Ali Erdemir

• Ph.D. in Materials Science and Engineering
• Professor at Texas A&M University

This study explores the impact of a phosphonium-based IL (trihexyltetradecylphosphonium bis(2-ethylhexyl) phosphate, [P6,6,6,14][BEHP])) on the tribological performance of an automatic transmission fluid (ATF) when used as an additive. Tests were carried out under both non-electrified and electrified conditions in a reciprocating ball-on-flat tribo...

Electric vehicles (EVs) have lately seen rapid market growth, aligning well with the green transportation needs of global society. As opposed to the well-established and -addressed tribological issues in traditional internal combustion engine vehicles (ICEV), the tribological challenges in EVs, especially under electrified contact conditions in gen...

Additives play an important role in the tribological performance of lubricants used in internal combustion engine (ICE) vehicles. As we are in the process of rapid transition from ICE vehicles to electric vehicles (EVs), the tribological performance of lubricants under electrified conditions has lately become an important concern since shaft curren...

Considering the growing interest in increasing performance and efficiency of driveline components of modern electric vehicles, this work aims to analyze and report the wear mechanisms and notable enhancement of the lubrication of electrified contact interfaces by inert gas atmospheres. Systematic tribological studies were conducted on AISI 52100 st...

Because of their higher energy efficiency and environmental friendliness, electrical vehicles (EVs) have recently positioned themselves as one of the most sustainable alternatives to traditional combustion engine vehicles. However, there remain numerous challenges (i.e., lubrication, thermal management, electrical compatibility, and corrosion, amon...

Electric vehicles (EVs) represent a new paradigm for a sustainable transportation future with the potential to offer unparalleled energy security, environmental cleanliness, and economic prosperity for all humanity. However, rapid development and adaptation of this new transportation approach depend on addressing multiple challenges, including the...

Friction and wear collectively account for nearly a quarter of the world’s energy consumption, resulting in over eight Gigatons of CO2 emissions annually. With increasing mobility and industrial activity, the adverse effects of friction and wear on energy, the environment, the global economy, and sustainability will undoubtedly intensify. Unless we...

Electric vehicle (EV) mobility represents a transformative shift in achieving better energy security, environmental cleanliness, and economic prosperity. Despite recent advancements in EV technology, several challenges persist in tribology and lubrication fronts that can hamper their long-term reliability, performance, and efficiency. In this work,...

Electric Vehicle Tribology: Challenges and Opportunities for a Sustainable Transportation Future provides practical, comprehensive guidance on a new and increasingly important area of tribology. Building skills from fundamentals to solution design, this book demonstrates the unique tribological techniques essential to the efficient electrification...

Reducing friction and wear in moving mechanical systems is essential for their intended functionality. This is currently accomplished using a large variety of anti-friction and anti-wear additives, that usually contain sulfur and phosphorous both of which cause harmful emission. Here, we introduce a series of diesters, typically dioctyl malate (DOM...

The increasing popularity of electric vehicles as an alternative to internal combustion engine vehicles brings new realities, challenges and opportunities for scientists and engineers. A key element of this transition will be to develop solutions for lubrication, thermal management, electrical compatibility and corrosion inhibition. Two-dimensional...

The need for reliable renewable energy storage devices has become increasingly important. However, the performance of current electrochemical energy storage devices is limited by either low energy or power densities and short lifespans. Herein, we report the synthesis and characterization of multilayer Ti4N3Tx MXene in various aqueous electrolytes....

EV Lubricants are required to fulfill different functional requirements, namely, suitable electrical, thermal, tribological and chemical properties, E-motor material compatibility and eco-friendliness. Considering the state-of-the-art on the progress of biodegradable or bio-based lubricants, fluid formulations containing biodegradable oils such as...

The increasing worldwide demand for hybrid and electric vehicle technology has brought new challenges for the global lubricant industry. The new lubricants for electric vehicles, also called E-fluids or EV-fluids, are expected to meet a new set of requirements including withstanding the much severe operating conditions of EV powertrains. High start...

Electrification of drivelines of electric vehicles (EVs) can give rise to damaging shaft voltages/currents that can potentially impair the tribological performance of sliding and rolling elements in these driveline systems. In fact, previous research has shown that the existence of shaft voltages/currents in electric machines is indeed highly detri...

In automotive industry, most of the moving components and lubricants are currently being reengineered in order to meet the much harsher operating conditions of electric vehicles (EVs). Diamond-like carbon (DLC) coatings have been widely used in automotive field mainly because of their lower friction and wear coefficients, high chemical inertness, c...

