Tribological Behavior Research Articles

Enhanced tribological properties and cyto-biocompatibility of dental Ti6Al4V alloy via laser surface texturing

Currently, the application of titanium-based implants is hindered by challenges such as inadequate wear resistance and limited osseointegration. Surface texturing technique has been recognized as an effective strategy to improve the surface performances of metallic material. The present work adopts a nanosecond laser texturing technique to fabricate micro textures on the titanium substrate. Firstly, the influence of laser parameters on the texture morphology and quality were investigated. Subsequently, both isotropic and anisotropic surface textures were fabricated to examine the impacts of texture form on wettability, tribological behavior, and cell adhesion and proliferation. The obtained results reveal that both the two textures promote the surface wettability of Ti6Al4V alloy towards a hydrophobic direction. Furthermore, the anisotropic micro-groove texture and the isotropic micro-grid texture can reduce the wear rate of titanium alloy by 42.02% and 73.64%, respectively. However, from the perspective of cyto-biocompatibility, the anisotropic micro-groove texture is capable of triggering an excellent cell contact guidance phenomenon, leading to a dramatically accelerated proliferation rate and facilitating the bone tissue growth in a specific direction.

Investigation of tribological behavior for IN625 coating on IN738 superalloy by laser cladding process

Investigation of tribological behavior for IN625 coating on IN738 superalloy by laser cladding process

Effect of Surface Morphology and Internal Structure on the Tribological Behaviors of Snake Scales from Dinodon rufozonatum.

Snakes can move freely on land, in lakes, and in other environments. During movement, the scales are in long-term contact with the external environment, providing protection to the body. In this study, we evaluated the mechanical properties and scratching performance of the ventral and dorsal scales from Dinodon rufozonatum, a generalist species that moves on both land and in streams under wet and dry conditions. The results showed that the elastic modulus and hardness of the dry scales were greater than those of the wet scales. The average scale friction coefficient under wet conditions (0.1588) was 9.3% greater than that under dry conditions (0.1453). The scales exhibit brittle damage in dry environments, while in wet environments, ductile damage is observed. This adaptation mechanism allows the scales to protect the body by dissipating energy and reducing stress concentration, ensuring efficient locomotion and durability in both terrestrial and aquatic environments. Understanding how this biomaterial adapts to environmental changes can inspire the development of bionic materials.

An investigation on tribological behavior of TC bearing materials: Effect of nano-SiO2 concentrations under different loads in the drilling fluid environment

Both Nano-SiO2 (Silicon dioxide nanoparticles) additive concentration and axial load have profound effects on the friction and wear of Tungsten Carbide bearings in the drilling fluid environment. However, the coordinated role of them remains unknown. In this work, the effects of Nano-SiO2 concentrations and axial loads on the tribological behavior of bearing materials were investigated simultaneously. Results show that the water-based drilling fluid containing Nano-SiO2 exhibits more excellent lubrication properties under 200 N as compared with 70 N, and the optimal concentration of Nano-SiO2 additive is 1.0 wt% under all loads. High axial loads are conducive to improve the lubrication performance, and the lubrication mechanisms of Nano-SiO2 under different loads in water-based drilling fluid are the multitudinousness of synergistic effects, including rolling bearing, polishing, shielding, and self-healing effect, which all manifested there is an remarkable load dependence of Nano-SiO2 particles.

Quantitative characterization of rubber three-body abrasion wear: multi-scale testing and analysis methods based on defect detection

Abrasive wear is one of the main causes of rapid deterioration of rubber serviceability. Therefore, it is necessary to obtain information on the degree of rubber abrasion and the wear mechanism. Due to the complex nature of abrasive surfaces, obtaining accurate information on rubber abrasion is often difficult and provides limited quantitative parameters. This study presents a method to quantify rubber abrasion through defect detection and analysis. Accurate and fast identification of typical abrasion defects is achieved, and in addition, macro- and microscopic characterization data are provided based on the distribution of defects to understand the degree of abrasion and the wear mechanism. Experimental validation demonstrated the fast and accurate characterization capability of the method, especially the advanced advantages at the microscopic level. The method achieves accurate and efficient characterization of rubber abrasion, which helps to advance the study of rubber tribological behavior and is important for guiding engineering applications and improving design.

