Counterface Material Research Articles

Tribological behavior of Fe40Mn20Cr20Ni20 HEA sliding against various counterface materials

Wear is a failure factor that must be considered when alloys are in service, especially as moving parts. However, few current studies have addressed the tribological behavior of HEAs in service with tribo-pair systems consisting of materials in contact with them. Therefore, in this work, the tribological properties between Fe40Mn20Cr20Ni20 HEA with four typical counterfaces consisting of tribo-pair systems were investigated at room temperature, i.e., hard alloy (WC/Co), metal (GCr15 steel), ceramic (Si3N4) and plastic (POM). It was found that there were significant differences in the wear mechanisms between various tribo-pair systems. Moreover, adhesive wear dominates the wear extent of the alloys. The wear rate of the alloy after sliding with WC/Co or GCr15 even reached 20–30 times higher than that after sliding with Si3N4, indicating that the sliding contact of the alloy with WC/Co or GCr15 is not an optimal design during service. In addition, the frictional oxidation that occurs during sliding contact played good lubrication role. In tribo-pair systems consisting of Fe40Mn20Cr20Ni20 HEA with WC/Co, GCr15 or Si3N4, the average coefficient of friction exhibited a tendency to decrease with the normal force.

Friction mechanisms of Ni-based and Zr-based bulk metallic glasses under different contact pressures

Pin-on-plane dry friction tests of Ni-based and Zr-based bulk metallic glasses were performed at ambient temperature under reciprocating sliding condition at 4 mm/s, under 160 MPa and 290 MPa. Domed 100Cr6 steel pins were used as counterface material. The friction performance of Ni-based glass is worse than the Zr-based glass but the former has a relatively more stable feature. For all metallic glasses, lower friction and more stable process can be observed upon higher contact pressure. Transfer of material from metallic glass samples onto steel pin surfaces is analyzed in details at the micrometer scale, showing that tribological properties of metallic glasses at high pressure could be related to the volume hardness of materials, together with the glass transition temperature.Keyworks:Metallic glasses, Third body flow, Wear, Friction performance

Dry sliding wear and friction performance of zirconium dioxide tribopairs

Zirconium is an attractive engineering material owing to its commendable temperature, corrosion resistance, and excellent biocompatibility. Despite these merits, its industrial applicability is hindered by elevated wear and friction in tribological settings. Previous research has concentrated on unmatched pair contacts involving zirconium and alumina primarily due to the exceptional hardness. However, there is a noticeable dearth of literature on the matched pair contact condition for zirconium dioxide. Thermal oxidation is a promising and cost-effective method to address the suboptimal tribological performance and enhance the mechanical and electrochemical properties of zirconium. In this study, thermal oxidation is employed to produce a 6-μm-thick oxide layer in an air furnace at 650°C for 6 h. Subsequently, the resulting surface coating was tribologically tested using a pin-on-disc tribometer against two distinct counterface materials, namely, alumina and zirconium dioxide, in a dry and unlubricated environment. The findings reveal that matched contact between the zirconium dioxide tribopair is unfavorable, leading to elevated friction and wear rates. Consequently, this configuration should be avoided in dry contact situations characterized by high contact pressures. However, under lower contact pressures, the wear performance is acceptable. Furthermore, when combined with lubrication, this system may have potential applications in bio-tribological systems.

Tribological Analysis of Steels in Fuel Environments: Impact of Alloy Content and Hardness

The performance and durability of high-pressure fuel systems in combustion engines are critical for consistent operation under extreme conditions. High-pressure fuel systems are traditionally lubricated with fuel that is compressed and delivered to the combustion chamber. However, lubrication with fuel presents significant challenges in these systems when used with low-viscosity fuels, leading to increased wear rates, especially in reciprocating contacts. This study delved into the tribological performance of steels of varying alloy content (annealed and hardened variants of AISI-52100, CF2, and D2) against alumina and hard 52100 counterbody materials in ethanol and decane environments. Friction and wear behaviors were evaluated, highlighting the influence of material interactions and environmental factors. Elastohydrodynamic lubrication analysis of the tested systems indicated that ethanol and decane form lubricating films of nanometer-scale thickness, confirming the boundary lubrication regimes of the performed tests. In summary, the tribological behavior trends were similar for alumina and 52100 counterbodies. Even though soft 52100 steel demonstrated low friction, its wear was the largest for both tested environments and counterface materials. Among all the tested materials, hard D2 experienced the lowest wear. 52100 and D2 steels showed opposite friction change behavior when comparing hard and soft samples, with lower friction observed for softer 52100 steel and harder D2 steel. Meanwhile, the wear was lower for harder candidates than for softer ones independent of the environment and counterbody material. Raman spectroscopy analysis of the formed wear tracks indicated the formation of carbon films with larger intensities of characteristic carbon peaks observed for more wear-resistant materials. These results suggest the synergistic effect of hardness and tribochemical activity in reducing the wear of materials.

