Friction Curves Research Articles

Effects of Y2O3 Content on Wear Resistance and Corrosion Resistance of 316L/TiC Coating Fabricated by Laser Cladding

Laser cladding technology is a surface modification technology emerging in recent years, and it is widely used in the marine engineering field. Since the structural steels used in marine engineering are mostly carbon steels, their wear resistance and corrosion resistance are poor. In this paper, 316 L stainless steel/TiC composite coatings with different Y2O3 addition amounts were fabricated on Q355B steel surface using the laser cladding technology, and the phase composition, microstructure, microhardness, wear resistance, and corrosion resistance of the coatings were investigated with an X-ray diffractometer (XRD), a scanning electron microscope (SEM), a digital microhardness tester, a friction and wear tester, and an electrochemical workstation. When Y2O3 is added, the crystals in the bottom part of the coating are basically broken and the organisation becomes more dense. When the Y2O3 addition amount is 2%, the hardness is highest, the frictional coefficient curve of the coating exhibits a stable descending trend, and the coating mass loss is the lowest. When Y2O3 is added at 1%, the dynamic potential polarisation curve shows high corrosion potential and low corrosion current density and exhibited the best performance in EIS. The added Y2O3 evidently improves the wear resistance and corrosion resistance of 316 L stainless steel/TiC composite coatings, and this provides a new possibility that a composite coating modified with rare earth oxide is used for repair of marine engineering structures.

Dizel Motorlarda Marş Motoru Seçimi

Starter selection is a critical decision in diesel engine design. The starter performance curves are generally accepted in the industry, with current on the horizontal axis and power, volts, speed and starter torque on the vertical axis. In this way, it is not possible to compare the starter performance curves with the engine friction force curve. In this study, a method has been developed for the selection of suitable starter for diesel engines. With the developed method, the starter performance curve is converted and the engine friction curve is shown on the same graph. With this method, it can be easily understood whether the starter is suitable for a diesel engine. In addition, possible problems that may be encountered during cold start-up can be foreseen. The developed method uses actual performance measurements given by the starter manufacturer. On the engine side, if there is an existing engine, engine friction test results are used. If the engine is in the design phase, the friction force results obtained by simulation are used.

Effect of annealing on the mechanical properties and cytocompatibility of CoCrMo alloy with tantalum coating

Cobalt–chromium–molybdenum (CoCrMo) alloy is frequently utilized to replace artificial joints and dental components. Tantalum (Ta) coating is used to improve the osteogenic property of CoCrMo alloy. Annealing treatment can increase the Ta coating adhesion and further improve wear resistance and biocompatibility. In this study, two kinds of thicknesses of Ta coatings were applied on CoCrMo alloy substrates via magnetron sputtering technology. The average thicknesses of the Ta coatings were 4.3 and 9.5 μm. The Ta coatings were annealed for 5 h at 800 °C, 900 °C, and 1000 °C, respectively. Results indicated that heat treatment improved the adhesion of the coatings. The Ta coatings were composed of stable body-centered cubic phase (α-Ta) and metastable tetragonal phase (β-Ta). The Ta coating with a thickness of 4.3 μm exhibited excellent wear resistance after being annealed at 800 °C, with little variability in the friction curve and a low average coefficient of friction. The adhesive force of the two coated samples increased initially and subsequently dropped as the annealing temperature increased. At 900 °C, the Ta-coated samples exhibited the highest adhesive force; after being annealed, the rate of cell proliferation increased. At 900 °C, samples with Ta coatings exhibited the highest rate of cell multiplication and the best cell compatibility compared with the other samples. Ta coatings' adhesive force, wear resistance, corrosion resistance, and cytocompatibility were all significantly enhanced at various annealing temperatures. Thus, the results of this work are a useful benchmark for the surface modification of metal implants used in medical procedures, and Ta coatings are a practical orthopedic material for the replacement of joints and bones.

