Erosive Wear Research Articles

Hematological Response to Particle Debris Generated During Wear–Corrosion Processes of CoCr Surfaces Modified with Graphene Oxide and Hyaluronic Acid for Joint Prostheses

Various surface modifications to increase the lifespan of cobalt–chromium (CoCr) joint prostheses are being studied to reduce the wear rate in bone joint applications. One recently proposed modification involves depositing graphene oxide functionalized with hyaluronic acid (a compound present in joints) on CoCr surfaces, which can act as a solid lubricant. This paper analyzes the biological alterations caused by wear–corrosion phenomena that occur in joints, both from the perspective of the worn surface (in vitro model) and the particles generated during the wear processes (in vivo model). The analysis of the inflammatory response of macrophage was performed on CoCr surfaces modified with graphene oxide and functionalized with hyaluronic acid (CoCr-GO-HA), before and after wear–corrosion processes. The wear particles released during the wear–corrosion tests of the CoCr-GO-HA/CoCr ball pair immersed in 3 g/L hyaluronic acid were intra-articularly injected into the experimental animals. The hematological analysis in vivo was made considering a murine model of intra-articular injection into the left knee in male adult Wistar rats, at increasing concentrations of the collected wear particles dispersed in 0.9% NaCl. Non-significant differences in the inflammatory response to unworn CoCr-GO-HA surfaces and control (polystyrene) were obtained. The wear–corrosion of the CoCr-GO-HA disk increased the inflammatory response at both 72 and 96 h of material exposure compared to the unworn CoCr-GO-HA surfaces, although the differences were not statistically significant. The pro-inflammatory response of the macrophages was reduced on the worn surfaces of the CoCr modified and functionalized with graphene oxide (GO) and hyaluronic acid (HA), compared to the worn surfaces of the unmodified CoCr. The hematological analysis and tissue reactions after intra-articular injection did not reveal pathological damage, with average hematological values recorded, although slight reductions in creatinine and protein within non-pathological ranges were found. Some traces of biomaterial particles in the knee at the highest concentration of injected particles were only found but without inflammatory signs. The results show the potential benefits of using graphene in intra-articular prostheses, which could improve the quality of life for numerous patients.

Effect of Electrofriction Treatment on Microstructure, Corrosion Resistance and Wear Resistance of Cladding Coatings

In recent years, the issue of increasing the wear resistance of the working bodies of agricultural machinery designed for cutting and breaking the soil has received special attention. The surface layers of working bodies of agricultural machinery during operation are subjected to intensive abrasive wear, which leads to rapid wear of equipment and a reduction in its service life. The induction cladding method using materials such as Sormait-1 is widely used to increase the wear resistance of tool working surfaces. However, after coating, additional heat treatment is required to improve the physical and mechanical properties of the material and increase its durability. In electrofriction technology (EFT) hardening, the surfaces of the parts are subjected to melting under the influence of electric arcs. In this work, three types of surface treatment of L53 steel have been investigated: induction cladding using Sormait-1, electrofriction treatment, and a combination of induction cladding followed by electrofriction treatment. The microstructure was analyzed using optical microscopy and scanning electron microscopy. Erosion and abrasion tests were carried out in accordance with ASTM G65 and ASTM G76-04 international standards to evaluate the wear resistance of the materials under mechanical stress. A dendritic structure was formed after the induction cladding of the Sormait-1 material, but subsequent electrofriction treatment resulted in a reduction of this dendritic structure, which contributed to an increase in the hardness of the material. However, the highest hardness, reaching 965 HV, was recorded after electrofriction treatment of L53 steel. This is explained by needle martensite in the structure, which is formed as a result of quenching. Further, the influence of structural characteristics and hardness on erosion and abrasion wear resistance was examined. The analysis showed that the material microstructure and hardness have a decisive influence on the improvement of wear resistance, especially under conditions of intensive erosion and abrasive friction.

