Search Results (57)

Tribological processes in extreme environments pose serious material challenges, requiring coatings that resist both wear and corrosion. This review summarizes recent advances in protective coatings engineered for extreme environments such as high temperatures, chemically aggressive media, and high-pressure and abrasive domains, as well as cryogenic and space applications. A comprehensive overview of promising coating materials is provided, including ceramic-based coatings, metallic and alloy coatings, and polymer and composite systems, as well as nanostructured and multilayered architectures. These materials are deployed using advanced coating technologies such as thermal spraying (plasma spray, high-velocity oxygen fuel (HVOF), and cold spray), chemical and physical vapor deposition (CVD and PVD), electrochemical methods (electrodeposition), additive manufacturing, and in situ coating approaches. Key degradation mechanisms such as adhesive and abrasive wear, oxidation, hot corrosion, stress corrosion cracking, and tribocorrosion are examined with coating performance. The review also explores application-specific needs in aerospace, marine, energy, biomedical, and mining sectors operating in aggressive physiological environments. Emerging trends in the field are highlighted, including self-healing and smart coatings, environmentally friendly coating technologies, functionally graded and nanostructured coatings, and the integration of machine learning in coating design and optimization. Finally, the review addresses broader considerations such as scalability, cost-effectiveness, long-term durability, maintenance requirements, and environmental regulations. This comprehensive analysis aims to synthesize current knowledge while identifying future directions for innovation in protective coatings for extreme environments. Full article

This study investigates the development of silver (Ag)-doped zirconia (ZrO₂) coatings deposited on 316LVM stainless steel via the unbalanced magnetron sputtering technique. The oxygen content in the Ar/O₂ gas mixture was systematically varied (12.5%, 25%, 37.5%, and 50%) to assess its influence on the resulting coating properties. In response to the growing demand for biomedical implants with improved durability and biocompatibility, the objective was to develop coatings that enhance both wear and corrosion resistance in physiological environments. The effects of silver incorporation and oxygen concentration on the structural, tribological, and electrochemical behavior of the coatings were systematically analyzed. X-ray diffraction (XRD) was employed to identify crystalline phases, while atomic force microscopy (AFM) was used to characterize surface topography prior to wear testing. Wear resistance was evaluated using a ball-on-plane tribometer under simulated prosthetic motion, applying a 5 N load with a bone pin as the counter body. Corrosion resistance was assessed through electrochemical impedance spectroscopy (EIS) in a physiological solution. Additionally, tribocorrosive performance was investigated by coupling tribological and electrochemical tests in Ringer’s lactate solution, simulating dynamic in vivo contact conditions. The results demonstrate that Ag doping, combined with increased oxygen content in the sputtering atmosphere, significantly improves both wear and corrosion resistance. Notably, the ZrO₂-Ag coating deposited with 50% O₂ exhibited the lowest wear volume (0.086 mm³) and a minimum coefficient of friction (0.0043) under a 5 N load. This same coating also displayed superior electrochemical performance, with the highest charge transfer resistance (38.83 kΩ·cm²) and the lowest corrosion current density (3.32 × 10⁻⁸ A/cm²). These findings confirm the high structural integrity and outstanding tribocorrosive behavior of the coating, highlighting its potential for application in biomedical implant technology. Full article

This study investigates the tribo-corrosion behavior of Ti6Al4V biomedical alloy, when sliding against fused filament fabrication (FFF) 3D-printed polyether ether ketone (PEEK) pins in a phosphate-buffered saline (PBS) solution. This research aims to evaluate wear mechanisms and electrochemical responses under simulated physiological conditions, providing critical insights for enhancing the durability and performance of biomedical implants. Potentiodynamic polarization tests demonstrate that the Ti6Al4V alloy possesses excellent corrosion resistance, which is further enhanced under sliding conditions compared to the test without sliding. When tested against 3D-printed PEEK, the alloy exhibits a mixed wear mechanism characterized by both abrasive and adhesive wear. Open-circuit potential (OCP) measurement of Ti6Al4V demonstrates the alloy’s superior electrochemical stability, indicating high corrosion resistance and a favorable coefficient of friction. These findings highlight the potential of 3D-printed PEEK as a viable alternative for biomedical applications, offering rapid patient-specific prototyping, tunable mechanical properties, and improved surface adaptability compared to conventional materials. Full article

