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The exploration of high-performance coatings is specifically necessary for enhancing the mechanical, thermal, and corrosion-resistant characteristics of structural steels in response to the demand for cutting-edge materials in engineering applications. The current study addresses an existing void in the development of durable coatings that gain benefits from the distinctive characteristics of CoCrFeNiCu high entropy alloys (HEA) for stainless steel substrates, with a particular emphasis on SS 304. The primary objective was to examine the microstructural, mechanical, and corrosion behaviors of SS 304 that had been coated with CoCrFeNiCu HEA employing a microwave cladding process. HEA particles were prepared through mechanical milling, and a controlled cladding process was conducted under an inert environment. A variety of meticulous investigations, including Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and wear rate measurements, have been performed to thoroughly assess crucial parameters, including surface hardness, resistance to corrosion, and wear behavior. This study explores the influence of a CoCrFeNiCu high entropy alloy (HEA) coating (20 % each component) on SS-304 steel. Utilizing microwave cladding, the coating demonstrated a substantial impact on wetting behavior, interfacial microstructure, hardness, and corrosion resistance. Surface hardness was substantially enhanced by the cladding process, resulting in a 54.76 % rise from 210 HV to 325 HV. This enhancement substantially raised the mechanical strength of the steel. Under 120 h of corrosion testing in 3.5 wt.% NaCl, a minimal weight loss of 0.342 mg was observed, suggesting that the material exhibited substantial corrosion resistance. In addition, the material’s capacity to resist abrasive forces has been demonstrated by the relatively minimal wear rate of 0.0012 mm3/m that was noticed throughout wear resistance experiments. Effective interfacial adhesion, bonding strength, and uniform distribution were observed by the coating, which resulted in enhanced mechanical characteristics and durability in harsh circumstances. Wetting characteristics indicated enhanced hydrophobicity/hydrophilicity compared to the uncoated surface. SEM images displayed a well-adhered, homogeneous interfacial region, signifying a robust metallurgical bond. The cladding surface exhibited a uniform distribution of CoCrFeNiCu HEA particles. Notably, the steel’s surface hardness increased by approximately 54.76 % postdeposition. These findings underscore the potential of CoCrFeNiCu HEA coatings in advancing steel surface properties for improved performance and durability. The potential of CoCrFeNiCu HEA coatings to enhance the performance and longevity of SS 304 steel in chemical, marine environments, etc., applications that necessitate superior resistance to wear, protection against corrosion, and structural or mechanical integrity is underscored by these findings. [ABSTRACT FROM AUTHOR]

Laser cladding technology is an efficient method for repairing downhole drilling tools. The microstructural evolution and tribo-corrosion mechanism of Ni-WC laser-clad coating were investigated. The microstructural results indicate that the Ni-WC laser-clad coating is mainly composed of γ-Ni, WC, W2C, MxCy (M = W, Ni, Cr, Fe, Mo), M23C6 (M = W, Ni, Cr, Fe, Mo), and eutectic phases (CrC / MoC). Cl− exacerbates the corrosion of MxCy layer around WC particles by penetrating cracks, which further causes the shedding of the MxCy layer during wear. During tribo-corrosion, the Ni-WC laser-clad coating's open-circuit potential shifts negatively with increasing loads. Meanwhile, Ecorr shifted negatively and Icorr gradually increased, indicating more severe corrosion promoted by wear. The wear rate of coating is higher under open-circuit potential compared to that under pure mechanical wear, and mechanical wear is predominant in tribo-corrosion. [ABSTRACT FROM AUTHOR]

Given its good processing nature and antifatigue performance, 20CrMnTi alloy steel has been widely applied in the gear manufacturing field of engineering machinery. Actual service situations show that the inevitable friction, wear, and corrosion behavior have seriously affected its service performance. Laser shock peening technology could quickly and efficiently improve the mechanical properties and corrosion resistance performance of the surfaces of many metallic materials. This study systematically investigated the effect of different laser energies on the corrosion resistance of 20CrMnTi steel after fretting wear. Results showed that the laser shock-peened 20CrMnTi alloy exhibited better tribology and electrochemical corrosion resistance than the substrate, attributing to its surface microstructure and mechanical properties had been improved. [ABSTRACT FROM AUTHOR]

This study aims to achieve in situ-formed pure Ti and Ti6Al4V coatings on 316L stainless steel through hot pressing and examine their wear and corrosion properties thoroughly in two simulated body fluids: physiological serum (0.9% NaCl) and Hanks' solution. The sintering and diffusion bonding process was conducted at 1050 °C under a uniaxial pressure of 40 MPa for 30 min in a vacuum environment of 10−4 mbar. Following sintering, in situ-formed pure Ti and Ti6Al4V coatings, approximately 1000 µm thick, were produced on 316L substrates approximately 3000 µm in thickness. The mean hardness of 316L substrates, pure Ti, and Ti6Al4V coatings are around 165 HV, 170 HV, and 420 HV, respectively. The interface of the stainless steel substrate and the pure Ti and Ti6Al4V coatings exhibited no microstructural defects, while the interface exhibited significantly higher hardness values (ranging from 600 to 700 HV). The coatings improved corrosion resistance in both electrolytes compared to the 316L substrate. Wet wear tests revealed reduced friction coefficients in 0.9% NaCl relative to Hanks' solution, highlighting the chemical interactions between the material surface and the electrolyte type and the significance of tribocorrosion in biocoatings. [ABSTRACT FROM AUTHOR]