Effect of current on the tribological behavior of Cu-Fe-P immiscible alloy produced by laser powder bed fusion

Cu-based immiscible alloys have significant potential application value in the field of electrical contacts. This study investigated the tribological behavior of Cu-Fe-P immiscible alloys produced via laser powder bed fusion (LPBF) under current-carrying conditions. The alloys consist of softer ε-Cu phase and harder Fe-rich phases. The Fe-rich phase acts as a protective reinforcement during current-carrying friction and wear tests, improving the wear resistance of the alloy. With the increasing current, the coefficient of friction initially rose and then decreased, whereas the wear rate showed a gradual increase. At low currents (0, 2, 3 and 5 A), mechanical wear predominantly governs the wear mechanism. As the current increases, the mechanical wear gradually transitions from adhesive wear to abrasive wear, accompanied by weak oxidative wear. At higher currents (7 A and 10 A), the wear mechanism is dominated by arc erosion wear and oxidative wear. Notably, when the current exceeded 2 A, an oxide film consisting of CuO, Fe2O3, and Fe3O4 formed, enhancing the frictional properties of the alloy. Once the current surpassed 5 A, the arc discharge occurred at high currents, forming molten phases and arc erosion pits on the worn surface of the Cu-Fe-P immiscible alloy.

Evaluation, tribological examination, and multi‐objective optimization of aluminum‐fly ash‐egg shell composites for sustainability

AbstractThis study addresses the technological challenge of enhancing the mechanical and tribological properties of Al 6082 alloy by incorporating fly ash (FA) and eggshell (ES) as reinforcing materials. The objective is to fabricate hybrid metal matrix composites using sand casting, with varying weight percentages of eggshell and fly ash: 4 wt% eggshell with 6 wt% fly ash, 5 wt% eggshell with 5 wt% fly ash, and 6 wt% eggshell with 4 wt% fly ash. The experimental methodology involved designing experiments with response surface methodology (RSM), considering applied load, sliding velocity, and sliding distance as variables. The outcomes showed that the composite with 6 wt% eggshell and 4 wt% fly ash exhibited superior hardness, tensile strength, and impact resistance compared to pure Al 6082 and other composite variations. Additionally, this composite reduced the coefficient of friction (COF) from 0.489 for the base Al 6082 to 0.265. ANOVA based on RSM identified sliding distance as the most influential factor affecting COF. Optimal conditions for minimizing COF were determined to be a 40 N load, 0.215 m/s sliding velocity, and 800 m sliding distance through confirmatory trials. Scanning electron microscopy (SEM) analysis of the worn surfaces provided further insights into the wear mechanisms. The research reveals that integrating the addition of eggshell and fly ash significantly enhances the mechanical properties and reduces the friction of Al 6082, with sliding distance being a critical factor in tribological performance. This investigation is distinctive due to its innovative use of dual reinforcement with fly ash and eggshell, which are abundant, cost‐effective, and rarely employed together in this context. The research thoroughly investigates various reinforcement ratios, providing vital insights into how they affect the composite's properties, particularly in terms of improving tribological properties. Using RSM and ANOVA makes the findings more precise and reliable. The investigation highlights sliding distance as the key factor affecting the tribological behavior of the composites.

Tribological Behavior of Atmospheric Plasma-Sprayed Cu-Ni Coatings

Tribological Behavior of Atmospheric Plasma-Sprayed Cu-Ni Coatings

Composite Materials Used for Dental Fillings.

This article explores the properties of composite materials employed in dental fillings. A traditional nano-hybrid composite containing nanofiller particles exceeding 82% by weight served as a benchmark. The remaining samples were fabricated from ormocer resin, maintaining an identical nanofiller content of 84%. In all specimens, the nanoparticles were dispersed randomly within the matrix. This study presents findings from investigations into surface geometry, hardness, wettability, and tribological behavior. The microscopic observations revealed that ormocer-based samples exhibited greater surface roughness than those composed of the traditional composite. Hardness testing indicated that both ceramic addition and sample preparation significantly influenced mechanical properties. Ceramic-enhanced samples demonstrated superior hardness, surpassing the reference composite by 30% and 43%, respectively. Contact angle measurements revealed hydrophilic characteristics in the classic composite, contrasting with the hydrophobic nature of ceramic-containing samples. Tribological evaluations revealed the superiority of the classic composite in terms of friction coefficients and volumetric wear compared to ormocer-based materials.