This study investigates the tribocorrosion behavior of 304 stainless steel (304SS), S31254 super austenitic stainless steel (S31254 SASS), and a medium-entropy austenitic stainless steel (MEASS) in 3.5 wt.% NaCl solution under sliding conditions. The objective is to clarify the performance differences among these alloys when exposed to simultaneous mechanical wear and corrosion. Electrochemical techniques, including potentiodynamic polarization and potentiostatic sliding tests, were used to evaluate corrosion resistance and repassivation behavior. Quantitative analysis based on ASTM G119 revealed that MEASS showed a 68% lower total material loss compared to 304SS and a 55% lower loss compared to S31254. MEASS also exhibited the lowest corrosion current density (1.46 μA/cm²) under tribocorrosion conditions, representing an 83% reduction compared to 304SS. These improvements are attributed to the higher chromium and nickel contents of MEASS, which enhance passive film stability and reduce susceptibility to localized corrosion. The results demonstrate that MEASS offers superior resistance to combined mechanical and corrosive degradation in chloride-containing environments. Full article

Food security is one of the main problems in several countries. In food processing the cutting operation is very important as the operation is basic to food preparation. Due to cutting tools being exposed to a high-demand environment that includes high contact pressure, a corrosive atmosphere, and a high-speed process, they are subject to high mechanical and corrosive wear that reduces their lifetime and efficiency. Tribocorrosion is one of the main phenomena that reduces the lifetime and efficiency of cutting tools. This work presents electrochemical and tribocorrosion studies of D2 steel surfaces coated with TiN, TiCN, and TiCrN films. The samples were coated by a commercial source, using the PVD-cathodic arc technique. The crystalline structure of TiN and TiCN films presented a TiN and Ti phase, while the crystalline structure of TiCrN showed CrN and Cr phases. The films exhibited good adhesion, but the surfaces coated with TiN and TiCN films presented lower hardness. Although the TiN, TiCN, and TiCrN films showed better wear and corrosion resistance than the D2 steel surfaces, the inclusion of C and Cr in the TiN films decreased the TiN wear and electrochemical resistance in 3.5% (w/w) of NaCl solution. Full article

The increasing demand for lightweight, high-performance materials in marine and offshore engineering has driven the development of hybrid solutions combining metals and composites. This study investigates the stress corrosion cracking (SCC) and tribocorrosion behaviour of a novel hybrid wire consisting of a superaustenitic stainless steel (6Mo) outer shell and a carbon fibre-reinforced polymer (CFRP) core. Microstructural analysis, residual stress measurement, and corrosion testing were performed to assess the integrity of the welded structure under harsh conditions. The results revealed that residual stresses and interdendritic segregation in the weld zone significantly contribute to SCC susceptibility, while the 6Mo steel showed improved corrosion resistance over 316L under tribocorrosion conditions but was more sensitive to the sliding frequency. These findings provide critical insights into the degradation mechanisms of metal composite hybrid wires and support the future design of corrosion-resistant components for offshore and structural applications. Full article

Titanium (Ti) alloys are widely used in biomedical applications but face challenges like poor biological activity and corrosion at modular interfaces. Strontium (Sr)-doped micro-arc oxidation (MAO) surfaces are proposed to improve biocompatibility and tribocorrosion resistance. This study examines the electrochemical behaviour of Ti surfaces treated with 0.0013 M and 0.13 M Sr-doped MAO via open circuit potential, potentiodynamic polarisation, and electrochemical impedance spectroscopy in a basic physiological solution at 37 °C. The results indicate that higher Sr concentrations led to lower passivation current densities (more than two times lower than at the lowest Sr concentration) and reduced barrier layer capacitance (more than one and a half times lower than at the lowest Sr concentration), suggesting improved corrosion resistance for Sr-enriched MAO treatments on Ti implants. Full article

Although extensive studies have examined the tribocorrosion behavior of stainless steels, the performance of medium-entropy austenitic super stainless steels (MEASS) under severe combined corrosion and mechanical wear conditions has not been fully established. This study systematically compares the tribocorrosion behavior of a newly developed MEASS with conventional S31254 super austenitic stainless steel (SASS) in a 1 M H₂SO₄ solution, aiming to explore innovative material designs for enhanced performance under these demanding conditions. Electrochemical tests were conducted under both open-circuit potential (OCP) and cathodic potential, with and without sliding wear, to assess the corrosion, wear, and synergistic effects influencing the tribocorrosion performance. Worn surface morphologies and hardness were analyzed using scanning electron microscopy (SEM), transmission electron microscopy (TEM), and hardness measurements, respectively. The experimental results revealed that MEASS exhibits a superior repassivation capability compared to S31254, with a 34.3% lower total material loss after 24 h of tribocorrosion test, primarily attributed to enhanced strain hardening and improved wear resistance. These findings emphasize the strong potential of MEASS for use in corrosive environments, particularly in chemical processing industries, where high resistance to wear and corrosion is critically required. Full article