Study on the role of chromium addition on sliding wear and corrosion resistance of high-manganese steel coating fabricated by wire arc additive manufacturing

Guide shoe made of steel is an important component of coalcutter and rail transport to sustain forward direction. However, the guide shoe suffers from wear failure due to the heavy load and fatigue. Preparing wear-resistance coating on the worn surface is a practical and economic technology to elongate longevity. High manganese steel is a candidate material with excellent wear resistance. In this study, high-manganese (HiMn) and high-manganese medium-chromium (HiMnMeCr) coatings are fabricated by using wire arc additive manufacturing (WAAM) to investigate the role of Cr addition on the microstructure and resistance to wear and corrosion by analyzing the microstructure morphology, wear rate, coefficient of friction, surface and cross-sectional morphology of the wear track, and electrochemical behavior by using sliding wear test and electrochemical experiment. The experimental results obtained by using the counterface material of ZrO2 showed that Cr addition changed the microstructure constitutes of WAAMed HiMn coating from biphasic austenite + martensite to single austenite. The addition of Cr elongated the running-in period of the wear process and weakened the wear resistance of the WAAMed HiMnMeCr coating due to the work-hardening effect induced by the severe plastic deformation of austenite. At loads of 50 and 100 N, the primary wear mechanism for the HiMn coating was a complex mode of abrasive and adhesive wear. The wear mechanism transformed into a single adhesive wear at a load of 120 N. However, the primary wear mechanism of the HiMnMeCr coatings was abrasive wear at all tested loads. The electrochemical experiment (pote ntiodynamic curves and EIS analysis) shows that the corrosion resistance of HiMnMeCr coating was better than that of HiMn coating, indicating that the addition of Cr enhanced the corrosion resistance of the WAAMed HiMn steel by the passivation effect of Cr. This study will provide a fundamental theory for the fabrication of wear-resistance coating by using WAAM.

Effect of V doping on the high temperature tribological properties of (Ti1−xVx)3AlC2 solid solutions sliding against different counterparts

The effects of Al content and the counterface material on the high temperature tribological behavior and wear mechanism of (Ti,V)3AlC2 solid solutions were investigated. The friction coefficient of (Ti0.6V0.4)3AlC2 is reduced by 36.25% and 47.76% compared to Ti3AlC2 at room temperature and 800 °C respectively. When coupled with Al2O3 and ZrO2 balls at 800 °C, continuous smooth lubricating films composed of oxides formed by the tribochemical reaction lead to the lower friction coefficients. When coupled with Si3N4 and SiC balls, the wear rates are relatively low due to the formation of friction films containing SiOx.

Characterization of dry-sliding wear phenomena in a novel martensitic structure based low-carbon Nb and V alloyed steel

The current study investigated unlubricated dry-sliding wear behaviour of a low-carbon Nb+V stabilized microalloyed steel in various treated states, i.e., as-received, direct-quenched (DQ, martensitic-structure) and tempered (T500) samples. The effects of applied normal load on specific wear-rate, worn-surface and sub-surface characteristics have been discussed, enlightening relevant deformation mechanisms. The specific wear-rate is found to be the lowest (2.91 ×10−5 mm3m−1N−1) for the DQ specimen, primarily due to its better combination of hardness, strength, and toughness. SEM investigation of worn-surfaces confirmed that abrasion (i.e., micro-cutting and ploughing) and oxidative wear mechanisms are the dominant phenomena in all the samples, while the counter-face material remained unchanged. The sub-surface analysis indicates the severely deformed region and bending of martensite is only 1–2 µm and 7 µm for the DQ sample, whereas increases to 3–5 µm and 15 µm, respectively, in the T500 specimen.