The corrosive nature of ionic liquids (ILs) limits their potential as high-performance conductive lubricants in practical engineering applications. This study systematically investigates the effects of benzotriazole (BTA) as a corrosion inhibitor on the lubricating performance of ILs at different concentrations and applied currents, along with the underlying mechanisms. In the 0.5–5 A current range, BTA effectively reduces friction, wear, and arc erosion damage to the friction surface. As the applied current increases, the BTA-Fe reaction film suppresses oxide formation, thereby reducing electrical contact resistance (ECR). Moreover, the effectiveness of BTA is concentration-dependent: at 0.5 A and a BTA concentration of 0.5 wt%, the coefficient of friction (COF) decreases by 16.5%, and wear volume is reduced by 53.4%. Friction testing and surface analysis show that the BTA-IL combination exhibits synergistic lubrication and anti-corrosion effects under current-carrying conditions, with varying wear and lubrication mechanisms depending on the applied current. [ABSTRACT FROM AUTHOR]

Micro arc oxidation (MAO) played a positive role in surface modification treatment of magnesium alloys (MAs), and their hardness was further improved, which could be applied in aerospace, automotive industry and biomedical fields. In this study, oxide coatings were form on AZ31B MA using MAO with the different voltages. The influence of voltage on the microstructure, tribocorrosion and electrochemical properties of obtained coatings was investigated, and the wear and corrosion mechanisms were also discussed in detail. The results show that the MAO coatings are composed of MgO and Mg2SiO4 phases, and their thicknesses, surface roughness and nanohardness are increased with the voltage, which are depended on the reactions of MAO. The average COFs and wear rates of MAO coatings are decreased with the voltage, presenting the superior friction reduction and wear resistance. The wear mechanism of MAO coatings is abrasive wear and oxidative wear, which is attributed to the increase of hardness by the MAO process. The corrosion current density of MAO coating fabricated at 410 V is lower 1 to 2 orders than those of other MAO coatings, showing the best corrosion resistance. Moreover, the Rct of MAO coating fabricated at 410 V is the maximum, and its NA is the minimum, showing the best corrosion resistance. [ABSTRACT FROM AUTHOR]

Diamond-like carbon coatings can be used to protect precision components in extreme marine environments from the coupling effects of tribocorrosion. However, the thickness of the diamond-like carbon coating is limited by residual stress. In this paper, a method combining filtered cathodic vacuum arc deposition and high-voltage pulsed technology is used to controllably release residual stresses to deposit high-quality thick diamond-like carbon coatings and to study their tribocorrosion mechanism and performance in extreme environments. The results showed that periodic energetic particles could disrupt the local carbon network structure with increasing frequency, thereby reducing the residual stress to 0.787 GPa in a diamond-like carbon coating of about 5 μm, and the release of residual stress prevented the formation of corrosion channels during corrosion of the diamond-like carbon coating. The high-quality diamond-like carbon coating was tested in a tribocorrosion test at 5 N and 10 N loads. The excellent corrosion resistance reduces the coupling effect of tribocorrosion on the coating. The high content of graphite-like structures inhibits the formation of microcracks, reducing the degree of wear of the diamond-like carbon coating in 3.5 wt% NaCl solution. The combination of high-voltage pulsed technology and filtered cathodic vacuum arc deposition can break through the limitation of residual stress on the thickness of diamond-like carbon coatings, which provides meaningful guidance for the application of thick diamond-like carbon coatings for surface protection of precision devices. [ABSTRACT FROM AUTHOR]

Lightweight aluminum alloy is one of the widely used structural materials for various industries due to its low density, high strength-to-weight ratio, good corrosion resistance, and excellent recyclability. However, complex service conditions often result in material degradation due to simultaneous mechanical and corrosion attacks on the metal surfaces, such as tribocorrosion. This phenomenon represents a complex multiphysics challenge, wherein the tribocorrosion-induced material loss emerges as a function of varied environmental, mechanical, and electrochemical descriptors, each entailing distinct yet interlinked physical processes. The pursuit of simultaneous optimization across multiple material properties to enhance the overall tribocorrosion resistance is hampered by the inherent trade-offs between wear and corrosion resistance. Addressing this complexity, our study develops a novel methodology fusing machine-learning (ML) and genetic algorithm (GA)-based optimization techniques to tailor aluminum-based alloys for enhanced tribocorrosion resistance. Leveraging an experimentally validated multiphysics finite element analysis (FEA) model, we have used six key material parameters to model the tribocorrosion performance of Al alloys over a large property space. The ML model employs an ensemble method of artificial neural networks (ANNs) to predict the tribocorroded surface profile and total material loss based on FEA simulation results, significantly reducing computational time compared to conventional FEA methods. Crucially, our high-throughput screening pinpoints corrosion current density and yield strength as two pivotal parameters influencing tribocorrosion behavior. Harnessing GA optimization alongside the ML model, we efficiently identify a suite of optimal material properties—encompassing both mechanical and electrochemical aspects—for aluminum alloys, resulting in superior tribocorrosion resistance. This selection is substantiated through validation against high-fidelity FEA simulation results. This data-driven framework holds promise for tailoring tribocorrosion-resistant materials beyond aluminum alloys, adaptable to a wide range of metals and service environments. [ABSTRACT FROM AUTHOR]