Microstructural Analysis, Tribological, and Corrosion Behavior of Nix-Tiy Alloys Deposited Using µ-Plasma Additive Manufacturing Process

Microstructural Analysis, Tribological, and Corrosion Behavior of Nix-Tiy Alloys Deposited Using µ-Plasma Additive Manufacturing Process

Effects of chemical etching on surface structure and tribological behavior of silicate substrates

Abstract This study investigated the effect of chemical etching on the surface structure and tribological behavior of silicate substrates. Silicate surfaces were etched using a mixture of nitric acid (HNO3) and ammonium bifluoride (NH4HF2) for durations ranging from 1 to 60 min. The etched surfaces were characterized using optical microscopy, scanning electron microscopy, surface profilometry, water contact angle measurements, and UV–vis spectroscopy to evaluate the changes in surface morphology, roughness, wettability, and optical properties. Tribological performance was assessed using reciprocating ball-on-plate friction tests. The results showed that increasing the etching time resulted in the formation of microscale surface features, increased surface roughness, enhanced hydrophilicity, and reduced optical transmittance. The average friction coefficient decreased with an increase in the etching time up to 30 min, beyond which a slight increase was observed. The 1-minute etched specimen exhibited the best wear resistance with the narrowest wear track and the least material removal. The improved tribological performance was attributed to the formation of a stable transfer film, reduced real contact area, and entrapment of wear debris. This study highlights the potential of chemical etching as a technique to tailor the surface structure and tribological properties of silicate materials for various applications.

Processing and the Effect of Nb–Mo on the Microstructure, Mechanical and Tribological Behavior of High-Cr Cast Iron

Processing and the Effect of Nb–Mo on the Microstructure, Mechanical and Tribological Behavior of High-Cr Cast Iron

Tribological behavior and surface characteristics of severe surface plastic deformed as-cast and 3D-printed SS316L using LSP

The effect of laser shock peening (LSP) on as-cast and three-dimensional (3D)-printed SS316L alloys was studied. The LSP process was found more dominant than the 3D-printing technique over as-cast alloy steel for enhancing the properties. The process of laser shock peening results in microlevel changes in the structure of the material. This, in turn, leads to grain refinement and the increase of compressive residual stresses. After LSP treatment, the surface microhardness value increased by 33% in both as-cast and 3D-printed SS316L alloys with the hardness gradient from surface to subsurfaces. The wear rate of as-cast specimens and 3D-printed specimens were reduced to 1.28 10−6 and 1.14 10−6 g/m, respectively, and tensile value increased up to 22% after LSP treatment. The scanning electron microscopy images on the wear track confirm the vulnerability of the untreated SS316L alloys with adhesion wear and surface delamination. This difference was because the wear rate of the 3D-printed specimens was lesser than the as-cast SS316L alloys due to their layer-by-layer high-temperature finishing. The samples were characterized by optical microstructure to identify the surface refinement, and confirmed by the transmission electron microscope images along with specified area electron diffraction pattern for the accumulation of dislocation and grain refinement after LSP treatment. The accumulated residual stress was measured by X-ray diffraction technique and it found the highest compressive residual stress after LSP treatment was accrued by 3D-printed SS316L alloy with 310 MPa.