Effect of Counterface Material on Dry Sliding Wear of PEEK–PTFE Composites

Effect of Counterface Material on Dry Sliding Wear of PEEK–PTFE Composites

Nanohybrid of h‐BN nanosheets supporting CeO2 enhanced epoxy composite coatings with excellent self‐lubricating performance

AbstractPolymer self‐lubricating composite coatings have been widely used on the surface of machinery to extend the life of the moving systems/parts by controlling friction and wear. In this work, epoxy nanocomposite coating with the thickness of about 60 μm was fabricated with addition of hexagonal boron nitride nanosheets (BNNSs)/CeO2 nanohybrid for enhancement in antifriction and wear resistance. The active BNNSs were first obtained by exfoliating h‐BN with alkaline solution, and then the rare earth oxide of CeO2 nanoparticles were immobilized on the surface of BNNSs through hydrothermal method. The microstructure morphology and chemical composition of as‐proposed BNNSs/CeO2 were characterized by field emission scanning electron microscopy, HRTEM, Fourier transform infrared spectroscopy, RS, X‐ray diffraction, and X‐ray photoelectron spectroscopy. And the tribological behaviors of epoxy nanocomposite coatings containing BNNSs, CeO2, and BNNSs/CeO2 were investigated comparatively using ball‐on disc friction tester (MPX‐3). And the 440C stainless‐steel ball with diameter of 8 mm was used as the counterface material. Tribological tests showed that epoxy‐BNNSs/CeO2 had the best friction and wear reduction properties, and the lowest coefficient of friction and wear rate of epoxy‐based composite coating were achieved when the content of BNNSs/CeO2 was 0.5 wt%, with 84.9% and 96.3% reduction, respectively. Moreover, the effect of sliding conditions on the tribological performance of epoxy‐BNNSs/CeO2 was investigated. The corresponding enhancing mechanisms of BNNSs/CeO2 were discussed as well.

Role of the Matrix and Counterface Material in the Formation of Antifriction Characteristics of PI/PTFE and PEI/PTFE Composites

Role of the Matrix and Counterface Material in the Formation of Antifriction Characteristics of PI/PTFE and PEI/PTFE Composites

High temperature tribological properties of the D-gun WC-12Co coating in fluoride molten salt

Development of anti-corrosion and wear-resistant materials in FLiNaK molten salt is vital to the service safety and reliability of the various mechanical systems for the molten salt reactor. In this work, a WC-12Co coating was fabricated by detonation gun spraying technique. Its microstructure, mechanical properties and tribological behaviors in FLiNaK molten salt were studied. A ball-on-disk rotary configuration was selected for the tribological test, in which the WC-12Co coating disks slid against Al2O3, SiC, Si3N4 and steel counterface materials in FLiNaK molten salt and low-oxygen environment at 600 °C. The results showed that the WC-12Co coating displays a low porosity of 0.71%, a bonding strength of above 44 MPa and good anti-corrosion in molten salt. FLiNaK molten salt provides the good lubricity and inhibits the oxidation wear of the WC-12Co coating, contributing to the low friction coefficient of 0.097–0.17 and wear rate of (4.95–8.40) × 10−7 mm3N−1m−1.

Investigation of the Wear Behavior of AA6063/Zirconium Oxide Nanocomposites Using Hybrid Machine Learning Algorithms

This research created hot-pressed composites of the AA6063 matrix with varying concentrations of ZrO2 (0.25, 0.5, and 1 wt %). At sliding speeds of 80, 120, and 150 mm/s, the wear performance of the specimen was studied at loads of 10 N, 15 N, 20 N, and 25 N. The authors analyzed the counter-face material, the wear debris, and the worn surfaces to learn about the wear mechanisms. Developing these three machine learning (ML) algorithms was to evaluate the ability to predict wear behavior using the same small dataset collected using varying test processes. A thorough examination of each model hyperparameter tuning phase was performed. The predictive performance was analyzed using several statistical tools. The most effective decision-making algorithms for this data collection were those based on trees. Predictions made by the decision tree algorithm for the test and validation measurements have an accuracy of 86% and 99.7%, respectively. The best model was picked out based on the results of the predictions.