Chemical mechanical planarization (CMP) is a technique used to efficiently prepare defect-free, flat surfaces of stainless steel (SS) foils and sheets that are implemented in various modern devices. CMP uses (electro)chemical reactions to structurally weaken the surface layers of a workpiece for easy removal by low-pressure mechanical abrasion. Using a model CMP system of 316/316L stainless steel (SS) in an acidic (pH = 3.63) slurry with alumina abrasives, citrate buffer (CB), and H2O2, we examine the tribo-electrochemical mechanisms of SS CMP that dictate the designs of functionally efficient and cost-effective CMP slurries. The use of CB as a pH-controlled complexing agent prevents defect-causing dissolution of SS and eliminates the need for using separate (often toxic) corrosion inhibitors in the slurry. A material removal rate of 8.6 nm min−1 is obtained at a moderate down pressure of 0.014 MPa with a platen rotation speed of 95 RPM. Electrochemical techniques are strategically combined with mechanical abrasion of SS test samples to probe complex CMP mechanisms that are not readily accessible with electrochemical experiments alone. Corrosion-like reactions of salt-film formation at the SS surface act to enable the CMP process, where corrosion-induced wear plays a major role in material removal. [ABSTRACT FROM AUTHOR]

Most of the reported corrosive-wear or tribocorrosion tests have been carried out using an inert and insulating counter-body in the experimental set up, with the purpose of eliminating the direct contribution of the counter-body to the electrochemical response during sliding wear. Little work has been reported using the same material as the test specimen and as the counter-body. In this work, corrosive-wear experiments have been carried out on the same material contact, i.e., stainless steel on stainless steel (SS-SS), where a 316 SS specimen was sliding against a 316 SS slider in 0.5 M NaCl solution under controlled electrochemical conditions. For comparison purpose, similar experiments have also been conducted on the 316 SS-Al2O3 sliding pair. The tests were conducted under reciprocating sliding conditions at 1 Hz frequency, 4 N load and for a duration of 7200 s, incorporated with electrochemical control which included potentiodynamic polarization and potentiostatic polarization at constant negative and positive potentials with respect to the open circuit potential. The results show that the counter-body has a large effect on the corrosive-wear behaviour of the 316 SS specimen under all test conditions. As compared to the SS-Al2O3 sliding pair, the SS-SS pair experiences larger material removal from the specimen. Adhesive wear occurs in the SS-SS pair which leads to significantly roughened sliding surfaces and unstable frictional behavior and electrochemical response. Further analysis revealed that mechanical wear plays a more dominant role in material removal in the SS-SS pair than in the SS-Al2O3 pair, and it is the corrosion-accelerated wear that contributes to the significantly increased material removal in the SS-SS pair. [ABSTRACT FROM AUTHOR]

High-entropy alloy (HEA) coatings have attracted wide scientific attention in academic research and industrial innovation. In the present paper, the NiCoCrAlY HEA coatings are successfully synthesized on the surface of M50 steel to improve the corrosion resistance and tribocorrosion resistance of M50 steel in salt-contaminated lubricating oil. The corrosion and tribocorrosion behaviors of M50 steel and NiCoCrAlY coatings are studied systemically under the same conditions. The experimental results show that NiCoCrAlY coatings have good, densified microstructures and improve effectively the corrosion resistance and tribocorrosion resistance of M50 steel because the protective passivation films and oxide films are formed on the surface of NiCoCrAlY coatings. NiCoCrAlY coatings have high corrosion potential, a low corrosion current density, and a corrosion rate that is comparable with M50 steel. The corrosion potential of M50 steel decreases and the corrosion current density increases with the increase in load due to wear-induced corrosion. The corrosion and tribocorrosion mechanisms of M50 steel and coatings are discussed in light of the experimental results. The wear mechanism of M50 steel is abrasive wear. It is accompanied by corrosion wear for M50 steel and oxidative wear for NiCoCrAlY coatings. [ABSTRACT FROM AUTHOR]

Ti6Al4V alloy–CoCrMo alloy pair is commonly applied for modular head–neck interfaces for artificial hip joint. Unfortunately, the fretting corrosion damage at this interface seriously restricts its lifespan. This work studied the fretting corrosion of Ti6Al4V–CoCrMo pair in calf serum solution. We established this material pair's running condition fretting map (RCFM) regarding load and displacement, and revealed the damage mechanism of this material pair in various fretting regimes, namely partial slip regime (PSR), mixed fretting regime (MFR), and gross slip regime (GSR). The damage mechanism of Ti6Al4V alloy was mainly abrasive wear induced by CoCrMo alloy and tribocorrosion. Adhesive wear (material transfer) also existed in MFR. The damage mechanism of CoCrMo alloy was mainly abrasive wear induced by metal oxides and tribocorrosion in GSR and MFR, while no apparent damage in PSR. Furthermore, a dense composite material layer with high hardness was formed in the middle contacting area in GSR, which reduced the corrosion and wear of Ti alloys and exacerbated damage to Co alloys. Finally, the ion concentration maps for Ti and Co ions were constructed, which displayed the transition in the amount of released Ti and Co ions under different displacements and loads. [ABSTRACT FROM AUTHOR]

