Heavy-duty Conditions Research Articles

Weak Feature Extraction Method for Bearing Faults Under Low-Speed Heavy-Duty Conditions

Weak Feature Extraction Method for Bearing Faults Under Low-Speed Heavy-Duty Conditions

Clarifying the Limitations of Copper Hexacyanoferrate in Rechargeable Aqueous Zinc-Ion Batteries Via in Situ X-Ray Techniques

Copper hexacyanoferrate (CuHCF) is a compound belonging to the Prussian Blue Analogue (PBA) family, known for its open structure with cubic symmetry and large cavities capable of accommodating various cations, such as alkali-metal ions and divalent cations, making it an interesting candidate for ion-insertion batteries.CuHCF has been increasingly attracting attention for innovative approaches in rechargeable aqueous batteries which represent an emerging alternative technology for realizing sustainable and efficient stationary storage of intermittent electricity produced via renewable sources1.CuHCF stands out as an environmentally friendly cathode material in rechargeable aqueous Zn-ion batteries (ZIBs), enabling the realization of cost-effective and safe cells that support elevated charge/discharge rates and thus provide high power delivery2, 3. Relying only on abundant, inexpensive and non-toxic materials, combined with non-flammable and mildly acidic electrolytes, Zn/CuHCF cells are an attractive electrochemical system for addressing the challenges of developing energy storage devices for power grids due to their quick response and contained fabrication costs, although their energy density is intrinsically limited4 (< 100 Wh·kg-1).CuHCF displays one of the highest operating potentials (≈1.7 V vs. Zn2+/Zn) among cathode materials in aqueous ZIBs2, 3 and a modest capacity of ≈60 mAhg-1. Yet, what sets CuHCF apart is its ability to undergo ion insertion/de-insertion with negligible structural variations or volume changes5, making these electrodes apt for extensive cycling under heavy-duty conditions without risking induced mechanical or electrical damages causing early cell failure.However, a series of obstacles are present along the way of Zn/CuHCF cell development. Aside from issues on the Zinc side (e.g. uncontrolled Zn deposition/stripping), notoriously challenging in terms of interface stabilization6 and effective utilization4, significant limitations arise from the CuHCF ageing mechanisms during cycling. Such mechanisms have remained elusive so far, mostly due to the complexity of this compound and a simultaneous interaction of various species in the electrochemical processes. To date, there have been only speculative attempts to explain the capacity fading in CuHCF and, consequently, only a few scenarios have been suggested for it. Possible phase segregation and formation of spurious, non-stoichiometric Zn-rich phases (e.g. ZnxCu1-xHCF) have been argued7-9, while also signs of Cu dissolution were previously detected10, yet thought to be minimal and not affecting the CuHCF performances.Here, we will shed light on the limitations of CuHCF during cycling in ZIBs and explore its ageing mechanism by conducting a thorough study employing X-ray techniques11. Our investigation reveals that CuHCF is less stable than previously assumed, and that its debated Cu dissolution is linked to the ageing process11, forming Cu vacancies that can accept Zn2+. This Cu dissolution also results in a gradual activation of the Fe3+/Fe2+ couple, which has unambiguously been assigned to the appearance of a plateau on charge at ≈1.8 V vs. Zn2+/Zn (Figure 1). This is believed as the main contributor to the subsequent capacity loss. These insights into the CuHCF ageing in ZIBs may help in devising strategies to mitigate this critical aspect and improve battery performances in terms of stability and cycle life. Figure 1. (a) Scheme of an aqueous Zn/CuHCF cell. (b) Galvanostatic charge-discharge profiles of a Zn/CuHCF cell between 1.00 and 2.15 V at 0.6 mAcm-2. Note the emergence of a sloping plateau around 1.8 V and a slight capacity loss after 200 cycles. Acknowledgements M.V. acknowledges the funding by the ÅForsk Foundation, the support by the Swedish Electromobility Centre, the Swedish Energy Agency and StandUp for Energy. References C. D. Wessells, R. A. Huggins and Y. Cui, Nature communications, 2011, 2, 1-5.R. Trócoli and F. La Mantia, ChemSusChem, 2015, 8, 481-485. Z. Jia, B. Wang and Y. Wang, Materials Chemistry and Physics, 2015, 149, 601-606.G. Zampardi and F. La Mantia, Nature communications, 2022, 13, 687. V. Renman, D. O. Ojwang, M. Valvo, C. P. Gómez, T. Gustafsson and G. Svensson, Journal of Power Sources, 2017, 369, 146-153. Z. Cao, P. Zhuang, X. Zhang, M. Ye, J. Shen and P. M. Ajayan, Advanced Energy Materials, 2020, 10, 2001599.G. Kasiri, R. Trócoli, A. B. Hashemi and F. La Mantia, Electrochimica Acta, 2016, 222, 74-83. R. Trócoli, G. Kasiri and F. La Mantia, Journal of Power Sources, 2018, 400, 167-171. G. Kasiri, J. Glenneberg, A. B. Hashemi, R. Kun and F. La Mantia, Energy Storage Materials, 2019, 19, 360-369. J. Lim, G. Kasiri, R. Sahu, K. Schweinar, K. Hengge, D. Raabe, F. La Mantia and C. Scheu, Chemistry–A European Journal, 2020, 26, 4917-4922. M. Görlin, D. O. Ojwang, M.-T. Lee, V. Renman, C.-W. Tai and M. Valvo, ACS Applied Materials & Interfaces, 2021, 13, 59962-59974. Figure 1