Bioconvective nonlinear radiative flow of cross nanofluid due to porous oscillating surface with variable thermal conductivity and Cattaneo–Christov model

Present exploration elucidates the bio-convective time-dependent flow of Cross nanoparticles across periodically stretched surface immersed in porous space. Modified diffusion theories are employed to evaluate mass and thermic transference attributes effectively. Aspects of thermic transformation are additionally inspected with nonlinear radiation, variable thermic conductivity and heat generation characteristics. Magnetic consequences are deployed for physical importance. Dimensionless expressions are accomplished with pertinent transformations, and then analytically elucidated by homotopic technique. Physical importance of leading variables on curves of skin friction, temperature, microorganisms and concertation are premediated graphically. Numerical computations are executed to briefly notice the significance of relative variables on local Sherwood, motile density and Nusselt numbers and organized in respective tables. It is acknowledged that velocity curves display declining tendencies for enlarging buoyancy ratio, bio-convective Rayleigh and Weissenberg numbers. The present study accentuated that temperature boosted prominently for heat generation and variable thermic conductivity. The attained outcomes further divulge that concentration display diminishing results for solutal relaxation variable while such declining outcomes ensued in temperature for thermic relaxation variable. Furthermore, microorganism’s curves display declining responses for bio-convective Lewis and Peclet variables. Finally, shear wall force improved for magneto-porous variable but lessened for Weissenberg number.

Mechanism of Electrochemically Assisted Friction and Wear Behavior of GaN in KMnO4 Slurry

Electrochemically assisted friction and wear behavior of gallium nitride (GaN) in a KMnO4 slurry was investigated to optimize the composition of the chemical mechanical polishing (CMP) slurry, and the material removal effect of GaN was visually evaluated by using the coefficient of friction (COF) curve and wear area. The results showed that the surface oxidation of GaN was effectively enhanced by KMnO4 and electrochemical assistance. The average COF and wear area of GaN increased with stronger oxidation of the environmental media, which improved the removal of the GaN surface material. Under acidic conditions, the oxidation of KMnO4 for GaN surface was significantly stronger than that under neutral and alkaline conditions, and the GaN surface was effectively oxidized and corroded when the initial mass fraction of KMnO4 was 5 wt%. When the chemical and mechanical actions reached a synergistic effect, the oxide layer generated on the GaN surface was immediately removed by the Si3N4 ball and SiO2 abrasive, which led to a large increase in material removal rate (MMR); the COF curve tended to stabilize, and the average COF increased. The experimental results of the electrochemically assisted CMP of GaN were consistent with the friction and wear test results.

Layered Magnesium Phosphate as an Environmentally Friendly Solid Lubrication Additive: Morphology Control and Tribological Properties

To develop a new type of environmentally friendly solid lubricant and expand the high-value utilization of salt lake resources, we prepared a layered magnesium phosphate (MgHPO4·1.2H2O) eco-friendly lubricant using an improved green hydrothermal synthesis route in which particle size and morphology were controlled. The tribological properties of the layered magnesium phosphate samples as additives in PAO8 calcium-based grease were evaluated using an Optimol SRV-V oscillating reciprocating tester (hereafter referred to as SRV tester). Products exhibited excellent friction behavior when added to grease. When added at 3.0 wt %, the tribological properties of the grease were improved significantly; the highest operating load was raised from 400 to 600 N, the wear volume was decreased from 44.98 to 7.50 (10–4 mm3), and friction curves became more stable and smooth. A possible lubricating mechanism was proposed. Macro to micro analysis of rubbing surfaces showed that the MgP materials had a protective effect on the PAO8 calcium-based grease matrix, and lubricating films were clearly formed on the friction pair surface.

Nonlinear System Identification Using Audio-Inspired WaveNet Deep Neural Networks

Nonlinear system identification is a challenging task that requires accurate estimation of the structural model from observations of nonlinear behavior. The WaveNet, which was originally a neural network architecture for audio processing, has been modified and first introduced to the analysis of mechanical signals to capture long-term dependencies in mechanical systems and generate high-quality signals. A novel nonlinear system identification method has been proposed using a modified WaveNet-based approach that constructs a relationship between the vibration response and the nonlinear elements in the inverse model without the need for a definite structural model. This approach uses dilated convolution for feature extraction and a multilayer perceptron for feature transition, with the addition of average pooling along the time dimension for adaptive processing of varying length data, which are more computationally efficient and widely applicable. The 13-layer modified WaveNet models have been designed and applied to the problem. Comparisons with other baseline models were made to demonstrate the method’s superiority in terms of accuracy, effectiveness, and robustness. Additionally, the method has been applied to predict composite models of friction and elastic curves, demonstrating its ability to handle diverse and complex problems.