Compared with traditional Ti-based biomaterials, in recent years Cu-bearing titanium alloys have been considered among the most attractive metallic biomaterials for oral implants, owing to their excellent antibacterial properties. In this paper, the effects of the Cu content, the existing form of Cu element, and the oral environment on the tribocorrosion resistance of Ti-Cu alloys were investigated in comparison with pure titanium (cp-Ti). The results revealed that a low pH and (especially) a high fluoride ion concentration accelerated the tribocorrosion. The Ti-Cu alloys showed a higher tribocorrosion resistance than cp-Ti in all the simulated solutions tested, owing to the precipitation of nano-Ti2Cu during the aging treatment. [ABSTRACT FROM AUTHOR]

The study involved the preparation of mixtures of phytic acid ionic liquid and water, which were analyzed for their rheological, frictional, and electrochemical properties. The viscosity and friction characteristics of the mixtures are significantly affected by the water content. Mixtures with low water content (below 30%) result in low friction and negligible wear because of the generation of a close adsorption film and high viscosity. Especially, steel tribo-pairs lubricated with mixtures containing 25% water exhibited friction coefficients lower than 0.06. However, when the water content exceeds 35%, the friction coefficient increases dramatically, and the tribo-surface suffers from severe corrosive wear due to the predominance of tribocorrosion in the frictional properties. These results were confirmed through XPS and electrochemical testing. [ABSTRACT FROM AUTHOR]

This review covers the literature that is currently accessible, as well as emerging research into the performance of NiTi-based alloys exposed to corrosive environments in both engineering and medical applications. It provides an overview of the state-of-the-art research in the study of tribocorrosion of Ni-rich NiTi alloy by highlighting significant discoveries, research approaches, and future research directions following the limited reviews on tribocorrosion in the past decade. The practical impacts, as well as the economic implications of tribological applications on daily life, coupled with the increasing failures of metals and biomaterials, make it imperative to investigate tribocorrosion and update the subject area on the recent focus. Tribocorrosion is commonly observed on the surface of different metals, including NiTi alloys, such as NiTiNOL60 (60 wt.% Ni and 40 wt.% Ti), which possess unique properties applicable across various engineering and biomedical fields. In its application, the material experiences wear due to the depassivation of tribofilms caused by relative motion (sliding, fretting, or impact) in aggressive environments, including corrosive mediums, high temperatures, and pressures. This study elucidates the synergistic interactions between mechanical wear, corrosion, and their associated tribocorrosion mechanisms in corrosive media. [ABSTRACT FROM AUTHOR]

This study presents an investigation into the tribological, corrosion, and tribocorrosion properties of AISI 316Ti (austenitic) and AISI 430 (ferritic) stainless steels. The comparative analysis focuses on microstructural characterization, hardness, and a series of tribological, electrochemical, and tribocorrosion tests conducted in 0.9% NaCl using a specialized linear tribometer to reveal the quality of the studied materials in tribocorrosion applications. Friction tests were performed under both dry and corrosive conditions, while tribocorrosion tests were conducted under open circuit potential (OCP) conditions in 0.9% NaCl, with the electrode potential of the test specimen monitored during friction. To evaluate the electrochemical behavior of the materials, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) were conducted using a 0.9% NaCl solution. The measured corrosion potential (Ecorr) suggests that AISI 430 is thermodynamically more stable than AISI 316Ti; however, AISI 316Ti demonstrated higher polarization resistance (RP) values compared to AISI 430. The findings indicate that material qualities significantly influence the coefficient of friction (CoF). Additionally, a notable antifriction effect of 0.9% NaCl was observed during tribological testing, resulting in a lower CoF compared to dry friction conditions. A cathodic shift in OCP during tribocorrosion testing was also observed in both materials, indicating an increase in corrosion vulnerability when the passive layer is degraded. [ABSTRACT FROM AUTHOR]

This paper investigates the flow structures and wear characteristics of solid–liquid two-phase flow in a centrifugal pump under stall conditions using the numerical method. The Computational Fluid Dynamics-Discrete Element Method coupling approach is employed to model the particle–particle and particle–liquid interactions; furthermore, the entropy theory is utilized to evaluate the energy loss and Erosion-Corrosion Research Center model is used to predict wear characteristics. The results indicate that compared to the critical stall condition, deep stall condition leads to a significant increase in the number and size of stall vortices within the impeller channel, which results in a 22% increase in channel blockage and a more uneven particle distribution. The dominant frequency of pressure pulsation in the impeller is the shaft frequency (fn), and the secondary frequency of 0.11 fn is the characteristic frequency of stall vortex. As the stall degree increases, the amplitude of pressure pulsation increases. Turbulent dissipation entropy production and wall entropy production are identified as the primary contribution to energy loss. The majority of energy loss in the centrifugal pump occurs within the impeller and volute, and the entropy production increases proportionally to the stall degree. Wear rate is strongly correlated with the impact frequency, as the stall degree increases, both the impact frequency and wear rate exhibit a gradual decrease. [ABSTRACT FROM AUTHOR]