Large eddy simulation of OME3 and OME4 spray combustion under heavy-duty conditions

The synthetic diesel fuel (Poly-)oxymethylene ether (OME) has various interesting properties for the transport sector. OME reduces emissions in direct injection (DI) diesel engines, e.g., soot and NOx, and is considered CO2 neutral. While most studies have examined a mixture of OMEs with different chain lengths, recent studies have focused on neat OME3 and OME4. In the literature similar chemical ignition delay times were shown under homogeneous conditions and significant differences were reported in their thermophysical properties. Furthermore, differences between OME3 and OME4 in terms of the mixture formation were shown on a heavy-duty injector under non-reactive conditions. The question of how this mixture formation affects the ignition and flame characteristics of neat OME3 and OME4 spray flames remains unresolved. To address this topic, this study conducts a combined experimental and numerical investigation under inert and reactive spray conditions for OME3 and OME4 on a heavy-duty injector. Large Eddy Simulations (LESs) and high-pressure, high-temperature spray chamber measurements are conducted. The distinct differences between neat OME3 and OME4 are analyzed along the cause–effect chain comprising the mixture formation, ignition behavior and its effects on the overall heat release rate. Based on the differences in the thermophysical properties, e.g., density and vapor pressure, the investigations in inert conditions reveal differences in the liquid penetration and mixture formation. The reactive spray flame measurements and simulations show a significant offset in the ignition delay time for OME3 and OME4. An explanation is found in the significantly different distribution of the scalar dissipation rate due to the differences in the mixture formation. Despite the differing ignition delay times, similar local flame structures are found for both fuels.

Feasibility of developing green water batteries based on poly-lactic acid and polybutylene succinate: A computational study on groasis waterboxx technology

