Sliding Wear Tests Research Articles

Effect of occlusal adjustment and subsequent repolishing on the surface roughness and volumetric wear of different types of glazed monolithic zirconia after chewing simulation

The objective was to evaluate the effect of material (four monolithic zirconia) and surface condition [glazed (G) versus polished after simulation of occlusal adjustment (GAP)] on roughness and volumetric wear (VW) of dental zirconia after chewing simulation (CS). Zirconia specimens (ZS) were fabricated with an approximate diameter of 12.0 mm and a thickness of 1.0 mm. The four types of monolithic zirconia utilized were Prettau 4 Anterior (PA), Lava Plus (LP), Cercon hT (hT), and Cercon xT (xT). All specimens were coated with a thin and uniform layer of Prettau Plus glaze. Additionally, half of the ZS underwent a simulation of occlusal adjustment followed by clinical polishing. The sliding wear test was performed using a chewing simulator set at 30 N, 2 Hz, and 500,000 cycles, employing steatite specimens (SS) to simulate opposing dentition. ZS and SS underwent topographic analysis through optical profilometry to assess volumetric wear (VW) and surface roughness. The average roughness values (μm) of the zirconia ranged from 0.38h (PA-G before CS) to 2.55a (PA-GAP after CS), while for the antagonist the values ranged from 1.3b (LP-G before CS) to 2.6a (PA-GAP after CS). The VW values (mm3) of the ZS ranged from 0.7b (LP-G) to 2.5a (LP-GAP), while for the antagonist the values ranged from 0.17a (xT-GAP) to 0.33a (LP-G). The CS increased the roughness of all materials tested, regardless of the surface condition. The glazed condition showed lower roughness than the glazed/occlusal adjustment/polishing condition before the CS for three zirconia (PA, LP and xT) and after the CS for all materials. The surface condition did not significantly influence volumetric wear (VW) for three materials (PA, hT, and xT); however, for the Lava Plus (LP) group, the glazed condition resulted in reduced VW. The VW of the SS was unaffected by the material type or surface condition. In summary, zirconia specimens that underwent occlusal adjustment followed by repolishing demonstrated increased surface roughness compared to the glazed ones, while their wear behavior varied depending on the type of zirconia used.

Annealing temperature-dependent microstructure, mechanical, and tribological properties of intercritically heat-treated dual-phase steel

Abstract This study investigates the role of intercritical annealing temperature on microstructural characteristics, mechanical performance, and wear resistance of DP1000 steel. As-received DP1000 steel samples in cold-rolled conditions were subjected to intercritical annealing between 730 and 880 °C with an interval of 30 °C, followed by water quenching. After heat treatment, the specimens were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), mechanical tests consisting of hardness, impact, and tensile tests, and dry sliding wear tests. The findings revealed that equiaxed ferrite grains replaced elongated ones, and the martensite ratio increased from 21% up to 64% with increasing annealing temperature. Due to the formation of equiaxed grains, the impact strength was at least doubled for each specimen by heat treatment, reaching a peak value (9.55 J cm−2) at 760 °C. The hardness (311 HB) and tensile strength (1007 MPa) of the as-received sample were higher than that of the annealed steels up to 820 °C. The mechanical strength of the samples improved at 850 and 880 °C by approximately 10%, and accordingly, the lowest wear rate was obtained at the specimen annealed at 850 °C. The increase in temperature up to 880 °C caused a decrease in wear resistance due to excessive brittleness.

Finite element analysis of sliding wear on the borided AISI 316L stainless steel

This work implements a 3D finite element to analyze wear in borided AISI 316 L stainless steel. The 3D model was validated through sliding wear test under a ball-on-flat configuration, following the ASTM G133 standard procedures. ABAQUS software was used with an Arbitrary Lagrangian-Eulerian (ALE) remeshing technique alongside the UMESHMOTION subroutine to apply an elemental level Archard’s equation. The artificial roughening of the worn surfaces due to discretization in finite element sizes was controlled by relating the maximum increment time on each wear step to the element size and the stroke. The study also described the evolution of the stress field and the behavior of the contact area. The maximum stress was estimated after the first indentation, decreasing as the contact area increased, reaching a minimum at the last wear step. The results revealed a good correlation between the experimental and modeled data, with a maximum error of 8.34% in the contact stress and a maximum error of 22% in the wear depth.