In electric vehicles´ powertrains, bearings can be susceptible to failure more rapidly than some of the other components mainly because of accelerated fatigue, corrosion and wear. Specifically, due to much severe operating conditions (including high speeds, torques, temperatures) of such vehicles combined with the presence of an electrical environm...

Superlubricity is a terminology often used to describe a sliding regime in which the adhesion leading to friction or resistance to sliding literally vanishes. For improved energy security, environmental sustainability, and a decarbonized economy, achieving superlubric sliding surfaces in moving mechanical systems sounds very exciting, since frictio...

Electrification of electric vehicles’ drivetrains can give rise to damaging shaft voltages and currents that can impair the long term tribological performance of critical components (i.e. bearings, gears, etc.) resulting from electrical discharges at sliding interfaces. Particularly, gears are used in drivetrain architectures comprising electric mo...

The Cover Feature shows a mixed waste plastic stream being converted to synthetic motor oil lubricants. A Pt nanoparticle catalyst utilizes H2 gas to selectively break up the hydrocarbon chains via C−C scissions to produce a liquid, monodisperse product. More information can be found in the Full Paper by R. A. Hackler et al.

The energy efficiency, mechanical durability, and environmental compatibility of all moving machine components rely heavily on advanced lubricants for smooth and safe operation. Herein an alternative family of high‐quality liquid (HQL) lubricants was derived by the catalytic conversion of pre‐ and post‐consumer polyolefin waste. The plastic‐derived...

Surface-modified CaCO3 nanoparticles, synthesized through plasma-enhanced chemical vapor deposition (PECVD), were employed to improve lubricant additive technology for internal combustion engines via reduction and/or replacement of additives, such as zinc dialkyl dithiophosphate (ZDDP), in engine oil. Various oil formulations were prepared with fun...

The development of low phosphorus engine oils is important to minimize phosphorus-induced exhaust catalyst poisoning and resulting in harmful emissions. In this study, low phosphorus oil formulations were prepared by using an ashless additive mixture of borate ester (SB) with ionic liquid composed of a phosphonium cation and phosphate anion (P_DEHP...

Surface-modified CaCO 3 nanoparticles, synthesized through plasma-enhanced chemical vapor deposition (PECVD), were employed to improve lubricant additive technology for internal combustion engines via reduction and/or replacement of additives, such as zinc dialkyl dithiophosphate (ZDDP), in engine oil. Various oil formulations were prepared with fu...

Surface-capped zinc oxide (ZnO) nanoparticles were engineered to deliver beneficial anti-wear and anti-friction chemistries at sliding interfaces with a focus on potentially reducing environmentally hazardous zinc dialkyl dithiophosphate (ZDDP) additive in automotive lubricants, without compromising tribological performance. A plasma polymerization...

This work reports on the development of borate- and methacrylate-polymer-coated zinc oxide nanoparticles (ZnOBM) via a plasma polymerization technique to replace the harmful conventional antiwear additive zinc dialkyl dithiophosphate (ZDDP) in automotive lubricants. Here, the tribochemistry across the interfaces formed between sliding ferrous surfa...

Tribochemistry involves chemical reactions occurring at sliding contact interfaces in the presence of gaseous and/or liquid media. It often leads to the formation of a solid reaction film (also referred to as boundary film) which controls friction and wear, and hence the efficiency and reliability of moving mechanical systems (such as engines). Her...

Layered double hydroxides (LDHs) have lately been hailed as robust lubricant additives for improving tribological properties, and as ideal catalysts for synthesizing carbon-based nanomaterials. In this paper, in-situ analytical tools are used to track the evolution of the crystal structure and chemical composition of LDHs during calcination. Nickel...

Any moving mechanical system consisting of sliding/rolling or rotating interfaces experiences friction and wear. High contact pressure and shear during relative movement of the sliding interfaces in the presence of lubricants often lead to interesting tribochemical activity at nanoscale, which then greatly influences the tribological performance of...

In this study, ultralow friction coefficient (COF, μ < 0.01) was obtained through polyalkylene glycol (PAG) aqueous solutions with different molecular weights (MWs) ranging from 270 to 3930 g·mol-1 under ambient conditions. With increases in the MWs of PAG molecules, the threshold concentration to obtain this type of superlubric behavior gradually...