Developing water-saving technologies such as Groasis Waterboxx (GW) based on environmentally friendly materials is a robust strategy to undermine the destructive effects of the agricultural industry on nature and society. Here, we simulated the injection molding process of green GWs made of poly-lactic acid (PLA) and polybutylene succinate (PBS) and analyzed the performance of the parts in heavy-duty conditions. The effects of different process parameters on cycle time, consumed energy, and final product qualities, including mechanical and visual aspects, were investigated by Autodesk Moldflow to compare biopolymers with polypropylene (PP). GW performance in the Sahara Desert was simulated with the help of Abaqus. The simulations results revealed that PLA exhibited shorter injection and cooling times compared to PP, with reduction of 44% and 56%, respectively, thus indicating faster production speed. However, PBS-based part demonstrated mechanical qualities similar to PP. PLA shows lower shrinkage and warpage than PP despite that environmental simulations illustrated that PLA is impractical for use in areas with high thermal stresses because of overlapping the glass transition and ground temperature, leading to failure near land surface regions. The results are in qualitative agreement with experimental results reported by the manufacturer. Despite its biodegradability, PBS could provide a high safety factor of about 82% of PP samples. Although the injection of PBS consumed more energy than PP because of the higher required injection pressure, replacing PP with PBS is justified considering its high efficiency and eco-friendliness.

Fatigue life of unified riveted superstructures designed by Transmostproject with the introduction of increased axle loads

The article presents a study of the residual fatigue life of superstructures during the introduction of trains with increased axial loads on bridges with riveted superstructures, designed in the fifties of the last century. Unified metal superstructures have been in relatively heavy duty conditions for more than 60 years. During lcontinuous operation, processes occur in elements and joints that lead to the appearance and development of various damages and varying degree failures of hazard, so it is necessary to decide on the further operation of old bridge spans and their replacement. When determining the fatigue life, the linear addition hypothesis of fatigue damage accumulation was used, taking into account the increase in stresses with the introduction of increased axial loads. As a critical measure of damage, providing a given reliability, the value obtained from the calculation results of several hundred cracks in riveted superstructures of older design standards was adopted. The increase in load from the installation of a ballastless bridge floor is taken into account. To determine the residual fatigue life, fatigue data is used depending on the concentration of stresses magnitude in the attachments of the main truss elements. For a more accurate determination of the rivet joints operation stage, the author carried out a wear-out calculation through operation period. The introduction of heavier train loads will lead to an increase in the accumulation of fatigue damage in the elements. If weak rivets in attachments are found during inspection, they must be replaced with high-strength bolts to increase fatigue life. The author obtained that the residual fatigue life of the span structures designed by Transmostproekt has not yet been fully exhausted even with the introduction of heavy trains with a wagon axle load of 27–30 tons.

Experimental and numerical study on the mixed lubrication performances of a new bearing

The traditional water-lubricated bearings are difficult to form effective lubricating film under extreme low-speed and heavy-duty conditions, resulting in the low-load, high-resistance, high-vibration and high-noise shortcomings. The deep-physical mechanisms are not clear. The paper investigates the mixed lubrication performances and critical characteristics for water-lubricated bearings under extreme conditions. A novel multi-field coupling lubrication model is proposed. The functional mapping relationships among lubrication performances, the critical characteristics and the influencing factors are developed. The rotor dynamic models considering surface micro-topography are built. The variation mechanisms of the dynamic behaviors are revealed. The theoretical analysis is consistent with experiment, which proves the model and algorithm’s correctness. The academic value of the paper is expected to achieve a novel breakthrough in formation of effective hydrodynamic film under extreme severe conditions for such bearings.

Analysis of the thermal stability of residual stresses induced in Ti-6Al-4 V by high density LSP treatments

Laser Shock Processing (LSP) is increasingly applied as an effective technology for the improvement mechanical and surface properties of metallic materials for different types of components, mostly as a means of enhancement of their fatigue life behavior. As reported in previous contributions, a main effect resulting from the application of the LSP technique consists in the generation of relatively deep compression residual stresses fields allowing an improved mechanical behavior. In this paper, the special case of Ti-6Al-4 V alloy is considered with specific consideration of the microstructural changes and residual stresses fields justifying those macroscopic effects. In particular, the effect of the application of different typical LSP intensities on the microstructure and residual stresses fields introduced in this material and their possible correlation to the associated surface effects are analyzed. Emphasis is placed on the study of the thermal stability of these fields after an aging heat treatment at typical high temperature working conditions. The results show that, according to expectations, a certain level of residual stresses and dislocation density remains after in-work thermal aging. The combination of different material characterization techniques has made possible to obtain a correlated set of results highlighting the complementarity of different scale approaches from surface (X-ray) to bulk (neutrons) methods. A model based on the evolution of immobile dislocation density is proposed to rationalize the distribution of dislocation densities, pointing out that plastic deformation is retained. The results clearly show such material improvement stability under typical heavy-duty conditions, thus endorsing the use of the LSP for Ti-6Al-4 V as a suitable technology for industrial applications in relatively high temperature conditions.