Scratch and Wear Behaviour of Co-Cr-Mo Alloy in Ringer’s Lactate Solution

Cobalt-chromium-molybdenum (Co-Cr-Mo) alloy is a material recommended for biomedical implants; however, to be suitable for this application, it should have good tribological properties, which are related to grain size. This paper investigates the tribological behaviour of a Co-Cr-Mo alloy produced using investment casting, together with electromagnetic stirring, to reduce its grain size. The samples were subjected to wear and scratch tests in simulated body fluid (Ringer's lactate solution). Since a reduction in grain size can influence the behaviour of the material, in terms of resistance and tribological response, four samples with different grain sizes were produced for use in our investigation of the behaviour of the alloy, in which we considered the friction coefficient, wear, and scratch resistance. The experiments were performed using a tribometer, with mean values for the friction coefficient, normal load, and tangential force acquired and recorded by the software. Spheres of Ti-6Al-4V and 316L steel were used as counterface materials. In addition, to elucidate the influence of grain size on the mechanical properties of the alloy, observations were conducted via scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD). The results showed changes in the structure, with a reduction in grain size from 5.51 to 0.79 mm. Using both spheres, the best results for the friction coefficient and wear volume corresponded to the sample with the smallest grain size of 0.79 mm. The friction coefficients obtained were 0.37 and 0.45, using the Ti-6Al-4V and 316L spheres, respectively. These results confirm that the best surface finish for Co-Cr-Mo alloy used as a biomedical implant is one with a smaller grain size, since this results in a lower friction coefficient and low wear.

Effect of the countermaterial on the tribological behavior of Cu45Zr46Al7Nb2 bulk metallic glass

Bulk Metallic glasses (BMGs) are produced through an extremely fast cooling process of a liquid metallic alloy (with a specific composition), so that the final solid state material is deprived of crystalline structure. The resulting mechanical properties of BMGs are of great interest for number of applications, including tribological applications. Recent studies highlighted a probable dependence of the friction and wear of BMGs on the counterface material. The present study investigates the relationship between the tribological behavior of Cu45Zr46Al7Nb2 BMG plates and six different countermaterials under linear reciprocating sliding. The selected countermaterials are: AISI 52100 and AISI 440C steels, brass and bronze, Cu45Zr46Al7Nb2 and Zr60Cu28Al12 BMGs. Results confirm that friction and wear are strongly correlated with the creation of a third body in the contact, whose nature (composition and morphology) depends on the countermaterial. Material transfer occurs either from the counterpart to the BMG or vice-versa, and the phenomenon is rather driven by the chemical affinities between the oxides formed than by the hardness and class of countermaterials (i.e. steels, Cu-based alloys, and BMGs). BMG/Brass contact indeed exhibits the lowest friction and the lowest wear while friction of BMG/bronze is two-fold higher and wear is among the highest of all the contact configurations tested.

High temperature tribological properties of D-gun Al2O3 coatings in fluoride molten salts

Anti-corrosion and wear-resistance coating is important to the reliability of the mechanical systems served in molten salt media. In this work, the Al2O3 coating was prepared on the stainless steel surface by a detonation gun (D-gun) spraying technique and its high temperature tribological properties in FLiNaK molten salt were studied systematically by sliding it against SiC, Al2O3 and steel materials. The results indicated that the Al2O3 coating has a high bonding strength of above 50 MPa with a porosity of 0.8 %. The tribological properties of the Al2O3 coating is significantly influenced by the counterface materials. The friction coefficients are between 0.14 and 0.45, and the wear rate increases from 2.2 × 10−5 mm3/N·m to 19.1 × 10−5 mm3/N·m by sliding it against SiC, Al2O3 and steel materials. The worn surface morphologies and compositions were specifically studied and correlated to these distinct behaviors.

Sliding wear of MAX phase composites Ti3SiC2–TiC and Ti3AlC2–Ti2AlC at 400 °C and the influence of counterface material (steel, Al2O3, and Si3N4) on wear behaviour

This study explores the feasibility of employing MAX phase composite as impregnated solid lubricants and/or as bulk material for advanced high temperature tribological applications. The development of microstructure of Ti-based MAX phase composites Ti3SiC2–TiC and Ti3AlC2–Ti2AlC fabricated by spark plasma sintering and their dry sliding tribological properties against bearing steel, Si3N4, and Al2O3 counterfaces were investigated using a ball on disc tribometer at 400 °C. An orientation relationship between the Ti3SiC2 matrix and TiC particle was established wherein Ti3SiC2/TiC interphase is a coherent boundary from which Ti3SiC2 grows epitaxially from TiC. Against steel, the MAX phase composites – in stark contrast to Si3N4 and Al2O3 – exhibited a negative wear behaviour due to the excessive wear and subsequent sintering of the transferred Fe particles at the sliding interface. Intrinsic lubrication mechanisms involving tribo-oxidation, tribochemical reaction, and mechanochemical reaction played a vital role in the friction and wear properties. The friction and wear properties of the Ti3AlC2–Ti2AlC MAX phase composite was superior to the Ti3SiC2–TiC composite owing to better oxidation kinetics governing the oxide growth and their retention. Evidently, the wear of the MAX phase is expected to proceed upon extensive deformation incorporating a range of microscale micromechanisms.