Nanocrystalline NiTiB reinforced aluminum matrix composites: Synthesis, structural, mechanical and corrosion properties

In this study, aluminum composites were developed using a powder metallurgy route by incorporating varying amounts of nanocrystalline NiTiB into the Al2024 alloy. The effects of nanocrystalline NiTiB on the structural, morphological, corrosion, and mechanical properties of the aluminum composites were thoroughly investigated. The results showed that the base alloy and composites with 2% and 4% NiTiB exhibited the highest relative density. The composite with 4% NiTiB achieved the maximum hardness of 87.4 HV. Additionally, the inclusion of nanocrystalline NiTiB significantly improved the compressive strength, corrosion resistance, and wear resistance of the composites. Specifically, the compressive strength increased by approximately 2% with 2% NiTiB and by around 13% with 12% NiTiB. Corrosion resistance was highest in the composite with 4% NiTiB, as confirmed by electrochemical impedance spectroscopy. In the wear-loss study, the wear loss of the composites was found to be reduced by 244% and 457% for those reinforced with 2% and 12% NiTiB, respectively. These findings underscore the potential of nanocrystalline NiTiB to enhance the performance of Al2024 composites in applications demanding superior corrosion resistance, mechanical strength, and wear resistance.

Microstructural, mechanical and wear behaviour of AA7075/ZrSiO4 surface composite developed via multi pass friction stir processing

ABSTRACT The microstructural, mechanical, and wear behaviour of the ZrSiO4-reinforced AA7075 surface composites fabricated through friction stir processing was analysed. The microstructure of the friction stir processed surface composite shows refined grain 52 μm, 20 μm and 5 μm after 1, 2 and 3 FSP pass which also leads to the uniform dispersion of reinforced ZrSiO4 particles in the A7075 surface as revealed by SEM, EDS, and XRD. The microhardness and tensile strength of the FSP surface composite were significantly improved by 35% and 54%, respectively, with the effect of ZrSiO4 particles, after six passes as compared to the substrate material. The slurry abrasive wear resistance of the surface composite after six FSP passes increased to 95% as compared to the A7075 substrate material. Similarly, the slurry erosive wear resistance was improved with increasing slurry rotating speed, but as slurry concentration increased at six passes, the wear rate decreased further due to self-colloids occurring between the slurry particles. Hence, slurry erosive wear resistance was increased by up to 220% as compared to substrate material. Hence, the novel fabrication of friction stir processed surface composite will be very beneficial for aerospace and marine structural components and the fabrication process is very robust and cost-efficient.

A Pilot Investigation Into the Use of Teledentistry and Artificial Intelligence to Assess Dental Erosion in Competitive Swimmers.

The aim of the study was to assess the prevalence of dental erosion in competitive swimmers using teledentistry and artificial intelligence. An opportunistic sample of 20 competitive swimmers was recruited. The participants reported that they carried out an average of 2.40 h of training per day, 4.45 days per week. Data gathering was carried out remotely. The subjects completed a digital questionnaire and uploaded three photos of their mouth. Intraoral photographs were analyzed using the "Intact-Tooth" application to assess dental erosion. A statistical analysis was carried out to verify a possible correlation between the collected data. The average calculated Basic Erosive Wear Examination (BEWE) index was 13.95, and 11 subjects (55%) had a severe BEWE (≥ 14). More than 40% of the participants disagreed about having social issues related to tooth hypersensitivity. Considering only subjects with a severe total BEWE value, we have observed an indirect correlation between the degree of dental erosion and diet (Pearson coefficient r = -0.57), whereas a direct correlation was observed between dental erosion and age (r = 0.493) and between BEWE and weekly training hours (r = 0.217). Because of their lifestyle, competitive swimmers can be considered at a higher risk of developing dental erosion. In this context, teledentistry and AI tools can be effectively used to intercept those at the highest risk and prevent the occurrence of conditions. Dental erosion assessment in competitive swimmers using teledentistry and AI.