Analysis method of carrying capacity accuracy of three-row roller slewing bearing

Three-row roller slewing bearings are one of the critical core components of large rotating equipment. Heavy-duty conditions have extremely high requirements for the carrying capacity. The new load capacity analysis method proposed in this paper can effectively improve the accuracy and efficiency of the carrying capacity analysis of three-row roller slewing bearings. The three-row roller slewing bearing solid rollers are replaced in the model by the upper and lower halves of the rollers and two springs. The local contact model of the three-row roller slewing bearing was established and verified by the Hertz contact theory. The overall finite element model of the three-row roller slewing bearing was verified by strain tests. The new method can calculate the stress and strain distribution, load distribution, and deformation of the entire circle of the three-row roller slewing bearing and reduce the mesh number of the finite element of the overall model. Roller chamfer can also be considered closer to the actual working conditions and improves calculation efficiency and accuracy.

Justification of geometrical parameters of lining plates for a belt conveyor drive drum

Belt conveyors are widely used in mining industry in open-pit and underground mining for moving bulkload in horizontal and inclined directions to the sites of processing. In order to create the best conditions of frictional contact between a belt and a drum, various methods of drive drum lining are used. The main lining material is rubber of different grades, providing proper coefficient of friction of a belt with a drum (within the range of 0.6–0.62). A drive drum lining material must have high wear resistance, thermal resistance, mechanical strength, ability not to accumulate electric charges on the surface and not to generate dangerous concentrations of toxic components (for example, chlorine gases, carbon monoxide) when heated. The use of ceramic lining opens up great opportunities for increasing lining durability and useful life of high capacity heavy-duty conveyors. The paper presents the results of the study of stress-strain state of belt conveyor drive drum ceramic lining plates. We used Solid Work Simulation environment in the study on the basis of the accepted analytical model of plate-belt contact for drive drum with diameter D = 1250 mm, belt width L = 1000 mm, and the belt entering branch tension value Se = 25400 daN with regard to the value, direction, and nature of the acting loads. On the basis of stress-strain analysis of alumina ceramics lining plates, the favorable geometrical parameters of the plate cleats (projections) and the required properties of lining material ensuring the proper load-carrying capacity at the contact with the belt rubber facing were found. It was established that a plate cleat diameter for heavy duty conditions should be not less than 4.5 mm and its end round R should be within the limits of 0.5–0.6 mm, and, in the base, 0.3–0.4 mm at a cleat height of 1.0–1.4 mm in order to prevent stress concentration in hazardous sections. It was also established that alumina ceramics bending strength must be no less than 350 MPa for effective functioning of rubber-ceramic lining. Simulation of a plate stress-strain state on exposure to alternating loads made it possible to identify characteristic areas with maximum stress concentration, which were foci of crack nucleation. Thus, it became possible to predict lining useful life.

Dynamic modeling and analysis of elastic isolation damping gears

Transmission error is the main excitation source of gear vibration and noise, how to reduce the transmission error has always been the focus of the research on gear dynamics. In this study, a new type of cylindrical spur gear with elastic isolation is developed for the reduction of transmission error. The elastic isolation damping gear includes three parts: the gear body, the elastic isolation layer, and the involute profile body. Dynamic models are established with the elastic isolation damping gear using lumped parameter method. Dynamic characteristics are simulated via spur gear pair examples by the Runge-Kutta algorithm. By comparing the simulation results of three gear models, the dynamic response of the elastic isolation damping gear with sliding friction is illustrated. The influence of different parameters of the elastic isolation layer on the dynamic response for the elastic isolation damping gear model is carried out. The results indicate that the proposed elastic isolation damping gear model is effective in reducing dynamic transmission error, especially for torque fluctuation, high-speed and heavy-duty conditions. Parameter influence analysis guides the design of elastic isolation damping gears with low transmission error.

