surface maintains powerful adhesion on the benthic substrate, just like the biological counterpart. We found that this biomimetic sucker can reversibly transit between "high friction" (4.26 ± 0.34 kPa) and "low friction" (0.41 ± 0.02 kPa) states due to the piston movement, resulting in a frictional enhancement of up to 93.9%. We also elucidate the frictional anisotropy (forward/backward force ratio: 0.81) caused by the V-shaped notch. To demonstrate the robotic application of this adhesion-sliding mechanism, we designed an underwater crawling robot Adhesion Sliding Robot-1 (ASR-1) equipped with two biomimetic ventral suckers. This robot can successfully crawl on a variety of substrates such as curved surfaces, sidewalls, and overhangs and against turbulent water currents with a flow speed of 2.4 m/s. In addition, we implemented a fixed-wing aircraft Adhesion Sliding Robot-2 (ASR-2) featuring midge larva-inspired suckers, enabling transit from rapid water surface gliding to adhesion sliding in an aquatic environment. This adhesion-sliding mechanism inspired by net-winged midge larvae may pave the way for future robots with long-term observation, monitoring, and tracking capabilities in a wide variety of aerial and aquatic environments.

Robust, self-lubricating and injectable dECM-loaded hydrogels based on rapid photo-crosslinking for articular cartilage regeneration

The restoration of articular cartilage poses a significant clinical challenge due to its avascular nature and the limited presence of chondrocytes. Recently, there has been a growing emphasis on developing materials that emulate the properties of cartilage to facilitate high-quality repair. Here, an injectable dECM-loaded hydrogel (HS-dECM) with potent compressive strength and self-lubricating ability was prepared by photo-crosslinking for cartilage regeneration. The HS-dECM hydrogel was formed by integrating cartilage decellularized extracellular matrix (dECM) with hyaluronic acid methacrylate (HAMA) and sulfobetaine methacrylate (SBMA). Once injected into irregular defects, a robust hydrogel was rapidly formed in situ by UV irradiation with negligible heat release. The HS-dECM hydrogel exhibited robust compressive strength (898 ± 86 kPa), excellent fatigue resistance and a low friction coefficient, and had the feasibility of minimally invasive implantation. Besides, HS-dECM hydrogel promoted chondrogenic differentiation of BMSCs in vitro and repaired articular cartilage defects in rats. Therefore, the high-performance injectable HS-dECM hydrogel represents a novel minimally invasive strategy that significantly promote the cartilage injuries repair and regeneration.

Research Progress on Current-Carrying Friction with High Stability and Excellent Tribological Behavior

Current-carrying friction affects electrical contact systems like switches, motors, and slip rings, which determines their performance and lifespan. Researchers have found that current-carrying friction is influenced by various factors, including material type, contact form, and operating environment. This article first reviews commonly used materials, such as graphite, copper, silver, gold, and their composites. Then different contact forms like reciprocating, rotational, sliding, rolling, vibration, and their composite contact form are also summarized. Finally, their environmental conditions are also analyzed, such as air, vacuum, and humidity, on frictional force and contact resistance. Additionally, through experimental testing and theoretical analysis, it is found that factors such as arcing, thermal effects, material properties, contact pressure, and lubrication significantly influence current-carrying friction. The key mechanisms of current-carrying friction are revealed under different current conditions, including no current, low current, and high current, thereby highlighting the roles of frictional force, material migration, and electroerosion. The findings suggest that material selection, surface treatment, and lubrication techniques are effective in enhancing current-carrying friction performance. Future research should focus on developing new materials, intelligent lubrication systems, stronger adaptability in extreme environments, and low friction at the microscale. Moreover, exploring stability and durability in extreme environments and further refining theoretical models are essential to providing a scientific basis for designing efficient and long-lasting current-carrying friction systems.