To improve the tribological performance of SS410 steel in seawater, TiCrN and CrSiN coatings were deposited using PVD sputtering and thoroughly analyzed. The CrSiN coating, which exhibits higher hardness and better corrosion resistance, achieved a protective efficiency of 83.70%, surpassing the TiCrN coating by 14% according to anodic polarization tests. Friction and wear properties were evaluated with a ball-on-disk tribometer in artificial seawater, following ASTM G77 standards. The CrSiN coating demonstrated lower friction coefficients and wear rates—1.362 × 10⁻⁶ mm3/N-m compared to 2.632 × 10⁻⁶ mm3/N-m for TiCrN at a 4N load—highlighting the positive impact of Si addition. These coatings markedly enhance the tribocorrosion resistance of AISI 410 steel, addressing issues in marine engine components, extending their service life, and ensuring reliable performance in severe marine conditions. SEM analysis of the uncoated SS410 surface revealed pits and deep grooves. [ABSTRACT FROM AUTHOR]

Pins and jacks play an important role in the transmission capability and reliability of electrical connectors. Their surface coating is especially vulnerable under mechanical friction or varying temperature condition. In this work, the repetitive mechanical insertion and withdrawal experiments are conducted with the use of self-designed test rig. The wear and corrosion behaviors of circular electrical connectors are experimentally investigated under mechanical operations at temperature ranging from 25 to 120 °C. The variations in contact resistance and force observed in the mechanical wear tests are recorded and interpreted explicitly. The effect of temperature on the insertion characteristic curve is compared and analyzed. Based on the variation in contact resistance and force, surface morphology and element analysis, the degradation mechanisms of connectors under different temperatures are illustrated explicitly. The mechanical lifetime of connectors is approximately 12,500, 15,000 and 8500 at 25, 60 and 120 °C, respectively. The results show the temperature stress has a substantial influence on the wear and corrosion behavior of electrical contact interface. [ABSTRACT FROM AUTHOR]

Chemical mechanical planarization (CMP) of metal components is an essential step in the fabrication of integrated circuits. Metal CMP is a complex process where strategically activated (electro)chemical reactions serve to structurally weaken the surface layers of the material being processed, and the resulting overburdens are removed under low-force abrasion. Understanding the tribo-electrochemical mechanisms of this process is crucial to successfully designing the consumable materials for advanced CMP slurries that are needed for the new technology nodes. Using a model CMP system involving copper (wiring material in interconnect structures) and molybdenum (a new diffusion barrier material for copper), the present work illustrates a tribo-electroanalytical scheme for studying various mechanistic details of metal CMP. Electroanalytical probes are employed both in the absence and in the presence of surface polishing to quantify the interplay between mechanical abrasion and chemical surface modification. Weakly alkaline slurry formulations are tested with variable concentrations of silica abrasives and a complexing agent, citric acid. The results serve to examine the link between material removal and tribo-corrosion and to identify the functions of the active slurry additives in governing the rates and selectivity of material removal for CMP. [ABSTRACT FROM AUTHOR]

The present work is focused on the manufacturing of a special self‐developed tribocorrosion setup with a controlled incubated environment. The comparative studies between wrought Co27Cr6Mo and Ti6Al7Nb alloys are performed with the respective tribometer in Ringer's solution at 37 °C. It is found that the CoCrMo alloy demonstrated a noble open circuit potential not only in non‐wear condition but also under wear conditions, in comparison to Ti6Al7Nb. The mass loss rate examined at open circuit potential and at a constant potential of 0.2 V versus Ag|AgCl|3.5 m KCl also suggests a similar superiority of the CoCrMo alloy. [ABSTRACT FROM AUTHOR]

In this work, a comparative study of the tribological performance of two hard coatings, CrN/TiBN, was conducted for research purposes and industrial applications in food products, particularly for food packaging into cans using the double hermetic sealing process. CrN and TiBN coatings were successfully deposited on a base-cobalt metal substrate of a CoCrW commercial alloy using physical vapor deposition by arc evaporation (AEPVD) technology to improve the tribological properties of the commercial alloy, including wear and corrosion resistance, lower coefficient of friction, and overall durability. This research focuses on conducting scratch and abrasion wear resistance tests in dry conditions; specifically, it pursues to evaluate the wear corrosion properties, known as tribocorrosion performance, on CrN/TiBN hard coatings. The experimental results show that the CrN coating (2.9 μm) is slightly thicker than the TiBN coating (2.7 μm), with a 47 N critical load. It also shows a lower coefficient of friction (CoF) in a dry environment, while the TiBN coating showed total detachment and a high coefficient of friction in a dry environment condition. Tribocorrosion testing in brine aqueous solution indicated that CrN coating shows a high friction coefficient with a higher open circuit potential value (Ecorr), and TiBN shows the lowest corrosion potential (Ecorr) and the lowest friction coefficient. This suggests that CrN could provide better corrosion protection for commercial cobalt alloys and improve tool performance during the food canning process in brine environments. [ABSTRACT FROM AUTHOR]