This study aims to achieve in situ-formed pure Ti and Ti6Al4V coatings on 316L stainless steel through hot pressing and examine their wear and corrosion properties thoroughly in two simulated body fluids: physiological serum (0.9% NaCl) and Hanks’ solution. The sintering and diffusion bonding process was conducted at 1050 °C under a uniaxial pressure of 40 MPa for 30 min in a vacuum environment of 10⁻⁴ mbar. Following sintering, in situ-formed pure Ti and Ti6Al4V coatings, approximately 1000 µm thick, were produced on 316L substrates approximately 3000 µm in thickness. The mean hardness of 316L substrates, pure Ti, and Ti6Al4V coatings are around 165 HV, 170 HV, and 420 HV, respectively. The interface of the stainless steel substrate and the pure Ti and Ti6Al4V coatings exhibited no microstructural defects, while the interface exhibited significantly higher hardness values (ranging from 600 to 700 HV). The coatings improved corrosion resistance in both electrolytes compared to the 316L substrate. Wet wear tests revealed reduced friction coefficients in 0.9% NaCl relative to Hanks’ solution, highlighting the chemical interactions between the material surface and the electrolyte type and the significance of tribocorrosion in biocoatings. Full article

The study examined the corrosion and wear characteristics of hot-dip galvanized steel in complex soil environments. The results showed that hot-dip galvanized steel exhibited improved corrosion resistance characteristics. Additionally, the sliding speed was observed to influence both the coefficient of friction (COF) and the state of the worn surface. Moreover, the corrosion resistance of hot-dip galvanized steel declined as the immersion period increased. Following the incorporation of friction behavior, the galvanized layer is prone to accelerated degradation. The wear of the galvanized layer resulted in the failure of its electrochemical protection, creating a pathway for corrosion to occur on the substrate as a result of the coupling effect of corrosion and wear. The use of hot-dip galvanized steel presents challenges when exposed to a tribocorrosion environment for a prolonged period. This study lays the groundwork for future research on the maintenance cycle of industrial structures constructed primarily with hot-dip galvanized steel. Full article

High-entropy alloy (HEA) coatings have attracted wide scientific attention in academic research and industrial innovation. In the present paper, the NiCoCrAlY HEA coatings are successfully synthesized on the surface of M50 steel to improve the corrosion resistance and tribocorrosion resistance of M50 steel in salt-contaminated lubricating oil. The corrosion and tribocorrosion behaviors of M50 steel and NiCoCrAlY coatings are studied systemically under the same conditions. The experimental results show that NiCoCrAlY coatings have good, densified microstructures and improve effectively the corrosion resistance and tribocorrosion resistance of M50 steel because the protective passivation films and oxide films are formed on the surface of NiCoCrAlY coatings. NiCoCrAlY coatings have high corrosion potential, a low corrosion current density, and a corrosion rate that is comparable with M50 steel. The corrosion potential of M50 steel decreases and the corrosion current density increases with the increase in load due to wear-induced corrosion. The corrosion and tribocorrosion mechanisms of M50 steel and coatings are discussed in light of the experimental results. The wear mechanism of M50 steel is abrasive wear. It is accompanied by corrosion wear for M50 steel and oxidative wear for NiCoCrAlY coatings. Full article

In this work, a comparative study of the tribological performance of two hard coatings, CrN/TiBN, was conducted for research purposes and industrial applications in food products, particularly for food packaging into cans using the double hermetic sealing process. CrN and TiBN coatings were successfully deposited on a base-cobalt metal substrate of a CoCrW commercial alloy using physical vapor deposition by arc evaporation (AEPVD) technology to improve the tribological properties of the commercial alloy, including wear and corrosion resistance, lower coefficient of friction, and overall durability. This research focuses on conducting scratch and abrasion wear resistance tests in dry conditions; specifically, it pursues to evaluate the wear corrosion properties, known as tribocorrosion performance, on CrN/TiBN hard coatings. The experimental results show that the CrN coating (2.9 μm) is slightly thicker than the TiBN coating (2.7 μm), with a 47 N critical load. It also shows a lower coefficient of friction (CoF) in a dry environment, while the TiBN coating showed total detachment and a high coefficient of friction in a dry environment condition. Tribocorrosion testing in brine aqueous solution indicated that CrN coating shows a high friction coefficient with a higher open circuit potential value (E_corr), and TiBN shows the lowest corrosion potential (E_corr) and the lowest friction coefficient. This suggests that CrN could provide better corrosion protection for commercial cobalt alloys and improve tool performance during the food canning process in brine environments. Full article