Corrosion resistance and wear behavior of CoCrFeNiMn@Gr high entropy alloy-based composite coatings prepared by laser cladding

In this study, we utilize laser cladding to apply a CoCrFeNiMn HEA with 2 wt.% few-layer graphene (Gr) coating onto the surface of Q235B mild steel. Alcohol stirring method was used for HEA and Gr preparation of composite powder. Raman spectroscopy and energy dispersion spectroscope (EDS) indicate the successful mixing of HEA and Gr powders, with Gr adhering to the surface of the HEA powder in a lamellar structure. The X-ray diffraction (XRD), scanning electron microscope (SEM), EDS, and Electron backscatter diffraction (EBSD) analyses revealed that grain refinement and the formation of fine carbide-hard phases in the HEA/Gr coating improve microhardness and wear resistance. The average Schmidt factors of the coating decreased from 0.47 to 0.45 with the addition of Gr, indicating enhanced resistance to plastic deformation and anisotropy. Nanoindentation experiments demonstrated that the HEA/Gr coatings exhibit superior resistance to plastic deformation, effectively enhancing the coating’s durability against spalling under stress and wear conditions. The microhardness of the HEA/Gr coating increased by 99.25%, and the wear rate decreased by 86.31% compared to the HEA coating alone. The open circuit potential (OCP), linear polarization curve, Tafel curves, electrochemical impedance spectroscopy (EIS), and Mott-Schottky tests all indicated that the HEA/Gr coating possesses superior corrosion resistance. X-ray Photoelectron Spectroscopy (XPS) results suggest that the passivation film of the HEA/Gr coating, which contains more oxides and less hydroxide, is more protective and denser, thereby slowing the corrosion rate.

Digital Approach Provides Predictability in Increasing the VDO in Erosive Wear: Clinical Technique and 9-Year Follow-Up.

This clinical case describes a digital workflow using face scans and CAD/CAM technology for a full-mouth rehabilitation with increased vertical dimension of occlusion (VDO) with adhesive lithium disilicate restorations after 9 years. A healthy, 46-year-old man displaying severe tooth wear, underwent an extensive full-mouth rehabilitation involving an increase of the VDO through laminate veneers and adhesive partial coverage lithium disilicate restorations. Anatomical landmarks of the face and reference planes were captured using a digital face scanning system. The anatomical position of the maxilla was registered with a transfer device. Digital data sets of the intraoral situation combined with a facial scan enabled precise virtual planning, guiding minimally invasive preparations. Long-term provisional restorations, milled from high-performance polycarbonate, were used to test the novel VDO before the final lithium disilicate restorations were fabricated. This approach provided a time- and cost-efficient treatment solution. No failures were observed at the 9-year follow-up. Utilizing face scans and design software enable a virtual visualization and comprehensive quality control for patients with dental wear, resulting in significant time savings and increased predictability for the dental technician, dentist and patient. The described digital workflow optimizes the planning and implementation of a comprehensive adhesive full-arch rehabilitation with an increase of the VDO. The clinical long-term follow up result of CAD/CAM assisted minimally invasive lithium disilicate restorations after 9 years demonstrates to clinicians a reliable treatment concept for patients with dental wear.

Corrosion and wear performance and mechanism study of ZrB2/AA6016

Abstract This study involved the fabrication of aluminum matrix composites reinforced with ZrB2/AA6016 particles using the KBF4-Al-K2ZrF6 reaction system， the composites were then subjected to T6 heat treatment. An investigation was conducted to examine the impact of varying friction speeds on the corrosion and wear characteristics of ZrB2/AA6016. An investigation was conducted to study the frictional wear behavior of ZrB2/AA6016 in the presence of 3.5wt. % NaCl, both before and after T6 heat treatment. The study also aimed to understand the underlying mechanism of this behavior. The results indicate that the T6 heat treatment mitigates the impact of thermal stresses and strains caused by thermal mismatch, hence enhancing the material's wear resistance. The coefficient of friction (COF) for heat-treated ZrB2/AA6016 is lower than that for unheated-treated ZrB2/AA6016. As friction increases, the pace at which the material wears down tends to decrease. At a friction wear velocity of 50 mm/s, the wear rate of the material is minimized both before and after heat treatment, measuring 0.23×10-2mm3/Nm and 0.22×10-2mm3/Nm, respectively. Through the utilization of XRD, SEM, EBSD, TEM, and XPS analytical techniques, it has been determined that the ZrB2 particles exhibit strong bonding with the Al matrix. Additionally, the particle diameters range from 50~150nm. Following the T6 heat treatment, the grain size measured 40.53μm, while the proportion of large-angle grain boundaries was found to be 66.4%. The accumulation of Cl- resulted in the formation of localized corrosion pits on the surface undergoing wear, hence hastening the deterioration of the material. The primary causes of wear failure are corrosive wear, abrasive wear, and oxidative wear.