The corrosion–wear coupling damage failure of 8Cr4Mo4V bearing steel under marine atmospheric conditions significantly limits aeroengine bearing applications. The present work aims to investigate the evolution of the corrosion–wear properties of 8Cr4Mo4V bearing steel at varied corrosion intervals and estimate the corrosion–wear interaction (CWI) effect. Neutral salt spray tests combined with tribological experiments were employed to explore the effect of corrosion on wear and the influence of wear on corrosion, and a quantitative characterization method of corrosion–wear interactions was proposed by establishing the component relationships of material losses in the corrosion–wear process. The results indicate that the corrosion rates initially increase and then decrease, ultimately resulting in a pattern characterized by predominant total corrosion and nested localized corrosion. The corroded surfaces tremendously influence the friction coefficient curves at the third stage, and a synergistic acceleration effect exists in the CWI behavior of 8Cr4Mo4V bearing steel under the action of corrosion and wear. A sample corroded for 6 h displayed the significant facilitative effect of corrosion on wear, exhibiting the highest CWI ratio and a greater total mass loss primarily attributed to corrosion. This study offers a significant reference for the quantitative assessment of the tribo-corrosion properties of bearings in a marine atmospheric environment. [ABSTRACT FROM AUTHOR]

During the operation of the waste liquid incinerator, the alkali metal slag might adhere to the surface of the refractory material to form an inhomogeneous solid slag layer, causing the furnace lining to be simultaneously corroded by three phases of alkali metals: vapor, molten salt, and slag. This phenomenon intensifies the damage to the refractory material. Therefore, this paper investigates the mass transfer and permeation process, phase change process and corrosion rate of Na 2 CO 3 inside corundum refractory materials in three phases: Na vapor, molten Na 2 CO 3 and Na-slag. The results showed that alkali vapor penetrated the interior through the pores, and the NaAlO 2 and β-Al 2 O 3 generated by the reaction led to the volume expansion and microcracks. Na vapor continued to penetrate the interior along the cracks and eroded the sample, and the higher the temperature the greater Na vapor penetration. In vapor phase corrosion, the effect of corrosion time on the erosion resistance of corundum refractories is less than that of temperature, and the increase in corrosion time does not lead to the formation of additional new phases. In the molten salt corrosion experiments, it was found that the molten salt corrosion was accompanied by vapor phase corrosion at 1100 °C, and the amount of Na 2 CO 3 has a greater effect on the corroded mass than the temperature. Comparing the corrosion of refractory materials by the three phases of Na 2 CO 3 , the molten salt corrosion rate was the highest, followed by the vapor phase corrosion, and finally the slag corrosion. It is concluded that the slag layer can effectively prevent the corrosion of the refractory material by alkali metal molten salts and vapors, thus prolonging the service life of refractories. [ABSTRACT FROM AUTHOR]

Directly crystallizing strontium titanate (SrTiO 3) nanoparticles from a solution near room temperature poses a challenge due to Ti ions easily form colloids and result in amorphous products. It is also difficult to ensure the uniform incorporation of the dopants into the lattice during synthesis of doped samples. This study successfully achieved this task using the direct synthesis from solution (DSS) method. Both undoped SrTiO 3 nanoparticles and Fe-doped one were synthesized in an ethanol solution at the temperatures ranging from 60 to 80 °C, resulting in homogeneous grains with an average size of approximately 15 nm. Despite the solubility limit of Fe3+ in bulk SrTiO 3 being around 2.5 %, we successfully synthesized Fe-doped SrTiO 3 nanocrystals with high doping level even at a dose of 10 %. The tribocatalytic performance of both undoped and Fe-doped SrTiO 3 nanoparticles was evaluated for methylene blue degradation in a solution. Undoped SrTiO 3 nanoparticles showed similar catalytic performance to P25. In contrast, Fe-doped SrTiO 3 nanoparticles exhibited much higher catalytic performance. This enhanced catalytic performance is attributed to the presence of oxygen vacancies, which are introduced by doping Fe3+ into the SrTiO 3 lattice to substitute the Ti ion. [ABSTRACT FROM AUTHOR]