This study investigates the tribocorrosion performance of a cast Co-Cr-Mo alloy prepared using casting and electromagnetic stirring (EMS) at specific frequencies. The tribocorrosion behaviour of the alloy was evaluated when exposed to Ringer’s lactate solution to optimize the EMS parameters and improve its properties. The research focuses on biomedical implant applications and explores how EMS affects alloy wear and corrosion resistance. As did the friction coefficient and wear volume, the wear rate of samples produced with EMS frequencies of 75 Hz and 150 Hz decreased. These improvements are attributed to the ability of EMS to refine grain size and homogenize the microstructure, thereby increasing the resistance to tribocorrosion. Techniques such as scanning electron microscopy (SEM) and profilometry were used for surface and wear analysis, while mechanical properties were evaluated through instrumented indentation tests. The findings confirm that EMS improves the alloy’s durability and tribocorrosion resistance, making it highly suitable for demanding biomedical applications such as joint replacements. This highlights the importance of advanced manufacturing techniques in optimizing biomedical alloys for simulated body conditions. Full article

Additive manufacturing (AM) of orthopedic implants has increased in recent years, providing benefits to surgeons, patients, and implant companies. Both traditional and new titanium alloys are under consideration for AM-manufactured implants. However, concerns remain about their wear and corrosion (tribocorrosion) performance. In this study, the effects of fretting corrosion were investigated on AM Ti-29Nb-21Zr (pre-alloyed and admixed) and AM Ti-6Al-4V with 1% nano yttria-stabilized zirconia (nYSZ). Low cycle (100 cycles, 3 Hz, 100 mN) fretting and fretting corrosion (potentiostatic, 0 V vs. Ag/AgCl) methods were used to compare these AM alloys to traditionally manufactured AM Ti-6Al-4V. Alloy and admixture surfaces were subjected to (1) fretting in the air (i.e., small-scale reciprocal sliding) and (2) fretting corrosion in phosphate-buffered saline (PBS) using a single diamond asperity (17 µm radius). Wear track depth measurements, fretting currents and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) analysis of oxide debris revealed that pre-alloyed AM Ti-29Nb-21Zr generally had greater wear depths after 100 cycles (4.67 +/− 0.55 µm dry and 5.78 +/− 0.83 µm in solution) and higher fretting currents (0.58 +/− 0.07 µA). A correlation (R² = 0.67) was found between wear depth and the average fretting currents with different alloys located in different regions of the relationship. No statistically significant differences were observed in wear depth between in-air and in-PBS tests. However, significantly higher amounts of oxygen (measured by oxygen weight % by EDS analysis of the debris) were embedded within the wear track for tests performed in PBS compared to air for all samples except the ad-mixed Ti-29Nb-21Zr (p = 0.21). For traditional and AM Ti-6Al-4V, the wear track depths (dry fretting: 2.90 +/− 0.32 µm vs. 2.51 +/− 0.51 μm, respectively; fretting corrosion: 2.09 +/− 0.59 μm vs. 1.16 +/− 0.79 μm, respectively) and fretting current measurements (0.37 +/− 0.05 μA vs. 0.34 +/− 0.05 μA, respectively) showed no significant differences. The dominant wear deformation process was plastic deformation followed by cyclic extrusion of plate-like wear debris at the end of the stroke, resulting in ribbon-like extruded material for all alloys. While previous work documented improved corrosion resistance of Ti-29Nb-21Zr in simulated inflammatory solutions over Ti-6Al-4V, this work does not show similar improvements in the relative fretting corrosion resistance of these alloys compared to Ti-6Al-4V. Full article

Ti/TiN/(Ti,N)-DLC/Ti-DLC/DLC coatings were deposited on 431 stainless steel using direct current magnetron sputtering technology under different bias voltages(0 V, −100 V, −200 V and −300 V). The microstructure and tribocorrosion performance of these DLC coatings in seawater was investigated. The results indicated that under the bias voltages, a denser and smoother surface of DLC coatings with a higher bonding strength between coatings and substrates was observed related to the increased incident kinetic energy of deposited ionized atoms. When the bias voltage was −200 V, the surface roughness reduced from 9.81 nm to 7.03 nm, and the bonding strength enhanced from 8.23 N to 8.86 N. What is more, the sp³ bond proportion and the disorder degree in DLC coatings both increased, which resulted in improved hardness and deformation resistance. However, when the bias voltage was −300 V, the increase of the amorphization was associated with a simultaneous rise in internal stress, which reduced the hardness and bond strength a little (8.72 N). DLC coatings can effectively improve the tribocorrosion properties of 431 stainless steel in seawater. When the voltage was −200 V, the average friction coefficient decreased from 0.35 to 0.07, with shallower wear traces and the wear loss of the DLC coating also being the smallest. The abrasive wear caused by metal oxides falling off the grinding ball, and the plastic deformation of the DLC coatings are the main wear forms. The high-density structure of DLC coatings under bias voltages can not only prevent the rapid expansion of cracks during deformation, but also provides a physical barrier to the erosion, which improves the corrosion and friction resistance in seawater. The optimization of bias voltage can improve the tribological performance of DLC coatings by regulating the carbon chain bond and microstructure. These results provide reference for DLC preparation and their potential engineering applications in stainless steel. Full article