Failure mechanisms and influencing factors on orthopaedic knee implant failure – A comprehensive review

Background Total knee replacement (TKR) is an effective orthopaedic surgical procedure to confront osteoarthritis and restore bone joint mobility, relieve pain, and enhance the quality of life. The improvements in implant design and the use of high-wear resistance polyethylene bearings improve the survival of implants. Despite the advancements, the implants still failed and required revision surgery. Also, with an increase in the trend of young patients getting knee replacements, there is a possibility of a higher revision rate. Thus, understanding the failure cause, failure mechanisms and the influencing factors is pertinent. Methods A systematic review of the available literature was performed for different modes of failure. All the observations are collated and found the more predominant failure modes. Also, the data pertaining to the failure mechanisms, and the influencing factors of the failure mechanisms are collected from various literature and provided comprehensively. Results Infection (30%) becomes the primary cause of implant failure followed by loosening (20%) and instability (18%). The types of wear on knee implants are polyethylene wear, backside wear, impingement wear, and corrosive wear. The factors influencing these wear are material processing, shelf age, implant design, surface topography, and activity level. Conclusions Moderately cross-linked, and sequentially processed polyethylene has better wear resistance. Less conformal contact with minimum shelf age provides less wear at articulation and backside. A polished tibial tray with a sophisticated locking mechanism reduces the backside wear of PE, and proper design consideration could reduce impingement wear.

Hydroxyapatite in oral care products: in vitro effects on erosion/abrasion and analysis of formulation components.

Hydroxyapatite (HAP) is promoted as biomimetic material in dentistry. The aim of the study was to investigate whether HAP-containing formulations can reduce erosive/abrasive tissue loss and to analyse components in these formulations. Two HAP toothpastes with and two without fluoride and a HAP mouthrinse were investigated, controls were active-agent-free toothpaste, SnF2 toothpaste and F/Sn mouthrinse. For 10 d, human enamel samples were eroded for 2 min, 6x/d in 0.5% citric acid and immersed for 2 min, 2x/d in toothpaste slurries or mouthrinse. Half were additionally brushed for 15s, 2x/d. The particulate fraction was extracted and examined morphologically and with element analyses. Other parameters were REA, RDA, fluoride and calcium content. The F/Sn mouthrinse almost completely prevented tissue loss; none of the HAP formulations reduced tissue loss compared to the negative control, two increased it instead. Brushing increased tissue loss in all groups except the F/Sn mouthrinse. All toothpastes contained amorphous particles of different sizes. Elemental analysis identified Si and O, additionally Ca and P were present in small amounts on the particles of the HAP toothpastes and one HAP+F toothpaste. In the liquid phase, elevated calcium levels were found in one HAP toothpaste and in both HAP+F toothpastes; in the formulation with the highest value, the fluoride concentration was low. REA and RDA values were not associated with tissue loss. Whether alone or in combination with fluoride, HAP formulations had either no or a detrimental effect on erosive tissue loss and could not reduce abrasion. In the context of erosive tooth wear, HAP seems to be neither an alternative to fluoride nor a suitable supplement to it.