Effect of nitrogen content on the mechanical and biological properties of tantalum nitride coatings

In this article, the effect of nitrogen content on the mechanical and biological properties of Tantalum Nitride coatings has been studied. TaN coatings with different N concentrations were deposited on glass slides and medical metals by magnetron sputtering in Ar + N2 atmosphere to improve the adhesion strength and biocompatibility of PVD coatings. The morphology, composition, mechanical properties, and biology of the TaN films were characterized at varying N levels, which were obtained by adjusting the flow rate of N2 at 5, 10, and 15 sccm. Results showed that hardness of the coating increased when N2 was added. The film transitioned from γ-Ta2N to ε-TaN and δ-TaN when N2 gas flow rate increased. The γ-Ta2N coating had the highest hardness (37.30 GPa). The adhesion strength of the coatings was increased with N2 flow rate and then decreased, the ε-TaN film deposited at a N2 flow rate of 10 sccm had the highest adhesion strength (18.12 N). TaN coating deposited at a N2 flow rate of 10 sccm showed the highest cell growth rate (151.77 %) and number of cells on the surface. The friction curve of the δ-TaN coating subjected to 15 sccm N2 flow rate exhibited excellent wear resistance with minimum fluctuation. According to the aforementioned findings, TaN coatings deposited under various nitrogen flow rates have significantly improved in adhesion strength, wear resistance, hardness, and biocompatibility, which offers a good reference value for research on the surface modification of medical metal and a good replacement material for the field of medical implantation.

Deformation behavior of plasma sprayed Fe-based amorphous/ nanocrystalline coating under multi-scale tribological contact

Deformation behavior of Fe-based amorphous/ nanocrystalline coating synthesized by plasma spraying has been studied under multi-scale tribological contact. Nano- and micro-scale scratch investigation under constant and ramped loading revealed that deformation occurred mainly through plowing of coating surface by the probe. During low load (nano-scale) scratch tests, shear band generation was detected in the form of serrations in lateral force/ coefficient of friction curves under both constant (2 and 5 mN) and ramped (0–5 mN) loading conditions. Prominent shear bands around the scratch track with lesser fracture/ chipping were observed at high load (micro-scale) under ramped loading. Further, high load nanoscratch test under constant loading revealed aggravated fracture and chipping on the coating surface. Macro-scale deformation behavior studied using ball-on-disc dry sliding wear test at constant applied load (10 N) revealed that dominating wear mechanism in the coating was fatigue accompanied by abrasive and oxidative wear.

Nitrogen-Doped Carbon Dot as a Lubricant Additive in Polar and Non-polar Oils for Superior Tribological Properties via Condensation Reaction.

Nitrogen-doped lubricating additives have been proved to be an effective strategy to improve the tribological properties of lubricating oil. However, the traditional preparation methods of nitrogen-doped lubricating additives have the defects including harsh preparation conditions and a time-consuming preparation process. Herein, we report a preparation method of nitrogen-doped carbon dot (NCD) lubricating additives in a short time by one-step aldehyde condensation reaction at room temperature. The small size effect and nitrogen-containing functional groups of NCD lubricating additives provide favorable conditions for their dispersion and low friction in base oil. The tribological properties of NCD lubricating additives in sunflower oil (SFO) and PAO10 were systematically evaluated. The results show that NCD lubricating additives could reduce the average friction coefficient of SFO from 0.15 to 0.06 and PAO10 oil from 0.12 to 0.06, and the wear width is also decreased by 50-60%. In particular, the friction curve is very stable, and the friction coefficient was maintained at about 0.06 even under the working time of 5 h. By analyzing the morphology and chemical properties of the worn surface, the lubrication effect of NCDs is attributed to its small size effect and adsorption, which was easy to enter the friction gap to fill and repair. Furthermore, the doping of nitrogen induces the occurrence of friction chemical reactions, forming a friction film of nitrides and metal oxides at the friction interface, which effectively reduces the friction and wear of the surface. These findings provide a possibility for the convenient and effective preparation of NCD lubricating additives.

Microstructure and mechanical properties of FeCoCrNiAl0.1N high entropy alloy nitride coatings synthesized by cathodic arc ion plating using alloy target

To promote the industrial application of high entropy alloy nitride (HEAN) coatings, the cathodic arc ion plating deposition process was explored to deposit FeCoCrNiAl0.1 N using casting HEA alloy targets. We investigated the impacts of nitrogen pressure and bias voltage on the microstructure, mechanical characteristics, and friction behaviors. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to analyze the microstructures. It was found that compositions for all coatings were uniformly and the coatings mainly consisted of FCC-HEA, CrN, AlN, and FeN phases. The nano hardness and plastic deformation resistance, characterized by nano-indentation, both increased with the nitrogen pressure and certain bias voltage (<150 V). Coating deposited with 2.0 Pa and 150 V presented the maximum hardness of 32.9 GPa and the highest H3/E2 value of 0.1 GPa. The hardening mechanism was focused. Coatings deposited with low nitrogen pressure presented better crack resistance under scratch load. The friction behaviors were presented based on the combined studies of friction curves, wear track profiles, and morphologies. FeCoCrNiAl0.1 N coatings revealed excellent wear resistance with relatively lower COF (ranging from 0.43 to 0.51).