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

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

Effect of ionic liquid on dispersion stability and antiwear behavior of CuO nanoparticles added to polyalphaolefin base oil

The experimental study assessed the impact of choline chloride cation-based ionic liquid (IL), on the dispersion stability and wear characteristics of copper (II) oxide (CuO) nanoparticles (NPs) in synthetic base oil (PAO 10). CuO NPs, averaging 50 nm in size, underwent surface modification using varying concentrations of the IL (0.25%, 0.5%, 0.75%, and 1% by weight). The formulations were subjected to sliding wear tests to evaluate their wear behavior. Analysis of the worn surfaces utilized scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy. The results indicated that the combination of 0.75% IL and 1% CuO NPs provided optimal dispersion and exhibited effective surface mending, enhancing wear protection by 21.1% than that of PAO 10. The formulation containing 1% IL and 1% CuO NPs demonstrated the highest load carrying capacity among all tested compositions. In terms of wear behavior, the nanolubricant formulations with 0.75% and 1% IL outperformed the lubricant formulation containing 1 wt% of the commercial antiwear additive Zinc dialkyldithiophosphates (ZDDP).

An investigation on tribology performance of Abutilon Indicum fibre reinforced polymer composites

This research work investigates the tribological characteristics of Abutilon Indicum Fiber (AIF) reinforced composites with epoxy as the binding agent. The Abutilon Indicum fiber reinforced composites were manufactured by compression molding technique. These composites were fabricated by varying the fiber volume fraction ranging from 5%, 10%, 15% and 20% respectively and considering the fiber length as a fixed factor due to its short length. This research paper illustrates the effects of different fiber volume fractions (5,10,15 and 20%) on the tribological properties such as Specific wear rate (SWR) and Coefficient of friction (µ) of Abutilon Indicum fiber reinforced composites. Sliding wear tests were carried out under dry environment conditions with pin-on-disc wear testing machine. The experiments were performed for each composite with different combinations of testing parameters, sliding loads (10, 20 and 30 N); sliding distances (1,2 and 3 km); sliding speeds (1,2 and 3 m/s). Shore D hardness of 78.22 is determined to be higher for 15% volume fraction of AIF composites. Results conclude that the addition of AIFs in these composites enhanced the tribological performance with good wear resistance in relation with the pure epoxy-based composites with 15% volume fraction of AIFs displaying best results with higher resistance to wear at various operating conditions. Composites produced with 20% volume fraction displays the effects of fiber agglomeration which in turn has an inverse effect on hardness; limits the wear resistance with higher friction and wear rate and such results agree well with the wear debris, pits and contact patches in micrographs. Optimal fiber volume fraction of 15% was suggested in fabrication of composites for usage of AIFs as friction material.

Effect of Laser Surface Texturing Process on Dry Sliding Wear Behavior of NiTi Shape Memory Alloy Used in Airplane

In this study, the effect of laser surface texturing (LST) applied to NiTi Shape Memory Alloy (SMA) on the dry sliding wear behavior of the material was investigated. After polishing and cleaning the material surface, a pitted surface texturing process was performed using a femtosecond laser under atmospheric conditions. After the surface texturing process, dry sliding wear tests were performed at room temperature. When the wear behavior of the laser-applied and non-laser-applied test samples was evaluated comparatively, it was determined that the coefficient of friction (COF) of the laser-applied samples under 1N load was approximately 17% lower. It was determined that the decrease in the COF value decreased with increasing load. However, the wear amount of the LSD-applied NiTi SMA was higher than the untreated sample. It was evaluated that this situation was due to thermal softening that occurred depending on the ablation geometry and dimensions.