Abrasive Wear Characteristics of 30MnB5 Steel for High-Speed Plough Tip of Agricultural Machinery in Southern Xinjiang Region

The high-speed plough tip is the core soil-touching component in southern Xinjiang field cultivation, but the interaction of the plough tip with the soil results in severe wear of the tip. The friction behaviour of sand and soil on plough tips was investigated with a homemade rotary abrasive wear tester in a one-factor multilevel test with three parameters: moisture content, velocity/rotational speed and friction distance. The objective was to study the friction behaviour of the sand soil and plough tip and analyse and characterise the wear amount, wear thickness and compressive stress distribution, three-dimensional wear morphology and microscopic wear morphology of the plough tips. The results show that with increasing speed, the wear amount changes more gently; with increasing soil water content, the soil adhesion force and lubricating water film increase so that the wear amount follows a second-order parabolic law; and with increasing friction distance, the wear amount gradually increases, and the wear rate also shows an upward trend when the plough tip is in the abrasive wear stage. The tip makes contact with the firmer soil with higher surface compressive stresses, causing the most wear. As the friction distance increases, sand particles become embedded in the contact surfaces, creating a groove effect along with spalling pits caused by fatigue wear. During the whole wear period, the groove effect is always accompanied by spalling pits appearing repeatedly. The analysis of the wear micromorphology of the plough tip shows that the number of flaking pits gradually decreases in the direction of soil movement, and the form of damage changes from impact wear to plough groove scratches. Abrasive wear interacts with corrosive wear to exacerbate plough tip wear.

Analysis of erosion and sealing characteristics of V-regulating ball valves for coal chemical industry

Purpose This study aims to research the erosion wear characteristics and sealing performance of V-regulating ball valve in coal chemical process pipelines, which provides a theoretical reference for improving its antiwear and sealing performance. Design/methodology/approach Taking the V-regulating ball valve as the research object, based on the computational fluid dynamics and the theory of erosion wear, the authors studied its erosion characteristics under different medium parameters and analyzed the sealing performance under the heat-fluid–solid coupling working condition. Findings The erosion wear mechanism of the valve sealing surface is the simultaneous action of cutting and deformation. When the medium flow velocity, particle mass flow rate and particle size increase, the maximum erosion rate and average erosion rate in the V-regulating valve increase. The inner diameter Mises contact stress of the sealing surface is symmetrically distributed in a “wing shape,” and the contact stress of the outer diameter is distributed in a “butterfly shape.” Due to the superposition of thermal stress and pressure stress in the contact transition zone to produce a significant stress concentration. Practical implications The findings will provide a theoretical basis for improving the erosion resistance and sealing performance of V-regulating ball valve in coal chemical industry. Social implications V-type regulating ball valve is widely favored by coal chemical enterprises and petrochemical enterprises because of its wide adjustment ratio and good erosion resistance. Originality/value The V-regulating ball valve wear mechanism for cutting and deformation simultaneously, and its wear rate is positively correlated with the medium flow rate, particle mass flow rate and particle size. After the valve is opened, there is a significant stress concentration occurs in the contact transition zone due to the superposition of thermal stress and compressive stress. The findings will provide a theoretical basis for improving the erosion resistance and sealing performance of V-regulating ball valve in coal chemical industry. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2024-0205/

An investigation on the mechanical, thermal and tribological properties of newly developed polyester composites made with Pistachio shell particles for industrial applications

The drive for sustainability and addressing environmental concerns has led to the productive use of bio-waste. This research investigates the potential of pistachio (Pistacia vera) nut shell particles as a novel filler in polyester composites. The study explores the use of these nut shells as a reinforcing material in polyester-based composites to evaluate their mechanical and thermal properties. Pistachio shell particles (PSP) are mixed with polyester resin in varying weight fractions (0%, 1%, 3%, and 5%) to create a new type of composite. The impact of filler content, impingement angle and striking velocity on the erosive wear behavior of these composites are also studied. The mechanical results for the composites revealed that incorporating PSP filler resulted in the maximum rise in tensile (96.61%), impact strength (66.66%), micro-hardness (52.94%), under loading of 5 wt% of PSP filler. However, the composite with 3 wt% of PSP filler, resulted in the maximum rise of flexural strength (135.65%) and flexural modulus (45.28%). Results showed that, composites with 5 wt% of PSP filler exhibited superior erosive resistance. An optimal parameter setting is determined for minimum erosion rate and subsequently validated by conducting confirmation experiment as per Taguchi methodology. Different modes of material removal, wear craters and other qualitative attributes are examined by a scanning electron microscopy during erosion experiment of the samples. Thus, the utilization of agro/food wastes in the development of bio-based products holds significant potential and offers the possibility of replacing conventional materials in various industrial applications.