Crevice corrosion in modular taper junctions of hip or knee replacements using cobalt-chrome-molybdenum (CoCrMo) alloys remains a clinical concern. Non-mechanically-driven corrosion has been less explored compared to mechanically assisted crevice corrosion. This study hypothesized that solution chemistry within crevices, inflammation, and cathodic electrode potential shifts during fretting result in low pH and generate reactive oxygen species (ROS), affecting oxide film behavior. This study investigated how resistance and capacitance of the CoCrMo oxide film (i.e., corrosion resistance) are modified in simulated in vivo crevice environments of modular taper junctions. Six solutions were evaluated (two pH levels: 1 and 7.4 and four hydrogen peroxide (H 2 O 2) concentrations: 0, 0.001, 0.01 and 0.1 M). R p versus voltage and Mott–Schottky plots were created from symmetry-based electrochemical impedance spectroscopy (sbEIS). At pH 1, the semiconductor transition to p-type occurs at more anodic potentials and higher flat band potentials were found. H 2 O 2 decreased the flat band potential and slope in the Mott–Schottky plot. Higher H 2 O 2 in pH 7.4 solution significantly modified the oxide film, leading to increased donor density (p = 0.0004) and a 150-fold reduction in R p in the cathodic potential range at -1 V (p = 0.0005). The most unfavorable condition (0.1 M H 2 O 2 pH 1) resulted in a 250-fold lower resistance compared to phosphate buffered saline (PBS) pH 7.4 at -1 V (p = 0.0013). This study highlights the corrosion susceptibility of CoCrMo under adverse chemical and potential conditions, identifying increased defects in the oxide film due to ROS, hydrogen ions and electrode potential. Corrosion of cobalt chrome molybdenum alloy caused by direct chemical attack in the crevice region of hip replacements, such as modular taper junctions, remains a clinical concern. The junction environment contains adverse chemical compositions, including high acidity and reactive oxygen species (ROS) due to inflammatory responses against the corrosion products. We simulate inflammatory environments with different pH levels and hydrogen peroxide, representative of ROS. We employ electrochemical impedance spectroscopy and apply stepwise voltage over the range induced by tribocorrosion processes. We relate the effect of adverse chemical components on corrosion and semiconducting behavior of the oxide film using Mott–Schottky analysis. This study shows how pH and ROS concentration compromises the oxide film potentially leading to non-mechanically induced corrosion. [Display omitted] [ABSTRACT FROM AUTHOR]

Titanium alloys are encouraging materials as bone implantations in medical operations due to their interesting performances. However, wear debris engendered by wear was found to be the biggest handicap in terms of implant longevity. On the other hand, the biological environment has been considered to impact the tribological response. In this context, this work investigated the effect of the lubrication on the tribological response of the TiAl6V4/TiAl6V4 couple using a pin-on-disk tribometer. Thus, four various bio-lubricants were used: the physiological solution (NaCl 0.9%), nigella and sesame natural oils and Hyalgan® (sodium hyaluronate) used for the treatment of osteoarthritis (OA). The results displayed an enhancement in the friction and wear behaviors of the TiAl6V4/TiAl6V4 pair in the presence of natural oils. The analyses of the chemical structure of natural oils in terms of the unsaturations number (UN) suggest the existence of a dependency between the oil chemical structure and the wear resistance. The wear mechanism of the titanium alloys is governed by the continuous wear process of the formed and re-formed thin oxide layer on the metallic surface. It is found that the change of wear mechanism with the use of oils is mainly linked to their structure. In fact, natural oils have the ability to generate a dense lubricating layer on the metallic surface which will reduce wear. [ABSTRACT FROM AUTHOR]

A stochastic uncertain tribodynamic model is established for a spur gear pair for the first time. The stochastic uncertainty of pinion rotation speed propagated to lubrication performance is investigated. The probability density function of the minimum lubricant film thickness hmin evolves over time periodically at interval of an engagement process. Correspondence between abrupt increase in meshing force and amplification of hmin uncertainty is found. Robust and reliable lubrication performance can be achieved by suppressing the hmin uncertainty and decreasing the lubrication failure probability. This can be done by increasing lubricant viscosity, and decreasing input torque and uncertainty level of input rotation speed. This work lays a solid foundation for robust and reliability based optimization for tribodynamic gear system. [ABSTRACT FROM AUTHOR]

The dry wear and tribocorrosion behavior of the Mg-Zn-Gd-Zr alloy after extrusion and heat treatment with the quench control method at different loads have been investigated. The results showed that, after heat treatment, the wear resistance of the alloy increased significantly compared to the extruded alloy. The wear rate in the corrosive environment was lower than dry wear at low loads but increased with increasing load. It was found that, in dry wear, with increasing load, the dominant wear mechanism has changed from abrasion to oxidation, and, in tribocorrosion, the presence of a homogeneous I phase in the alloy has increased the corrosion and wear resistance. [ABSTRACT FROM AUTHOR]

This study explores the impact of additive manufactured porous architecture on the tribological performance of Ti6Al4V. Biomimetic porous architectures were manufactured on dense multi-layer using direct energy deposition with a dense layer followed by a porous layer. Varied scanning intervals during laser processing for the porous layer influenced the microstructure and, consequently, the hardness, the corrosion resistance and the tribological behavior of the dense layer. The results indicate a substantial improvement in tribocorrosion performance, particularly noteworthy in reducing corrosive wear rates, making porous architectures beneficial for both biomimetic structures and enhanced tribocorrosion resistance in body fluids. [ABSTRACT FROM AUTHOR]

The relationship between microstructure and erosion-corrosion behavior in 28 wt pct Cr irons with (1 to 6) wt pct Mo and (1 to 4) wt pct W addition was investigated. As-cast irons were destabilized at 1000 °C for 4 hours, and then air-cooled. Microstructural investigation and phase identification were performed by optical microscopy, scanning electron microscopy, X-ray diffraction, and transmission electron microscopy. Vickers macro- and micro-hardness, potentiodynamic testing and erosion–corrosion behavior were investigated. The irons with 1 and 6 wt pct Mo promoted the formation of M6C and M23C6, while the irons with 1 and 4 wt pct W caused the chemical composition to be hypereutectic promoting the formation of primary M7C3 and eutectic M6C. After destabilization, the transformation of austenite to secondary carbides and martensite was observed in all the irons, with Mo or W addition promoting finer secondary carbides. During destabilization, the eutectic M7C3 carbides changed from M7C3 to a duplex M7C3–M23C6, core–shell structure. Vickers macro-hardness and micro-hardness in the as-cast and after-destabilization conditions were increased with increasing Mo or W addition. Secondary passivation was found in the iron with 6 wt pct Mo, suggesting secondary passive film formation. The as-cast iron with 6 wt pct Mo and the destabilized iron with 4 wt pct W exhibited the highest erosion–corrosion resistance. [ABSTRACT FROM AUTHOR]