The improvement of dry sliding tribological properties by designing nano-primary cementite in bainitic/martensitic matrix microstructure in hypereutectoid PM components

The production of nano-sized primary cementite in bainite/martensite matrix (NCBM) microstructure was designed to improve the dry sliding wear properties of high carbon PM parts. A different heat treatment cycle was carried out for the production of novel the NCBM microstructure. High purity iron powder 1.5 wt%. natural graphite powder was added and it was compacted in the form of a dry sliding wear test specimen in a mold and sintered at 1200 °C in a pure Ar gas atmosphere. The novel NCBM microstructure in the PM material was produced by quenching at 950 °C, then annealing at 600 °C for 12 min, then quickly cooling from 730 °C to 250 °C in a salt bath and keeping it isothermal for 100 s. The friction coefficient of materials with NCBM microstructure was less than other samples. It was found that while the wear coefficient were higher in the tempered martensitic microstructure sample having higher hardness, they were less than in the sample having bainitic/martensitic microstructure with similar hardness.

Mechanical Properties and Tribological Study of Bottom Pouring Stir-Cast A356 Alloy Reinforced with Graphite Solid Lubricant Extracted from Corn Stover

The present work epitomises extracting the graphite (Gr) solid lubricant from the corn stover. The extracted Gr was incorporated as reinforcement in the A356 alloy (Al-7Si), and the effect of the Gr particles on the mechanical and tribological properties was investigated. In spite of this, the input process parameters for the dry sliding wear test at room temperature against the EN31 steel disc were optimised through ANOVA analysis. The fabricated A359—X wt% (X = 0, 2.5, 5, 7.5) composite through bottom pouring stir casting techniques was analysed microstructurally by using XRD and FESEM analysis. The micro Brinell hardness and tensile strength were investigated per ASTME10 and ASTME8M standards. A wear test was performed for the composite pins against the EN31 steel disc according to ASTM G99 specifications. The XRD analysis results depict the presence of carbon (C), aluminium (Al), and silicon (Si) in all the wt% of the Gr reinforcement. However, along with the elements, the Al2Mg peak was confirmed for the A356—7.5 wt% Gr composite and the corresponding cluster element was confirmed in FESEM analysis. The maximum micro Brinell hardness of 92 BHN and U.T.S of 123 MPa and % elongation of 7.11 was attained at 5 wt% Gr reinforcement due to uniform Gr dispersion in the A356 alloy. Based on the ANOVA analysis, the optimal process parameters were obtained at 20 N applied load, 1 m/s sliding velocity, and 1000 m sliding distance for the optimal wear rate of 0.0052386 g/km and 0.364 COF.

Wear simulation of pin-on-disc sliding wear test

Wear simulation of pin-on-disc sliding wear test

An experimental and analytical approach to study the sliding wear performance of epoxy composites with steel wire and glass fiber reinforcement

This study investigates the sliding wear behavior of hybrid epoxy composites reinforced with alternating layers of glass fiber mats and steel wire mesh. The objective is to enhance the wear resistance of glass fiber-epoxy composites with the incorporation of steel wire mesh. Three composite types with different stacking sequences are fabricated using the hand layup technique. Dry sliding wear tests are conducted using a pin-on-disc test rig under various operating conditions, following to ASTM G99 standard. Taguchi analysis with L25 orthogonal array identifies sliding velocity as the most influential factor on wear rate, followed by normal load. Steady-state wear analysis is performed to evaluate the effect of each significant factor independently. Analysis of variance results show sliding velocity significantly affects wear rates, contributing 67.63% for glass-epoxy composite (G11) and more than 75% for glass-steel-epoxy hybrid composites (G7S4 & G4S7). A regression model, based on experimental data, predicts specific wear rates with error margins of 3.17% for glass-epoxy composite and less than 2% for glass-steel-epoxy composites. Additionally, electron microscopy is used to analyze worn surfaces, revealing the primary wear mechanisms.