Study on corrosion behavior and first-principle analysis of M50 steel in lubricating oil contaminated by salt water

The corrosive wear of M50 steel in lubricating oil contaminated with saline is a form of wear that often occurs within the main shaft bearings of aviation engines carried by aircraft working at sea. In the present paper, the corrosion behavior of M50 steel in lubricating oil contaminated with saline was studied. The open-circuit potential, polarization curve and impedance spectrum were analyzed by rotating electrochemical corrosion wear test. A three-layer interface microscopic molecular model was established with Materials Studio to simulate the dynamic corrosion evolution process of M50 steel self-matching pairs and the adsorption energy was calculated. The results show that the corrosion type is pitting corrosion. With the increase of saline concentration, the corrosion area becomes wider and shallower, and the size of the pitting core gradually decreases. The weight loss of M50 steel increases over time, but the trend slows down, which is also shown in the MS simulation results. Electrochemical tests show that the tribocorrosion of M50 steel is related to load, speed. As the load increases, the corrosion rate decreases. And, as the speed increases, the corrosion rate increases. This has practical significance for extending the understanding of tribocorrosion of M50 steel in marine atmospheric environments.

Investigation of Friction and Erosion Wear Properties of Titanium and Titanium Alloy Pipes.

Titanium alloys are applied in oil and gas development and transportation to improve conditions because of their high specific strength and corrosion resistance. However, the disadvantage of poor wear resistance has become an obstacle to developing titanium alloys. The friction and wear properties of pure titanium TA3 and titanium alloy TA10 were tested under different loads and different friction forms using a reciprocating friction and wear tester. Moreover, the erosion resistance of pure titanium TA3 and titanium alloy TA10 was studied using a gas-solid erosion tester. The results show that the wear rate of TA3 and titanium alloy TA10 increases with increasing friction load. Under a load of 50 N, the mass losses of TA3 under dry friction and wet friction were 0.0013 g and 0.0045 g, respectively, while the mass losses of TA10 were 0.0033 g and 0.0046 g, respectively. While the load increased to 70 N, the mass loss of TA3 was even greater, reaching 0.0065 g, and the mass loss of TA10 was 0.0058 g. The wear forms of TA3 and TA10 include abrasive wear, adhesive wear and oxidation wear. The joint action of various friction forms leads to the loss of materials. Under the simulated working conditions, the erosion rates of TA3 and TA10 were 1.01 × 10-3 g/s and 0.94 × 10-3 g/s. The erosion mechanism is the same, including plowing, indentation and cracking.

Erosion Wear Behavior of HVAF-Sprayed WC/Cr3C2-Based Cermet and Martensitic Stainless Steel Coatings on AlSi7Mg0.3 Alloy: A Comparative Study

The paper presents a comparative study of the erosion wear resistance of WC-10Co4Cr, Cr3C2-25NiCr and martensitic stainless steel (SS) coatings deposited onto an AlSi7Mg0.3 (Al) alloy substrate by high-velocity air‒fuel (HVAF) spraying. The influence of the abrasive type (quartz sand or granite gravel), erodent attack angle, thickness, and microhardness of the coatings on their and Al substrate’s wear resistance was comprehensively investigated under dry erosion conditions typical for fan blades. The HVAF-spraying process did not affect the Al substrate’s structure, except for when the near-surface layer was 20‒40 μm thick. This was attributed to the formation of a modified Al-Si eutectic with enhanced microhardness and strength in the near-substrate area. Mechanical characterization revealed significantly higher microhardness values for the cermet WC-10Co4Cr (~12 GPa) and Cr3C2-25NiCr (~9 GPa) coatings, while for the SS coating, the value was ~5.7 GPa. Erosion wear tests established that while Cr3C2-25NiCr and SS coatings were more sensitive to abrasive type, the WC-10Co4Cr coating exhibited significantly higher wear resistance, outperforming the alternatives by 2‒17 times under high abrasive intensity. These findings highlight the potential of HVAF-sprayed WC-10Co4Cr coatings for extending the service life of AlSi7Mg0.3-based fan blades exposed to erosion wear at normal temperatures.