Rheology and breakdown energy of a shear zone undergoing flash heating in earthquake-like discrete element models

SUMMARYWe study the initiation and growth of a dry granular shear zone subjected to seismic shearing and flash heating from the perspective of a discrete element method. For this purpose, we created a semi-periodic numerical shear test similar to a rotary shear machine in which a 2 mm ×1.5 mm sample composed of micrometric cohesive disks is sheared in between two rigid walls. The strength of cohesive bonds is defined according to an elasto-brittle contact law calibrated to simulate peak and residual strength envelopes derived from rock mechanics tests. The sample is traversed by a pre-existing fracture and subjected to a vertical confining pressure (e.g. 112.5 MPa) and a velocity step function (e.g. 1 m s–1) applied on the top and bottom walls, respectively. Slip along the fracture induces the growth of a shear zone, which thickens by progressive abrasion of damaged material from cohesive blocks. We carried out two parametric studies to determine the rheology and physical properties of the shear zone for slip velocities and confining pressures characteristic of shallow earthquakes and several flash-heating temperatures. According to parametric studies, the mechanical behavior of the shear zone exhibits three distinct phases. The initial phase of rupture initiation is characterized by the propagation of a shear instability generated by the velocity step (phase 1). During this phase, friction and dilatancy curves are approximated by asymmetric peak functions whose amplitude and geometry are controlled primarily by confining pressure. In the intermediate phase of shear-zone growth, the sample displays an initial transient stage that asymptotically approaches steady state at submelting temperatures (phase 2). According to the inertial number, seismic shearing occurs under quasi-static conditions despite high shear rates. Thus, friction and dilatancy observed in all simulations are roughly constant regardless of slip velocity, confining pressure, and gouge zone thickness. In the final phase of shear weakening, the model evolves toward a new steady state at flash-heating temperatures (phase 3). Average friction and dilatancy are represented by sigmoidal decreasing curves that approach steady-state values lower than for phase 2. Predictably, the thermally weakened friction in steady state (μss ∼ 0.1) is close to the strength of frictionless granular samples sheared in quasi-static conditions. We calculate breakdown energies for the gouge and damage zones and the fracture energy at intermediate and high confining pressures. We show that breakdown energy fundamentally differs from fracture energy commonly used in seismology. The breakdown energy of the damage zones shows long-period damped oscillations weakly correlated with shear-stress fluctuations around average decaying values. Our results suggest that dilatancy is the primary energy sink within the damage zones at steady-state values. The breakdown energy components of the gouge zone follow a similar decaying trend as the average fracture energy but over a longer critical distance. Decohesion and dilatancy are the major energy sinks linked to gouge formation at intermediate pressures. In contrast, dilatancy and debonding frictional energies predominate at high confining pressures. Breakdown energy is equivalent to a fraction of fracture energy that nearly triples when doubling the confining pressure.

In vitro oral simulation based on soft contact: The importance of viscoelastic response of the upper jaw substitutes.

Real oral processing is the squeezing and shearing between two soft surfaces. The importance of soft palate surface cannot be ignored while focusing on tongue substitutes. Thus the effects of viscoelasticity, roughness of upper jaw substitutes, and fluid rheological properties on lubrication properties were explored by in vitro oral tribology experiments. Different palate substitutes significantly changed the friction curves of pure water, milk, and yogurt. The boundary friction coefficients of pure water and milk are higher under softer or smooth palate substitutes due to stronger viscoelastic responses of friction pairs. Their boundary friction coefficients are lowest at rigid upper jaw substitutes owing to smaller contact angles and deformation. However, the boundary friction coefficient of yogurt is lower owing to its high viscosity, low loss factor, and large particle size under soft friction pairs. In addition, it is highest at rigid palate friction pair because a smaller contact area reduces the entrainment of yogurt, resulting in poor lubricating performance.