This paper reports the thermally activated ultralow friction of 100% cellulose nanofiber (CNF) molding. The mechanism of friction reduction was investigated using a laboratory-built in-situ Raman tribometer. Our experimental results showed that a CNF molding exhibited an ultralow friction coefficient of below 0.04 in a CNF ring and steel disk tribopair under high-temperature conditions (T > 100°C). The results of the temperature-rise friction test showed that the friction coefficient of the CNF molding strongly depended on the temperature and decreased linearly with increasing temperature. The in situ tribo-Raman monitoring results, during friction, indicated a change in the structure of the CNF molding. Therefore, the crystallinity indices and lengths of the CNF fibers gradually changed as the temperature increased. Moreover, transfer tribofilms were observed on the counter-steel surface against the CNF rings. When the CNF molding exhibited thermally activated ultralow friction, the tribofilm was mainly composed of cellulose and graphitic carbon. Our results suggest that the thermal and friction-activated structural transformations of CNF molding and CNFderived transfer film formation are pivotal factors contributing to the ultralow friction phenomenon observed in CNF molding at high temperatures. [ABSTRACT FROM AUTHOR]

The ZrN coatings were prepared using multi-arc ion plating (MAIP) under different N 2 partial pressures ranging from 10 % to 80 %. A comprehensive analysis of the microstructure, electrochemical behavior, and tribocorrosion properties of these coatings showed a gradual deposition rate decrease with rising N 2 partial pressure. Analysis using GIXRD revealed higher N 2 pressure led to a shift in crystal orientation from (111) to (200), initially increasing corrosion resistance but later declining. At 70 % N 2 pressure, the ZrN coating exhibited the lowest values of capacitance C po (8.89 μF cm−2) and double-layer capacitance C dl (1.14 × 10−7 F cm−2), with the highest values for the two-time constants τ recorded as 0.274 s and 5.749 s. The tribocorrosion behavior correlated closely with the corrosion performance, with the ZrN-70 % coating demonstrating superior tribocorrosion resistance and a minimal wear rate of 4.25 × 10−5 mm3/Nm. While the ZrN-80 % coating exhibited the lowest wear rate of 2.67 × 10−5 mm3/Nm, but was more susceptible to friction and corrosion synergy, causing localized failure. The outcomes reveal crystal texture significantly affected on the electrochemical and tribocorrosion characteristics of the coatings, primarily attributed to the robust passivation tendency and stability of the passivation film associated with the (200) crystal orientation. The dominant wear mechanism identified involves the interplay of adhesive, abrasive, and corrosion-erosion wear processes. Based on these results, ZrN coatings prepared using MAIP are expected to emerge as candidate materials for critical friction components in marine equipment or other corrosion-erosion environments. [ABSTRACT FROM AUTHOR]

Implants must be able to support masticatory loads combined with a high biocompatibility and wear resistance in the presence of a corrosive environment. In order to improve the simultaneous wear and corrosion response at the implant abutment interface, PEEK/titanium and titanium/titanium implants were assessed by tribocorrosion analyses under conditions mimicking the oral environment. The tribocorrosion tests samples were performed on a reciprocating ball-onplate tribometer at 30N normal load in artificial saliva at 370C. Open circuit potential (OCP) was measured before and after reciprocating sliding tests. The worn surfaces were characterized by stereomicroscopy. The results revealed a lower wear rate on PEEK combined with a lower coefficient of friction (COF), when compared to titanium. [ABSTRACT FROM AUTHOR]

To satisfy the service requirements of wave-absorbing materials in harsh environments, it is important to design and manufacture corrosion-resistant composite-absorbing materials. According to the strategy of impedance matching and the dissipation behaviour of nickel-based alloys, AlN ceramics, and MAX-phase Ti 3 SiC 2 multicomponent composite-regulated materials were studied. As an additive manufacturing technology, multilevel heterointerface composites with core–shell structures were obtained by laser cladding. The construction of a unique core–shell structure of a metal–ceramic and ceramic (core)–ceramic (shell) multi-level heterogeneous interface increased the interfacial relaxation and multiple dissipation and improved the impedance matching. The results enabled the N20M3 cladding coating to exhibit excellent microwave absorption characteristics, with a reflection loss of −32.84 dB at the ultra-thin thickness of 1.8 mm. Additionally, the composites exhibited excellent corrosion resistance, high hardness, and relatively good resistance to erosion wear. This work promotes the durability of wave-absorbing materials under severe conditions, as well as the integration of the efficient manufacturing of wave-absorbing materials. [ABSTRACT FROM AUTHOR]