Driving mode analysis of quarter-elliptical flaw under cyclic loading

The operations of large moving systems are often compromised under high-speed and heavy duty conditions owing to the fatigue deterioration caused by surface flaws. In this context, the present research examines a novel computational model to explore the stability of stress raisers such as quarter-elliptical cracks and semi-elliptical cracks. The influences of crack-tip interactions and stress ratio effects on driving mode progression are analyzed through a damage tolerance-based analytical strategy.

Characterizations of Polymer Gears Fabricated by Differential Pressure Vacuum Casting and Fused Deposition Modeling.

In recent years, polymer gears have gradually become more widely employed in medium or heavy-duty conditions based on weight reduction in transmission systems because of low costs and low noise compared to metal gears. In the current industry, proposing a cost-effective approach to the manufacture of polymer gears is an important research issue. This paper investigates the wear performance of polymer gears fabricated with eight different kinds of materials using differential pressure vacuum casting and additive manufacturing techniques. It was found that both additive manufacturing and differential pressure vacuum casting seem to be an effective and cost-effective method for low-volume production of polymer gears for industrial applications. The gate number of one is the optimal design to manufacture a silicone rubber mold for differential pressure vacuum casting since the weld line of the polymer is only one. Polyurethane resin, 10 wt.% glass fiber-reinforced polylatic acid (PLA), or 10 wt.% carbon fiber-reinforced PLA are suggested for manufacturing gears for small quantity demand based on the deformation and abrasion weight percentage under process conditions of 3000 rpm for 120 min; epoxy resin is not suitable for making gears because part of the teeth will be broken during abrasion testing.

The impact of using pure ethanol additives on gasoline fuel with respect to SI engine emissions

A major problem in the gasoline engine operation process under heavy-duty conditions is the knocking phenomenon, noises produced in the combustion chamber during the combustion procedure as a consequence of the pre-ignition process. These occur effect of the high temperature of the air, which causes fuel to ignite without additional activation energy (spark). The octane number for gasoline fuel measures the resistance of the fuel to such auto-ignition. Experimental work was done in this study to study the influence of adding pure ethanol to conventional Iraqi gasoline fuel at percentages varying from 10% to 90% in 10% increments by volume, with various fuel properties like density, octane number, viscosity, fuel vapour pressure, and flash point temperature, measured and compared. Ethanol additives were found to increase fuel density, flash point temperature, viscosity, and octane number while reducing fuel vapour pressure. The engine utilised in the trials was a single-cylinder, gasoline engine, naturally aspirated and air-cooled. The experimental outcomes for specific fuel consumption showed decreases of up to 29% at the 90% volumetric percentage of ethanol in conventional gasoline fuel, and emissions of engine NOX, CO, and HC decreased by 67. 7%, 69%, and 61%, respectively, However, CO2 emissions increased.

Evaluation of factors influencing road dust loadings in a Latin American urban center

ABSTRACT Vehicle non-exhaust emissions are a major component of particle matter, including the direct wear of tires, brakes, road, and the resuspension of deposited particles. It is suggested that resuspended PM (RPM) emissions can be at the same magnitude or even larger than combustion emissions in urban centers. Factors affecting RPM can be included in four categories: road characteristics, traffic condition, land use, and meteorology. In order to study and evaluate these influencing factors, road dust less than 10 micrometers (RD10) was collected in 41 sites across Bogotá. The sampling points had diverse characteristics. RD10 levels varied between 1.0 and 45.8 mg/m2 with an average of 8.9 ± 8.4 mg/m2. Lower RD10 values were observed when vegetation density was high, pavement condition good, driving speeds fast and construction activities absent. On the contrary, RD10 increased under heavy-duty traffic influence and dry conditions. Among dust mitigation measures, management of land-use variables could be as important as traffic control and road maintenance. Implications: This study documented for the first time in Latin America dust loadings less than 10 micrometers, information that can be used to estimate resuspended particle matter emissions in the region. The influence of meteorology, traffic characteristics, road condition, and land-use variables was analyzed and quantified. The management of land-use variables could be as important as traffic control and road maintenance for road dust mitigation. Further research interests are discussed.