Studies on tribological behavior of aluminum hybrid composites strengthened with MoS2 and wheat husk ash

The current study examines the dry sliding wear characteristics of a hybrid aluminum matrix composite reinforced with wheat husk ash (WHA) and molybdenum disulfide (MoS2), produced through the squeeze casting technique. Experiments were conducted utilizing Taguchi's L27 (3)13 orthogonal array, with input parameters including applied load (20, 30, 40 N), sliding speed (1, 2, 3 m/s), reinforcement percentage (wt. 2.5, 5% and 7.5%), while wear and friction coefficient were observed as measurable responses. Analysis of variance (ANOVA) results highlighted that the reinforcement percentage had the most significant impact on the wear behavior of the hybrid composite. Notably, the (Al/5WHA/5MoS2) hybrid composite exhibited superior wear resistance (129 µm), accompanied by a 27% increase in hardness compared to the parent metal. Surface morphology analysis of worn-out specimens depicted the presence of fine grooves, delamination, and cracks.

Comparative Study on Tribological Behavior of Plasma-Sprayed YSZ Coatings Deposited with Different Powders

Comparative Study on Tribological Behavior of Plasma-Sprayed YSZ Coatings Deposited with Different Powders

Study on the sliding tribological behavior of ZIF-8 under lubricating grease conditions

ZIF-8 is widely applied in lubrication, adsorption, and catalysis owing to its unique physicochemical properties. Previous experimental studies have demonstrated its feasibility as a lubricant additive. In the present work, the lubricating performance of ZIF-8 as an additive to lithium-based grease is quantitatively and dynamically analyzed at the atomic scale using molecular dynamics simulations. Friction wear experiments are also conducted to elucidate the lubrication mechanism of ZIF-8. The simulation and experimental results indicate that the incorporation of ZIF-8 effectively enhances the antifriction and antiwear characteristics of lithium grease. The most significant improvement in the lubrication performance of the grease is obtained at a mass fraction of 2.0 wt. % ZIF-8, which reduces the friction factor μ of the grease by about 17.0% and the wear by ∼40.0%. Furthermore, the molecular dynamics simulations reveal that ZIF-8 primarily functions as a ball bearing under low-load conditions. However, under high-load conditions, ZIF-8 undergoes significant deformation and primarily acts as a filler. This explains the experimentally observed significant reduction in friction coefficient after the addition of ZIF-8. The results of this study provide a theoretical foundation for the development of new environmentally friendly grease additives.

Microstructural evolution and tribological behavior of HVAF sprayed FeCoNiCrMox (x=0, 0.2, 0.5, 1) coatings

High entropy alloy coatings with a unique microstructure and excellent mechanical properties show significant potential for development in friction-related applications. In this study, the microstructure, phases, hardness and tribological behavior of FeCoNiCrMox (x = 0, 0.2, 0.5, 1.0) coatings fabricated by HVAF spraying were investigated. The coating changes from a single FCC structure (x=0, 0.2) to a dual phase structure of FCC and σ (x=0.5, 1), accompanied by an expansion in the segregation regions of Cr and Mo elements. The hardness of coatings increased with higher Mo content. Tribology tests were carried out at room temperature using Si3N4 ceramic and GCr15 steel as counterfaces. The results demonstrate that, when paired with GCr15, the wear resistance of the coatings scale proportional with hardness. However, when paired with Si3N4, the coating wear rate exhibits an initial increase followed by a decrease. Notably, the FeCoNiCr and FeCoNiCrMo0.2 coatings exhibited milder friction and wear behavior when in contact with Si3N4 compared to GCr15 steel, attributed to the dominant oxidative wear. This study provides new insights and directions for the design of customized high-entropy alloy coatings based on specific friction conditions.

Investigation of Tribological Behavior of PTFE Composites Reinforced with Bronze Particles by Taguchi Method