Tribochemical interaction of zinc dialkyl dithiophosphate (ZDDP) with titanium dioxide nanoparticles and plasma functionalized TiO2, to ascertain their synergist effects on tribological performance of steel test pairs under boundary lubricated sliding conditions in a mineral base oil, was investigated. A pin on reciprocating flat test configuration...

In this study, interaction of ionic liquid (IL) and borate esters (SBs) as antiwear (AW) additives with steel surfaces in tribological contacts was examined using blends which contained no prior AW additives but all the other ingredients present in a fully formulated engine oil. In detail, low phosphorus oil blends were prepared by adding trihexylt...

Growing concerns over energy and environmental sustainability have lately sparked worldwide interest in more efficient and cleaner transportation systems and industrial activities. Friction roughly consumes one-fifth of all energy used worldwide. One-third of all energy used in transportation goes to overcome friction. At the same time, the fruits...

Diamond-like carbon (DLC) is a class of amorphous carbon materials used as wear-resistant coatings in tribo-components. The chemical inertness of DLC surfaces, while important in many applications, makes them incompatible with additives in commercial lubricants. Specifically, DLC surfaces do not permit strong adsorption of friction modifier molecul...

Vanadium oxide (V2O5) is one of the lubricious oxides with the potential to be used as a solid lubricant at elevated temperatures. However, the material itself is not hard wear-resistant, so most of the research has focused on adding V into hard nitride coatings that could lead to the formation of a self-lubricating V2O5 layer when heated. The othe...

Stress-induced reactions at the sliding interface during relative movement are known to cause structural or chemical modifications in contacting materials. The nature of these modifications at the atomic level and formation of byproducts in an oil-free environment, however, remain poorly understood and pose uncertainties in predicting the tribologi...

Controlling friction in and reducing wear of moving mechanical systems are great challenges in many applications, from nanoscale electromechanical systems to large-scale car engines and wind turbines. Accordingly, multiple efforts are dedicated to designing new materials and surfaces for efficient friction and wear manipulation. Recent advances in...

The demand for increased energy efficiency continuously drives the development of new lubricants. Here we report the design and synthesis of hexahydrotriazine, triazine, and cyclen derivatives as friction modifiers (FMs) for enhanced fuel economy. This series of sulfur- and phosphorus-free oil-soluble heterocyclic ring-based molecules exhibits diff...

Polyalkylene glycols (PAG) have been explored as a possible base stock for engine oil formulation. Friction, wear, and load carrying capacity of five different PAG chemistries were evaluated either as base stock or as formulated oils in pure sliding and sliding/rolling conditions using various laboratory bench test rigs operating under boundary and...

Ultralow friction is achieved by ZrO2 as the friction mate material for DLC (Diamond like carbon) films under various environments. Coefficient of friction (CoF) of ZrO2/DLC films is as ultra low as 0.02 in ambient air at the temperature of 200 °C, and 0.03, 0.04 and 0.05 in hydrogen, nitrogen and vacuum environments at the temperature of 100 °C, r...

In total, ~23% (119 EJ) of the world’s total energy consumption originates from tribological contacts. Of that 20% (103 EJ) is used to overcome friction and 3% (16 EJ) is used to remanufacture worn parts and spare equipment due to wear and wear-related failures.

Layered double hydroxides (LDHs) are a class of naturally-occurring inorganic minerals which are composed of divalent and trivalent metal cations. In this study, three different sized NiAl-LDH nanoplatelets were synthesized by varying crystallization time during the micro-emulsification process. The layered structure and three-dimensional size of n...

Plasma functionalized poly tetra fluoroethylene (PTFE) nanoparticles were employed to evaluate their utility in improving the lubrication property of a group III mineral oil with significantly low amount of zinc dialky dithiophosphate (ZDDP). The particles were coated with two consecutive films, the initial coating contained silica to enhance amorp...

Calculations on the global energy consumption due to friction and wear in the mineral mining industry are presented. For the first time, the impact of wear is also included in more detailed calculations in order to show its enormous tribological and economic impacts on this industry. A large variety of mining equipment used for the extraction, haul...

This paper presents an experimental study of friction and wear performance of quaternary CrSiCN coatings deposited on a hardened H-13 steel substrate by a plasma enhanced magnetron sputtering (PEMS) technique. Friction and wear tests were conducted with a reciprocating line contact between a hardened 4370 steel roller and coated and uncoated flat s...