Enhancement of heavy-duty friction and wear characteristics of cast-iron surface by electrolytic micro-textures filled with MoS2

Cylinder liners made of cast iron are widely used in heavy-duty diesel engines. With the continuous strengthening of heavy-duty conditions of diesel engine, surface modifying technologies of piston ring and cylinder liner are gaining more attention. Two types of modified surfaces were prepared using cast-iron cylinder liner. One was a micro-texture prepared by electrolytic machining technology and the other was a MoS2-filled micro-texture prepared by cathodic reduction of thiosulfate. Modified cast-iron cylinder liners matched with chromium-based ceramic composite coated (CKS) rings were compared using the piston ring reciprocating liner test rig. Friction coefficient and wear depth of MoS2-filled microtextured liner were 8.4% and 51.5% lower than those of the microtextured liner under the simulated conditions of 50 MPa, 200 r/min and 250 °C, respectively. XPS of the MoS2-filled micro-textured surface revealed that both zinc dialkyl dithiophosphates (ZDDP) in the lubricating oil and MoS2 in the micro-textures were involved in the formation of the tribofilm with a good synergistic interaction. Typical compositions of friction-reducing and wear-resistant tribofilm on the platform area between the MoS2-filled micro dimples contained some amount of the zinc compounds ZnO, the short chain polyphospahtes FePO4, the unoxidized molybdenum compounds MoS2 and the sulfides FeS.

Performance analysis and optimization of a rigid-flexible parallel manipulator

In order to meet the design requirements of friction stir welding equipment, a three-degree-of-freedom rigid-flexible 3UPS-UP-3Cable-Driven (3UPS-UP-3CD) parallel manipulator was applied to the main feed mechanism of the friction stir welding robot. The kinematics analysis of the new parallel manipulator was carried out, and the complete homogeneous dimensional Jacobian matrix of the 3UPS-UP-3CD manipulator was solved. Through kinematic performance analysis, the carrying capacity, dexterity and stiffness of 3UPS-UP-3CD manipulator are obviously better than 3UPS-UP mechanism, and the impact of cables on the workspace can also be eliminated by adjusting the dimension parameter. The composite quality workspace map of the manipulator was drawn, and the composite kinematic performance index was proposed. Multiobjective optimization was completed for 3UPS-UP-3CD manipulator, and its performance was improved. The dynamic analysis of the manipulator was carried out, and the driving forces of two mechanisms were calculated under two trajectories. The results showed that the maximum driving force of 3UPS-UP-3CD manipulator was lower than 3UPS-UP mechanism, which proved that 3UPS-UP-3CD manipulator was more suitable for heavy-duty conditions.

Durable ultra‐low‐platinum ionomer‐free anode catalyst for hydrogen proton exchange membrane fuel cell