Evaluation of Residual Stress in Stir-squeeze Cast Aluminium – Fly Ash Composites Using X-Ray Diffraction Method

Determination of residual stresses in metals, subjected to secondary processing, is necessary from the point of view of their applications and is widely studied in literature. However, residual stresses induced during service is generally ignored when evaluating the performance of the component. The residual stress in a component could be tensile or compressive in nature and eventually affects its service life under external loading. In this regard, industries demand rapid, efficient, and easier methods of non-destructive testing to identify and control the residual stress in such components. The present work aims at evaluation of residual stress in an LM-25 aluminium alloy/fly Ash Metal Matrix Composites (AMC) after subjecting the specimen to dry sliding wear tests. X-ray diffraction technique was used to measure the residual stress in the “pin” specimen of the pin-on-disc set-up. The residual stress was ~ 24 % higher in the composite compared to the un-reinforced alloy after the wear test while the wear rate, measured in terms of weight loss of the pin, was lower by about 50%, under similar test conditions.

Experimental study on tribological behavior of a binderless cemented carbide at high contact stress

Knowledge of frictional evolution and associated damage mechanism during sliding wear conditions using binderless WC-based cemented carbide is lacking. In this study, the frictional evolution and corresponding transformation of microstructure, and wear mechanisms of Al2O3/WC-based cemented carbide due to the effect of different contact pressure, especially high pressure have been explored using a reciprocating ball-on-flat sliding wear tester, which was experimentally simulated following the ASTM G133–02 standard. The dynamic curves in friction coefficient with the sliding time were described. The microscopic 3D topography of contact surface was obtained by the MFP-3D atomic force microscope. The material removal and the wear rate were discussed. Worn surface morphologies at different moments, cross-sectional images of wear tracks at different loads, and wear debris were taken by field emission scanning electron microscope. The results suggested that the pressure plays a decisive role in frictional evolution and wear characteristics. Two models of frictional evolution were declared. A novel “surge” phenomena in friction coefficient was found and explained at high contact pressure. Wear transition from mild wear to severe wear was confirmed. More than one wear mechanism was observed, including micro-cutting (polishing), generation and propagation of cracks, cracking-induced spalling, plastic deformation, and the formation of tribolayer.

Comparison of tribological performance of hard chrome and heat-treated electroless Ni–P platings

The search for alternatives to hard chrome platings, which have been used in the aviation sector for an extended time but have begun to be abandoned due to their negative effects on human and environmental health, has continued in recent years. Hard chrome plating's primary application in the aviation sector is for wear performance. Electroless Ni–P platings lack the necessary hardness and wear resistance compared to hard chrome platings. The purpose of this study was to determine whether these coatings might be used in place of hard chrome plating and to determine how heat treatment affected the tribological performance of electroless Ni–P platings applied to steel substrates. Hard chrome and electroless Ni–P platings were applied to five different steel substrates. The coatings’ microstructure, bending, corrosion resistance, hardness, and dry sliding wear tests were conducted. It has been shown that heat treating the Ni–P platings can result in appreciable increases in hardness and tribological performance. In the heat-treated coatings, hardness values were higher than those of the hard chrome platings. It was concluded that although hard chrome plating showed better wear resistance, heat-treated electroless Ni–P platings have the potential to compete with hard chrome platings in terms of tribological performance.

Tune Al/Ti to adjust FCC+L21 hetero-structured Ni-based high-entropy alloys for improved mechanical properties and wear resistance