The paper reports the operando and self-healing formation of DLC films at sliding contact surfaces by the addition of synthetic magnesium silicon hydroxide (MSH) nanoparticles to base oil. The formation of such films leads to a reduction of the coefficient of friction by nearly an order of magnitude and substantially reduces wear losses. The ultral...

Changing the surface texture of sliding surfaces is an effective way to manipulate friction and wear of lubricated surfaces. Having realized its potential, we have done very extensive studies on the effects of laser surface texturing (LST, which involves the creation of an array of microdimples on a surface) on friction and wear behavior of oil-lub...

Boron based compounds have been studied for decades due to their unusual anti-friction and -wear characteristics. In particular, hexagonal boron nitride (h-BN), boric acid, and boron oxide are good solid lubricants and used in a variety of tribological applications. Nanoparticulate h-BN and boric acid as well as borate esters and boron-based ionic...

Hydrogenated diamond like Carbon (H-DLC) is a promising lubricious coating that attracted a great deal of interest in recent years mainly because of its outstanding tribological properties. In this study, the nano-mechanical and -tribological properties of a range of H-DLC films were investigated. Specifically, four kinds of H-DLC coatings were pro...

In this study, we mainly focus on the structural morphology and inter-atomic bonding state of tribofilms resulting from a highly-hydrogenated amorphous carbon (a-C:H) film in order to ascertain the underlying mechanisms for its superlubric behavior (i.e., less than 0.01 friction coefficient). Specifically, we achieved superlubricity (i.e., friction...

Hydrophobicity and humidity tolerance of the low friction behavior of hydrogenated diamond-like carbon (H-DLC) were improved via surface modification using vapor-phase chemical reactions with organic silanes at 250–280 °C. Water and hexadecane contact angles increased after silane treatments. Unlike pristine H-DLC which loses ultra-low friction beh...

Moving mechanical interfaces are commonly lubricated and separated by a combination of fluid films and solid 'tribofilms', which together ensure easy slippage and long wear life. The efficacy of the fluid film is governed by the viscosity of the base oil in the lubricant; the efficacy of the solid tribofilm, which is produced as a result of sliding...

This study investigates the rheological properties, elastohydrodynamic (EHD) filmforming capability, and friction coefficients of low molecular mass poly-A-olefin (PAO) base stocks with varying contents of high molecular mass olefin copolymers (OCPs) to assess their shear stability and their potential for energy-efficient lubrication. Several PAO-O...

Synergistic interaction between ionic liquids (ILs) and soluble borate (SB) esters were examined in the context of tribofilm formation for antiwear applications. ILs composed of phosphonium cation and phosphate anion (P_DEHP) and dithiophosphate anion (P_DEPDT), respectively, were mixed with borate esters in group I base oil at 1000 P ppm and 200 B...

The effects of oxidation on wear of carbon/steel tribological interfaces were studied. When mechanical wear was small, the oxidation behavior of hydrogenated diamond-like carbon (H-DLC) and stainless steel (SS) sliding interface varied depending on the nature of the oxidizing environment. In dry air or oxygen, both H-DLC and SS wore readily. The we...

The growing demands for renewable energy production have recently resulted in a significant increase in wind plant installation. Field data from these plants show that wind turbines suffer from costly repair, maintenance and high failure rates. Often times the reliability issues are linked with tribological components used in wind turbine drivetrai...

Superlubricity is defined as a sliding regime in which friction or resistance to sliding almost vanishes. While there are a number of superlubricity, providing a high temperature superlubricity remains a challenge. Here we present a high temperature superlubricity achieved from the diamond like carbon (DLC) films friction system. Superlubricity is...

Compositionally graded and non-graded composite SiCu thin films were deposited by magnetron sputtering technique on Cu disks for investigation of their potentials in lithium ion battery applications. The compositionally graded thin film electrodes with 30 at.% Cu delivered a 1400 mAh g− 1 capacity with 80% Coulombic efficiency in the first cycle an...

Friction and wear remain as the primary modes of mechanical energy dissipation in moving mechanical assemblies, thus it is desirable to minimize friction in a number of applications. We demonstrate that superlubricity can be realized at engineering scale when graphene is utilized in combination with nanodiamond particles and diamond-like carbon (DL...

A method of ultra-fast boriding of a metal surface. The method includes the step of providing a metal component, providing a molten electrolyte having boron components therein, providing an electrochemical boriding system including an induction furnace, operating the induction furnace to establish a high temperature for the molten electrolyte, and...