Effect of argon gas environment on high temperature sliding wear characteristics of NiCrBSi laser clad

The martensitic stainless steels find extensive application in steam turbine blades, marine turbine blades, compressor blades etc. due to the optimum combination of strength and corrosion resistance. NiCrBSi alloy has been coated on AISI410 samples by laser cladding process. The tribological characteristics of the coated specimen were investigated against the WC-Co counter ball at 300 °C in the air and argon environments at 12.8 cm/s and 19.2 cm/s sliding velocities. The coated specimen was probed using XRD and scanning electron microscopy. In the argon environment, the wear loss was decreased by 36.84 % and 35.29 % for the sliding velocities of 12.8 cm/s and 19.2 cm/s, respectively, compared with the air environment. Irrespective of the sliding environment, a low wear rate and relatively stable friction curve were observed at higher sliding velocity, i.e., 19.2 cm/s compared to 12.8 cm/s. Oxidation played a major role in the wear loss of the coatings at high temperatures in the air environment, which decreased with the argon gas environment.

Wettability surface and friction characterisation of ZrO2 ceramics by femtosecond laser texturing

PurposeThe purpose of this study is to process the wettability surface of the ZrO2 ceramics to improve their surface friction performance.Design/methodology/approachMicrotexture was processed on the surface of ZrO2 ceramics using a femtosecond laser. The three-dimensional texture morphology, surface contact angle, friction curve and wear morphology were measured by the laser confocal microscope, the contact angle meter, the reciprocating friction and wear tester and the scanning electron microscope, respectively. Based on Wenzel and partial impalement models, a geometric model of micro pits is established to study the influence mechanism of micro pit depth, diameter and distribution density on wettability and to analyze the relationship between surface wettability and tribological properties.FindingsThe results show that changing the geometric characteristics of the texture will lead to a change in the solid-liquid contact mode, and then lead to a change of in the surface contact angle. Wettability is an essential factor that affects the reduction of surface friction. The construction of a reasonable texture can enhance the surface hydrophilicity, which is conducive to the formation of a lubricating film on the ceramic surface, thereby reducing abrasive and adhesive wear, and improving the wear resistance of the ZrO2 ceramic surface.Originality/valueThe results provide a theoretical reference for femtosecond laser surface texture wettability regulation and tribological performance improvement.

Ground-based observations of lightning-related X-ray/gamma-ray emissions in Florida: Occurrence context and new insights

Ground-based observations of energetic radiation (X-rays/gamma-rays) associated with natural lightning discharges are presented and discussed. The emphasis is placed on relating X-ray/gamma-ray emissions to specific lightning processes. X-rays/gamma-rays have been observed in the following three contexts: (1) final stages of the descending leader, (2) collision of opposite-polarity streamers at the onset of lightning attachments process, and (3) in-cloud processes giving rise to energetic radiation bursts characteristic of Terrestrial Gamma-ray Flashes (TGFs). In all three cases, the X-ray/gamma-ray production involves runaway electrons and can be materially influenced (enhanced) by the presence of previously created but decayed lightning channels. Such channels are characterized by elevated temperature (about 3,000 K vs. 300 K for ambient air), which significantly lowers the friction curve (representing the spatial rate of electron energy loss), so that its peak is an order of magnitude lower than that for cold air. As a result, in the electric field of about 4 MV/m (such and even higher fields are briefly produced near the tips of lightning leaders), ambient electrons can be accelerated over the friction-curve peak to the keV range and further to relativistic energies needed for production of X-ray/gamma-ray emissions. Significant avalanching of runaway electrons seems to be possible. For one very intense (55 kA) subsequent stroke, which was a prolific X-ray/gamma-ray producer, we estimated the spatial extent of strong (>4 MV/m) electric field region associated with the descending leader tip to be about 1.5 m, which is sufficient for multiplication of runaway electrons by a factor of 2 × 104 or so.

Study on the damage evolution of fretting wear in an Inconel 718 laser cladding alloy layer at different temperatures

In this study, Inconel 718 alloy samples were prepared by laser cladding deposition technology, and GCr15 steel balls were selected as the friction pair. The tangential fretting wear tests were conducted in ball-on-flat point contact mode using a self-developed multifunctional fretting wear tester. The damage evolution law of fretting damage with the number of cycles for laser cladding Inconel 718 alloy was investigated at room temperature (RT) and 400 °C. The obtained results reveal that the coefficient of friction curves and energy dissipation value in the process of fretting wear first increased, then decreased, and finally reached a stable state with increasing cycles. At room temperature, the fretting running states gradually changed from mixed slip regime (MSR) to gross slip regime (GSR). There was clear spalling in the fretting damage zone, and a large mass of wear debris was formed on the worn surface. As the test time continued, the width and depth of the wear marks gradually increased, the volume of material wear increased, and the wear damage of the material gradually aggravated. When the test temperature was 400 °C, the fretting was running in the MSR. As the number of cycles increased, spalling and adhesion of wear debris occurred in the fretting damage zone. The main mechanisms of fretting wear were oxidation wear, abrasive wear, fatigue wear and adhesive wear.