An ultra-low-platinum catalyst based on finely dispersed platinum (Pt) deposited on a highly porous complex microporous layer was investigated as a candidate of durable anode catalyst for hydrogen oxidation reaction (HOR) in proton exchange membrane fuel cells. Etching of teflonated and nitridized base carbon substrate in oxygen plasma and simultaneous deposition of cerium oxide were applied to increase active surface area and electrochemical activity of the platinum nanocatalyst. Ultra-low loadings of Pt (between 0.85 and 8.5 μg cm−2) deposited by magnetron sputtering on this substrate were assembled with Nafion 212 membrane and commercially available Pt/C cathodes (300-400 μg cm−2 Pt). Such membrane electrode assembly (MEA) with extremely low Pt content at anode can deliver high output power densities, reaching 0.95 W cm−2 or 0.65 W cm−2 with only 1.7 μg cm−2 of Pt, using H2 as fuel and pure O2 or air as an oxidant, respectively. Although electrocatalysts with highly dispersed active metals are known to often suffer from irreversible degradation, the above MEAs proved to be very stable when the cell was subjected to a durability test under heavy duty conditions of on/off cycling. The system with lower Pt content is more prone to water flooding which can, however, be eliminated by maintaining better control over the fuel humidity. Average decay of the cell voltage less than 50 μV h−1 was obtained in the cycling regime, while excellent stability <10 μV h−1 is achievable under the static load of 0.4 A cm−2.

Continuous damage-based Voronoi finite element analysis of contact fatigue of a wind turbine gear

Contact fatigue failures of gears, especially those used in heavy duty conditions such as wind turbine gears, become important issues in mechanical transmission industry. In the present work, a continuous damage mechanism and Voronoi-based finite element model is developed to investigate the contact fatigue of a wind turbine gear. Plane strain assumption is adopted to simplify the gear contact model. Voronoi tessellations are utilized to represent the microstructure topology of the gear material, and continuous damage mechanism is implemented to reflect the material degradation within critical substrate area. With the developed framework, the contact pressure distribution, intergranular mechanical response and the progressive fatigue damage at the grain boundaries during repeated gear meshing are evaluated and discussed in detail. The depths of the maximum shear stress reversal and the crack initiation agree well with previously reported findings. The influence of microstructure on the gear contact fatigue behavior is also investigated.

High protective performance coatings assembled by epoxy-modified furfural-acetone containing polyaniline nanowires for mild steel

High performance protective coatings applied under heavy duty condition will lengthen the structure’s service life, decrease maintenance times, economic and human life loss. Here, high protective performance coatings were prepared by dispersing polyaniline (PANI) nanowires into epoxy modified furfural-acetone (EMFA) resin matrix and then cured with phenalkamine. The protective performance of coatings was investigated by immersion experiments in 12% NaCl solution at 90 °C and Electrochemical Impedance Spectroscopy (EIS) measurements. The coating containing 1.0% PANI nanowires showed high impedance (>1010 ohm·cm2) after 80 days immersion, exhibiting great protective performance. X-ray photoelectron spectroscopy (XPS) surveys verified the formation of passive layer (Fe2O3/Fe3O4) on steel surface beneath the coating with 1.0% PANI. The bending test suggested that both the pure EMFA coating and the EMFA/PANI coating showed excellent flexibility of 2 mm. Here, measurement of water absorption, adhesion strength, pencil hardness and impact resistance were conducted to evaluate coatings performance.

Wear Behavior of CuSn Coated Piston Ring Sliding against Nodular Cast Iron Cylinder Liner under Heavy-Duty Conditions

In order to investigate the friction and wear behavior between the nodular cast iron cylinder liner (Fe) and CuSn coated piston ring under heavy-duty conditions, piston rings with chromium(Cr) coating and CuSn-Cr coating were tested using the piston ring reciprocating liner test rig at the simulated working conditions of 56 MPa, 200 r/min, 190 °C. Compared with the Cr/Fe pair, the CuSn coating consumption of the CuSn-Cr/Fe pair made friction coefficient and cylinder wear loss decrease by 2.8% and 51.5%, respectively. Different size Sn patches worn from the CuSn coated piston ring were embedded into the cylinder liner surface based on the surface topography. This process was shown to reduce the surface roughness of a cylinder liner and form flatter plateau structures. Chemical elements analysis indicated that plateau structures on the cylinder liner surface matched with CuSn-Cr coated ring are helpful to promote the tribo-chemical reaction and generate the reactive products to protect the mutually contacted asperities.