Influence of Counterface Materials on the Tribological Behavior of Dental Polymethyl Methacrylate Reinforced by Single-Walled Carbon Nanotubes (SWCNT)

Influence of Counterface Materials on the Tribological Behavior of Dental Polymethyl Methacrylate Reinforced by Single-Walled Carbon Nanotubes (SWCNT)

Role of Testing Conditions in Formation of Tribological Layers at Line Contacts of Antifriction CF-Reinforced PI- and PEI-Based Composites.

High-strength PI and PEI polymers differ by chemical structure and flexibility of the polymer chains that ensure lower cost and higher manufacturability of the latter. The choice of a particular polymer matrix is of actuality at design of antifriction composites on their basis. In this study, a comparative analysis of tribological behavior of PI and PEI- based composites was carried out with linear contact rubbing. The neat materials, as well as the two- and three-component composites reinforced with chopped carbon fibers, were investigated. The third components were typically used, but were different in nature (polymeric and crystalline) being solid lubricant fillers (PTFE, graphite and MoS2) with characteristic dimensions of several microns. The variable parameters were both load and sliding speed, as well as the counterface material. It was shown that an improvement of the tribological properties could be achieved by the tribological layer formation, which protected their wear track surfaces from the cutting and plowing effects of asperities on the surfaces of the metal and ceramic counterparts. The tribological layers were not formed in both neat polymers, while disperse hardening by fractured CF was responsible for the tribological layer formation in both two- and three component PI- and PEI-based composites. The effect of polymer matrix in tribological behavior was mostly evident in two-component composites (PI/CF, PEI/CF) over the entire P⋅V product range, while extra loading with Gr and MoS2 leveled the regularities of tribological layer formation, as well as the time variation in friction coefficients.

Prediction of wear performance of ZK60 / CeO2 composites using machine learning models

In this study, ZK60 magnesium matrix composites were produced with different content of CeO2 (0.25, 0.5 and 1 wt%) by hot pressing. The wear behaviour of the samples was investigated under loads of 5 N, 10 N, 20 N and 30 N, at sliding speeds of 75 mm/s, 110 mm/s and 145 mm/s. The worn surfaces, wear debris, and counterface material was analysed to reveal the wear mechanisms. Five machine learning algorithms were established to compare their prediction abilities of wear behaviour on a limited dataset measured under different test operations. The hyperparameter tuning phase of each model was conducted to provide a fair comparison. The prediction results were examined under various statistical measures. In the light of prediction results, the superior model was determined.

Tribological behaviour of PTFE composites: Interplay between reinforcement type and counterface material

In this paper, we studied the sliding wear behaviour of polytetrafluoroethylene (PTFE)-based composites under conditions relevant to rotary seals. We specifically aimed to investigate the interactions between different particle-based reinforcements (lamellar or spheroidal bronze particles, PEEK particles) and different counterfaces (uncoated or Cr2O3-coated stainless steel), building upon our own previous work on fibre reinforced-composites to make up for the paucity of literature papers on the role of counterfaces. Pin-on-disc tests were performed under different load and speed conditions using spherical-tipped composite pins against coated or uncoated stainless steel discs to mimic the (initially) non-conformal, unidirectional sliding contact of lip seals. Though all composites attained a steady-state regime controlled by a tribochemical wear mechanism, namely tribofilm formation, there were significant differences among the tribofilms produced by different tribo-systems. Systems that released fine, oxidized metal debris (bronze-filled PTFE and/or uncoated counterpart) developed >1 μm thick, continuous tribofilms on both mating surfaces. Thickness and continuity of the tribofilm decreased with a non-wearable Cr2O3-coated counterpart and/or PEEK as a filler. The tribofilm was conducive to lower steady-state friction, but not lower wear, against stainless steel, whereas all performances (friction coefficient, specific wear rate) were levelled out with a Cr2O3-coated counterface.