Outstanding mechanical properties of Ni-based superalloy benefit from its coherent γ/γ’ structure via precipitation strengthening of γ matrix (FCC structure) by L12 Ni3Al-type γ’ phase. Back-stress strengthening is another effective strategy to further enhance the FCC+L12 structured Ni-based superalloy. In this work, we extend such approaches to high-entropy alloys (HEAs) by introducing different Al and Ti contents (5 at.% ∼18 at.%) into a Ni-based CrFe2Ni4 alloy to form FCC+L21 heterostructured AlxCrFe2Ni4Tiy HEAs. Detailed microstructural analysis indicates that L12 Ni3(Al,Ti)-type nanoparticles form in a (Ni,Fe,Cr)-rich FCC matrix. The volume fraction of L21 AlNi2Ti-type phase can be varied by adjusting the Al/Ti ratio and concentrations of Al and Ti. Higher Al and Ti contents promote L21 phase formation and higher Al/Ti ratio (>1) prohibits the high Ti-containing compounds such as D024η-Ni3Ti and C14 Laves Fe2Ti phases, which are hard but brittle. Corresponding Young's modulus, Poisson's ratio, hardness, and the bulk to shear modulus ratio (B/G) can be readily modified. Compressive tests demonstrate that Al1.5CrFe2Ni4Ti1.0 alloy with half FCC and half L21 phases possesses the optimal strength-ductility combination (with compressive yield strength of ∼1564 MPa and fracture strain of ∼28 %). DFT calculations were performed to elucidate relevant mechanisms. Sliding wear tests were also performed, which demonstrate superior wear resistance of the HEAs at both room and elevated temperatures, compared with a commercial Ni-based superalloy, UHT-Nickel.

Influence of Ni content on electrochemical corrosion and tribological behavior of Cu-10Sn coatings by laser cladding

In this work, Cu-10Sn-xNi (x = 0, 3, 6, 9, and 12 wt%) alloy coatings were prepared using laser cladding technology. The influence of Ni content on the phase composition, microstructure, crystallographic characteristics, microhardness, electrochemical corrosion, dry sliding wear and corrosive wear behavior of the coatings were studied. The results indicated that the coatings formed good metallurgical bond with the substrate. The coatings were composed primarily of the α-Cu matrix and small γ precipitates. The Ni element effectively reduced component segregation, and with the increased of Ni content, the grain size in the coating was significantly refined, resulting in fine equiaxed grains. Under the effect of fine grain strengthening, the Cu-10Sn-12Ni (C12NS) coating achieved a higher microhardness of approximately 222.9 ± 5.3 HV0.2. In the electrochemical corrosion test, the increased in the number of grain boundaries significantly reduced the corrosion resistance of the Cu-10Sn-xNi coatings. The Cu-10Sn-6Ni (C6NS) coating exhibited excellent corrosion resistance, with an Icorr of only 1.37 μA/cm2. The results of the dry sliding wear test showed that under the influence of the hardness gradient between the hard precipitate phase and the soft matrix of the coating, the C6NS coating achieved satisfactory wear resistance with a specific wear rate of 3.30 × 104 μm3/Nm. Meanwhile, due to the good corrosive resistance, the C6NS coating showed the best tribological performance in 3.5 wt% NaCl environment, and the specific wear rate was 1.58 × 104 μm3/Nm.

Microstructure and tribological behavior of Al–TiC composite strips fabricated by a multi-step densification method

This study aims to enhance the tribological properties of automotive applications by examining the effects of TiC content on the microstructure, mechanical properties, and wear behavior. This study investigates the production of Al–TiC composite strips using a novel multi-step densification process combining mechanical alloying and hot rolling with TiC concentrations ranging from 0 to 12 vol%. The novelty of this work lies in its comprehensive approach to developing and analyzing Al–TiC composite strips using a multistep densification method. This study integrates microstructural analysis, mechanical property evaluation, and detailed tribological behavior assessment under different wear loads (5–25 N). A key innovation is the application of the Abbott Firestone method to analyze worn surfaces, providing insights into optimal wear conditions. The study reveals that increasing the TiC content to 12 vol% significantly improves densification, hardness (up to 268.8% increase), and wear resistance (up to 95% improvement at a 5N load). Dry ball-on-flat sliding wear tests at loads of 5–25N demonstrate that TiC particles hindered complete delamination wear in the composite strips. The Abbott Firestone method analysis of worn surfaces indicated an optimal exploitation zone in the Al-6 vol% TiC composite at both low and high wear loads. This comprehensive approach provides valuable insights into optimizing Al–TiC composites for enhanced performance in automotive components that require improved wear resistance.