Effect of Laser Surface Texturing on the Tribological Properties and Scuffing Mechanism of CKS Piston Ring Against Cast Iron Cylinder Liner Under High Intensifying

The objective of this study is to characterize and understand the evolutionary processes that the effect of surface texture has on the tribology properties of the Chrom-Keramik-Schicht (CKS) piston ring/cast iron cylinder liner system under high intensifying. Surface dimple textures with an area density of 3–9% were prepared on the CKS piston ring by YAG laser, and the antifriction and antiscuffing properties were tested on a reciprocating test rig at 200 °C and 80 MPa. The minimum friction coefficient and wear loss were both obtained at the area density of 5%, compared with the untextured cylinder liner–piston ring (CLPR). The friction coefficient decreased by 0.013 to 0.086, and the wear loss for the piston ring and cylinder liner decreased by 41% and 46%, respectively. The sharp decrease of the friction force induced by surface polishing of the cylinder liner is taken as a sign to indicate the cylinder scuffing under starved lubrication. The scuffing time for the piston ring/cylinder liner system reached a maximum value of 18 min at an area density of 3%, which is extended about 41% compared with that of the untextured piston ring. The dimple surface texture on the piston ring could extend the scuffing time by delaying the occurrence of polishing behavior on the surface of cylinder liner. It is found that the retarded surface polishing played a major role for the modification of the antiscuffing property of the friction pairs according to the friction curves and wear morphologies.

Аналитическое выражение для аппроксимации силы трения виброзащитного механизма сиденья оператора

In mathematical modeling of dynamic and vibration protection systems of operators of construction and road machines, it is necessary to take into account the damping properties of the mechanisms. Accounting for the friction force in mathematical models is often performed using a coefficient, according to the viscous friction model. In more complex models, it is common to use a well-known expression in which the functions of the exponent and hyperbolic tangent are present, and the independent parameters are the Coulomb and separation friction forces, the separation friction rate, and the coefficient of viscous friction. This expression is used in a well-known mathematical package. However, the well-known expression does not accurately approximate the experimental friction curves. In the present work, an alternative expression for the total friction force has been supplemented. The refinement made it possible to apply a new formula for the entire range of change in the velocity argument and more accurately reproduce the characteristic shape of the experimental friction characteristics. For the new expression, complementary formulas were obtained that establish the relationship between the input parameters and a number of others that have a clear and simple physical meaning of the parameters. A comparison was made of the generally accepted and proposed expressions according to experimental data, graphs of the relative error were constructed. Also, a comparison of two expressions of the total friction force was made, as an example, on a dynamic model of forced oscillations of a concentrated mass on a moving base. The comparison results showed a significant discrepancy between the generally accepted expression in comparison with the proposed one, in terms of the total friction force, as well as a discrepancy in the amplitudes of relative displacements and absolute mass accelerations obtained on the dynamic model. The proposed expression can be used to approximate the total friction force in mathematical models of dynamic vibration protection systems for operator seats.

Study of Adhesive Wear Test on TiSi, AlTi, and WTi Coatings

Coatings based on Ti, Si, W, and Al synthesized by different techniques have been investigated in order to better understand their properties; however, there are few results related to their wear behavior. In this paper, TiSi, AlTi, and WTi coatings were applied by means of a sputtering system on 316L stainless steel substrates in order to evaluate their behavior through a ball-on-disc wear test. Adhesive wear tests were carried out using the ball-on-disc technique, which allowed the coefficient of friction to be measured. The morphological characterization was based on an analysis of the SEM images and on the optical profilometry of the wear traces of the coatings, used to calculate the wear rate. An analysis of the wear products was carried out based on information provided by the SEM-EDS, Raman spectroscopy, and XPS techniques, which provided information about the tribo-chemical behavior of the coatings subjected to the ball-on-disc test. The morphological analysis showed that the TiSi and AlTi coatings exhibited premature failure, which was corroborated by means of the coefficient of friction curves. It was also observed that the WTi coating exhibited better behavior against the wear test, with a coefficient of friction lower than that of the stainless-steel substrate, without showing evidence of premature failure, which can be explained as a consequence of the tribo-chemical behavior of the WxOy produced in the coating.