Reinforced PTFE materials can be designed to show high mechanical stability against harder materials under sliding wear conditions. Especially bearing metal-reinforced PTFE is of high practical interest. In this class of materials, bronze-filled PTFE was reported to obtain high wear resistance, a low coefficient of friction (COF), and excellent self-lubrication properties in sliding conditions. In the statistical approach of this work, PTFE composites reinforced with 25 vol%, 40 vol%, and 60 vol% bronze particles were evaluated against pure PTFE regarding wear behavior under varied wear test parameters, i.e., material, normal load, and sliding speed. Wear tests were planned to use a standard orthogonal array based on the Taguchi design method. An analysis of variance test was utilized to quantify the effects of test parameters on the wear behavior of the bronze/PTFE composites and pure PTFE. According to the variance analysis, the material type has the largest influence on the COF and the specific wear rate (SWR) under test conditions of this work. Both COF and SWR were found to be influenced by the material type (29.83% and 96.16%), the normal load (33.34% and 0.95%), and sliding speed (9.14% and 1.28%). The lowest SWR and COF values were achieved at the optimum wear test conditions where the wear test parameters were 1 m/s sliding speed (A4B2C2) at PTFE + 60 vol.% bronze reinforced composite 50 N application load and 0.32 m/s sliding speed (A4B3C1) at PTFE + 60 vol.% bronze reinforced composite 100 N application load, respectively.

Synergic effects of physio‐mechanical performances on sliding‐rolling tribological and abrasion behaviors of polyisoprene based aviation tire treads

AbstractAbrasion and tribological properties of tread rubber play a crucial role in governing the service life of aviation tires and the safety of aircrafts. Polyisoprene (IR) with the same chemical structure as natural rubber shows great potential for application in aviation tires. Herein, the abrasion and tribological behaviors of IR based composites under sliding‐rolling conditions were investigated in relation to the carbon black (CB N234) content, sliding‐rolling ratio, ambient temperature, and counterparts in order to provide guidance for the development of high‐performance aviation tire treads. Moreover, the relationship between wear performances and physical–mechanical properties was discussed to establish a prediction model. The results revealed that physical and mechanical properties affected wear performances in a synergetic manner, which could be described as a negative linear correlation of the folding wear with the product of hardness and rebound resilience (H4R) and the ratio between rebound resilience and tensile strength ((1‐R)/σ) even at elevated temperature and sliding‐rolling ratio regardless of the counterpart. The increase in CB N234 content and sliding‐rolling (s‐r) ratio resulted in a transition of the wear mechanism from folding to abrasion due to the formation of soft rubber particles with a certain fluidity and a lubricating transfer film that was located at the friction interface and was generated by the thermal‐mechanical degradation of the IR matrix when it was rubbed against steel counterparts, which marred the aforementioned negative linear relationship.Highlights The increase in temperature improved the abrasion resistance of tire treads. The folding wear was negatively and linearly related to H4R and (1‐R)/σ. Increasing CB N234 content and s‐r ratio made a transition of wear mechanism.

Towards cleaner machining: Experimental investigation of collagen-in-water as a novel type of metalworking fluids – A technical feasibility study

Driven by environmental challenges, health concerns and increasing legislative restrictions, a high demand for research regarding alternative metalworking fluids (MWFs) to substitute the conventional mineral oil-containing fluids emerges. In recent years, bio-based fluids have continuously gained attention, as their usage could mitigate the disadvantages of conventionally used fluids, which usually contain mineral oil. Against this background, this research aims to contributing towards biological MWFs by investigating the technical applicability of collagen-in-water fluids through evaluations and comparisons with MWFs. The analyzed bio-based MWF is based on collagen-hydrolysate powder dissolved in water, with collagen acting as a viscosity-increasing additive. The prepared fluids were investigated regarding their viscosity and tribological behavior in cylinder-on-ring experiments as well as tapping-torque tests. Afterwards, first machining experiments were performed for honing and grinding of hardened steel. Force-led cylinder-on-ring experiments show a significant wear reduction, e.g. a value of 13.4 mm2 at 3 wt.% collagen compared to 33.0 mm2 with pure distilled water. Wear further decreased with increasing collagen content. At 3 wt.% and again compared to pure water, tapping torque was reduced by 29 % to 181.7 N·cm, no further torque reduction was observed with increasing collagen concentration. In honing, roughness was reduced using collagen-in-water, however, an 8 wt.% collagen fluid resulted in an 18 % reduction in material removal rate compared to honing oil. In internal grinding, an 8 wt.% collagen fluid achieved an Ra of approximately 0.8 μm, compared to around 0.55 μm with emulsion. The application results demonstrate a high potential for collagen-in-water fluids, however, adjustments are necessary for obtaining competitive fluids.