Tribological performance of ZrO2 nanoparticles as friction and wear reduction additives in aviation lubricant

Abstract High-performance aircraft engines require superior aviation oils to enhance their lubricating performance and prolong service life. Addition of nano-sized ceramic particles has been considered as a useful way to improve the tribological performance of base fluids. Up to now, few previous studies focused on the tribological properties of ZrO2 nanoparticles in aviation oil. The current study dispersed ZrO2 nanoparticles into PAO20 aviation base oil as lubricant additives. A dual-step method comprised of physical blending and ultrasonic dispersing was applied in the preparation of ZrO2 nanofluids. Oleic acid was utilized as surfactant to enhance the stability of ZrO2 nanofluids. Ball-on-plate reciprocating sliding wear tests were conducted to obtain the coefficient of friction and wear volumes. It was found that the PAO20 base oil produced the highest coefficient of friction of 0.278 and wear volumes of 2.305╳10-2 mm3. 5wt% ZrO2 nanofluids with 5wt% oleic acid showed the best lubricating performance. The coefficient of friction was reduced by 31.29%, and wear volume was reduced by 42.95%. In the examination of wear tracks, a physically embedded tribo-layer of ZrO2 nanoparticles and an oleic acid tribo-film with low shearing resistance were formed, which lowered the friction, and protected the mating surfaces against abrasive and adhesive wear. The results obtained in this study have applicable values in the development of high-performance aviation lubricants.

Optimization and Analysis of Dry Sliding Wear Behavior of AlCrTiSiN Coated SKD61 Steel Using Response Surface Methodology

The aim of this research is to investigate the wear behavior of SKD61 steel coated with AlCrTiSiN using the Filtered cathodic arc plasma deposition coating method while adhering to VDI 3198 standards for coating adhesion assessment. Dry sliding wear tests, conducted according to ASTM G133-05. The experiment is designed using response surface methodology (RSM) to determine the response parameter as the wear rate, with independent parameters of interest including load, sliding velocity, and sliding distance ranging from 5 to 11N, 0.1 to 0.2 m/s, and 250 to 550 m, respectively. Additionally, wear characteristics are analyzed using SEM-EDS analysis. The wear test results demonstrate that load had the most significant impact on the wear rate, followed by distance and speed, respectively. The target of achieving minimal wear rate was attained with a load of 5 N, a sliding velocity of 0.11 m/s, and a sliding distance of 550 m. Model significance testing revealed that the determination coefficient (R2) and adjusted determination coefficient values, indicating the accuracy of the model, were equal to 93.96% and 88.53%, respectively.

Microstructure, hardness, and tribological properties of Ni-Co/ SiO2 nanocomposite coating produced through pulsed current electrodeposition

This study investigates the development of Ni-Co/SiO2 nanocomposite coatings on mild steel surface using pulsed-current electrodeposition method. The effects of incorporating SiO2 nanoparticle and varying its concentration on the coatings' microstructure, microhardness, wear resistance, and frictional properties were assessed using field-emission electron microscopy, X-ray diffraction, Vickers microhardness testing, and dry sliding wear tests. The results indicated that the coatings exhibited two-phases of Ni-Co solid solution (α) with a face-centered cubic (FCC) crystal structure and hexagonal Co, a refined crystallite size of approximately 31 nm for Ni-Co and about 25 nm for Ni-Co/SiO2, along with a colony-like morphology that did not show any preferred growth direction. The amount of Ni-Co solid solution increased with the addition of SiO2 nanoparticles. The composite coatings demonstrated enhanced microhardness of 581 HV, which is 52 % greater than that of the Ni-Co coating, as well as improved wear resistance and a reduced friction coefficient compared to the unreinforced alloy coating. However, higher SiO2 content adversely impacted the tribological properties due to nanoparticle agglomeration. Analysis of the worn surfaces revealed a transition from abrasive wear to oxidative wear with increasing applied force for the coatings.