Advancements in biomedical coatings: A comprehensive review of DC magnetron sputtering on Ti–6Al–4V alloy

This study investigates the application of DC magnetron sputtering (MS) technology for producing TiN and ion-substituted Ca-P coatings on dental implant materials, demonstrating ultimate tensile strength (UTS) of 887 MPa, a modulus of elasticity of 11.3 × 106 MPa. The influence of various physical vapor deposition (PVD-MS) parameters—such as substrate temperature, post-heat treatment, deposition duration, discharge power, and bias voltage—on the characteristics of these coatings is examined. The research evaluates the advantages and limitations of PVD-MS in fabricating TiN and Ca-P coatings, with an emphasis on their impact on surface topography and chemical composition, which are critical factors influencing cellular behavior. The study reveals that while ion-substituted HA coatings can enhance cell adhesion, they may also exhibit cytotoxic effects, potentially limiting cell growth. It compares osteogenic cell proliferation rates between low-crystalline HA coatings and highly crystalline variants on Ti-based substrates, highlighting significant performance disparities. Additionally, PVD-MS demonstrates robust adhesion capabilities and facilitates the incorporation of therapeutic ions, effectively replicating bioapatite properties. The addition of coating on the substrate promotes additional strengthening mechanisms of the layers, leading to improved wear resistance compared to an alloyed substrate. Estimated values for hardness range between 7.2 and 8.4 GPa, and for Young's modulus, they range from 126 to 162 GPa. The study highlights the potential of PVD-MS in creating nanostructured Ca-P coatings on biodegradable metals, alloys, and polymeric biomaterials. This technology improves corrosion resistance, biocompatibility, chemical stability, wear resistance, and overall performance in various biomedical applications.

Analysis of Erosion of Surfaces in Falling Particle Concentrating Solar Power

Abstract Next generation concentrating solar power (CSP) systems, which utilize solid particles for energy capture, transport, and storage, offer prospects for higher temperature operation, improved efficiency, and reduced overall costs. Nevertheless, the continuous impingement of particles on component materials can result in substantial erosion, significantly constraining the performance and longevity of the components. A comprehensive understanding of particle erosion on surfaces is essential for designing components and operational parameters or coatings that minimize wear. This study presents a computational physics-based particle tracking model of the erosion rate of incident surfaces under different geometric, operational, and particle parameters. The computational model is validated with experimental measurements conducted as part of the study. Computational simulations are presented to elucidate the effects of each parameter and further used to investigate erosion rates in a systematic design of experiments covering a wide range of parameters. Based on the simulation results, a generalized analytical model is developed to relate erosion wear to pertinent dimensionless groups governing the physics of the process. The analytical model is shown to be accurate to within 10% and its use in understanding surface erosion as well as designing wear-resistant coatings to limit erosion within acceptable values is presented.

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.

Mechanical properties of CoCrFeNi-X (X = Ti,Sn) high entropy alloy and tribological properties in simulated seawater environment

Five multimajor element CoCrFeNi-X(X = Ti,Sn) high entropy alloys (HEA) were prepared by vacuum hot press sintering. The phase composition, mechanical properties and tribological properties of CoCrFeNi-X(X = Ti,Sn) alloys in simulated seawater were investigated. The phase structure of CoCrFeNiTi high-entropy alloy is solid solution FCC phase, R phase, σ phase, and Laves phase. But after addition Sn elements, the phase structure become the FCC phase and Ni-Sn solid solution phase. CoCrFeNiTi alloy has lower density (7.17 g/cm3) and higher hardness (750 HV) than that of CoCrFeNiSn. The compressive yield strength of CoCrFeNiTi HEA is better than CoCrFeNiSn HEA. The CoCrFeNiSn high-entropy alloys showed lower wear rates. The main reason is that SnO2 is generated on the wear scar surface, which has good wetting and corrosion inhibition effects, so CoCrFeNiSn HEA shows better wear resistance in simulated seawater. The main wear mechanism of the CoCrFeNiSn HEA is abrasive wear, oxidative wear, exfoliation wear and corrosive wear.