Mixtures of zinc dialkyl dithiophosphates (ZDDP) and ashless fluorothiophosphates and thiophosphates were examined under tribological conditions. The tribofilms were studied using nano-indentation, electron microscopy and X-ray absorption near edge structure spectroscopy. With the addition of ashless fluorothiophosphates and thiophosphates, there i...

The oxidized layers at the surface of hydrogenated diamond-like carbon (H-DLC) were studied with x-ray photoelectron spectroscopy, near-edge x-ray absorption fine structure, and Raman spectroscopy. The structure of these layers was correlated with the friction and wear behavior observed on H-DLC. H-DLC is well known for its ultra-low friction in in...

Poor or inefficient lubrication often gives rise to high friction and wear losses in machine components, which adversely affect their performance, efficiency, and durability. Many approaches are being explored to enhance the antifriction and antiwear properties of sliding machine components. In this study, the antifriction and antiwear properties o...

In this study, molybdenum plates (99·5% purity) were subjected to electrochemical boriding in a molten borax electrolyte in order to synthesise molybdenum boride phases on exposed surfaces. Electrochemical boriding was carried out at temperatures of 900, 950 and 1000°C for a duration of 30–180 min at a current density of 0·5 A cm−2. Cross-sectional...

In this study, molybdenum plates (99·5% purity) were subjected to electrochemical boriding in a molten borax electrolyte in order to synthesise molybdenum boride phases on exposed surfaces. Electrochemical boriding was carried out at temperatures of 900, 950 and 1000°C for a duration of 30-180 min at a current density of 0·5 A cm-2. Cross-sectional...

Worldwide about 100 million terajoule is used annually to overcome friction and that is one fifth of all energy produced. The largest quantities of energy are used by industry (29 %) and in transportation (27 %). Based on our recent studies on energy use in passenger cars, trucks and buses, we concluded that it is possible to save as much as 17.5 %...

During the past two decades, global awareness and societal needs for more fuel-efficient and environmentally friendly transportation systems have increased considerably because of the diminishing oil reserves, skyrocketing fuel prices, and much tougher governmental regulations to combat greenhouse gas emissions. During the same period, automotive a...

This book describes current, competitive coating technologies for vehicles. The authors detail how these technologies impact energy efficiency in engines and with increased use of lightweight materials and by varying coatings applications can resolve wear problems, resulting in the increased lifecycle of dies and other vehicle components.

Potential for graphene to be used as a lubricant for sliding electrical contacts has been evaluated. Graphene, being deposited as a sporadic flakes on the gold substrate sliding against titanium nitride ball shows not only significant improvement in tribological behavior by reducing both friction (by factor of 2–3) and wear (by 2 orders) but also,...

Achieving superlow friction and wear at the micro/nano-scales through the uses of solid and liquid lubricants may allow superior performance and long-lasting operations in a range of micromechanical system including micro-electro mechanical systems (MEMS). Previous studies have indicated that conventional solid lubricants such as highly ordered pyr...

Friction and triboelectrification of materials show a strong correlation during sliding contacts. Friction force fluctuations are always accompanied by two tribocharging events at metal–insulator [e.g., polytetrafluoroethylene (PTFE)] interfaces: injection of charged species from the metal into PTFE followed by the flow of charges from PTFE to the...

Friction and triboelectrification of materials show a strong correlation during sliding contacts. Friction force fluctuations are always accompanied by two tribocharging events at metal–insulator [e.g., polytetrafluoroethylene (PTFE)] interfaces: injection of charged species from the metal into PTFE followed by the flow of charges from PTFE to the...

Friction force fluctuations are accompanied by two tribocharging events: the flow of charged species in one direction promptly followed by the flow of charges in the reverse direction. T. A. L. Burgo and A. Erdemir describe in their Communication on page 12101 ff. that owing to mechanochemical reactions, a microscopically high-energy non-equilibriu...

Reibungskraftfluktuationen gehen mit zwei Triboladungsvorgängen einher: dem Fluss von geladenen Teilchen in die eine Richtung, unmittelbar gefolgt von dem Fluss von Ladungen in die andere Richtung. T. A. L. Burgo und A. Erdemir beschreiben in ihrer Zuschrift auf S. 12297 ff., wie mechanochemische Reaktionen einen mikroskopisch stationären Hochenerg...

During the last few years, graphene's unusual friction and wear properties have been demonstrated at nano to micro scales but its industrial tribological potential has not been fully realized. The macroscopic wear resistance of one atom thick graphene coating is reported by subjecting it to pin-on-disc type wear testing against most commonly used s...