Tribocorrosion Behavior Research Articles

Microstructure and tribocorrosion behaviors of Fe–Al–Ti coatings prepared by the aluminothermic reaction

To improve the tribocorrosion resistance of 316L stainless steel in acidic media, Fe–Al–Ti coatings were prepared on 316L substrate by self-propagating high-temperature synthesis (SHS) using an aluminothermic reaction. The effects of Ti content on the tribocorrosion behaviors of Fe–Al–Ti coatings in 0.5 mol/L H2SO4 solutions were investigated. The Fe–Al–Ti coatings exhibited a multi-phase microstructure. The open circuit potential (OCP) of the Fe–Al–Ti coatings and 316L substrate decreased significantly with the onset of sliding, indicating a strong wear-corrosion synergistic effect. The hardness and tribocorrosion resistance of Fe–Al–Ti coatings increase with increasing the Ti content. The tribocorrosion volume loss of the Fe–25Al–25Ti coating was about one order of magnitude lower than that of the 316L substrate. The Fe–25Al–25Ti coating was more suitable as a tribocorrosion-resistant material than the 316L substrate.

Tribo-corrosive wear behaviour of squeeze-casted Mg/TiN/hBN composite under different ageing temperature

The combined and individual effects of adding hard TiN ceramic particles and soft hBN solid lubricant particulates on AZ91D magnesium alloy were studied by analysing the tribocorrosion behaviour under various ageing conditions. The proposed materials were fabricated through the Stir-Ultrasonication-Squeeze casting technique and T6 heat treated at various ageing temperatures (170, 200, 230, and 260 °C). The tribocorrosion test results revealed that the ‘AHTT’ hybrid composite had a high corrosion potential (Ecorr) of − 1.38 V, low corrosion current density (Icorr) of 1.82 × 10−6 A cm−2 and low corrosion rate of 0.049 mm/yr. at 200 °C due to grain strengthening, formation of protective tribo-films and H3BO3 precipitates reduce the oxidation reaction during wear and corrosion. At a temperature of 200 °C, the nyquist plot reveals the presence of capacitive loops at both high and medium frequencies, which can be attributed to the formation of a thick tribo film layer that functions as a protective barrier. Furthermore, the stable reprecipitated secondary β-Mg17Al12 acts as a cathode, effectively restricting the formation of Mg+ ions.

Tribocorrosion Behavior of γ′-Fe4N Nitride Layer Formed on Mild Steel by Plasma Nitriding in Chloride-Containing Solution

Nitriding has long been used to engineer the surfaces of engineering steels to improve their surface and subsurface properties. The role of the surface compound layer (γ′-Fe4N and/or ε-Fe2-3N) in improving the tribological and corrosion-resistant properties of nitrided steels has been established. However, there have been very few studies on the response of the compound layer to tribocorrosion in corrosive environments. In this work, the tribocorrosion behavior of a 5 μm thick γ′-Fe4N nitride layer produced on mild steel (MS) by plasma nitriding has been studied in a NaCl-containing solution under various electrochemical conditions. The results show that at a cathodic potential of −700 mV (saturated calomel electrode, SCE), where mechanical wear is predominant, the total material removal (TMR) from the γ′-Fe4N layer is 37% smaller than that from the untreated MS, and at open circuit potential, TMR from the layer is 34% smaller than that from the untreated MS, while at an anodic potential of −200 (SCE), the γ′-Fe4N layer can reduce TMR from mild steel by 87%. The beneficial effect of the γ′-Fe4N nitride layer in improving the tribocorrosion behavior of mild steel is derived from its high hardness and good corrosion resistance in the test solution and its ability to resist both mechanical wear and corrosion and to reduce wear–corrosion synergism.

Tribo-corrosion behavior of C-steel in water-based emulsion drilling fluids containing green corrosion inhibitors: experimental and computational studies

This article reports a study on the corrosive wear of carbon steel in water-based emulsion drilling fluids containing green corrosion inhibitors, PEG-6 isotridecyl phosphate and PEG-2 oleamide. The latter was used for comparison purposes, which was previously demonstrated to exhibit good performance. The effectiveness of the drilling fluids with the inhibitors, especially PEG-6 isotridecyl phosphate, in suppressing tribo-corrosion was largely improved, evidenced by much lowered corrosion rate, coefficient of friction (COF) and tribo-corrosion, compared to those without the green inhibitors. The benefits of the inhibitors were influenced by the sliding speed (2, 3.5, 5 and 10 mm/s). With increasing the sliding speed from 2 mm/s to 5 mm/s, the corrosion rate decreased, but further increasing the sliding speed to 10 mm/s did not continuously reduce the corrosion rate. However, COF value of carbon steel was continuously decreased as the sliding speed increased from 2 to 10 mm/s. It was shown that the corrosion inhibitors resulted in a more protective film on the worn surfaces, and the adsorption equilibrium constants increased with respect to the sliding speed from 182.6 M−1 to 849.6 M−1 for PEG-6 isotridecyl phosphate and 6.70 M−1 to 28.1 M−1 for PEG-2 oleamide. First-principles calculations and molecular dynamics simulations demonstrated that the better performance of the PEG-6 isotridecyl phosphate inhibitor was ascribed to its stronger polymer film and higher adherence to the iron surface.

Investigation of surface wettability, corrosion and tribocorrosion behavior of machined, etched, blasted and anodized Cp-Ti samples

Investigation of surface wettability, corrosion and tribocorrosion behavior of machined, etched, blasted and anodized Cp-Ti samples

Impact-sliding fretting tribocorrosion behavior of 316L stainless steel in solution with different halide concentrations

Impact-sliding caused by random vibrations between tubes and supports can affect the operation of heat exchangers. In addition, a corrosive environment can cause damage, accelerating the synergism of corrosion and wear. Therefore, the focus of this work was the impact-sliding fretting tribocorrosion behavior of 316L heat exchanger tubes at different halide concentrations. A device system incorporating the in situ electrochemical measurements of impact-sliding fretting corrosion wear was constructed, and experiments on 316L heat exchanger tubes in sodium chloride (NaCl) solution with different concentrations (0.0, 0.1, 0.5, 1.0, 3.5, and 5.0 wt%) were carried out. The synergism between wear and corrosion was also calculated and analyzed. The wear and damage mechanisms were elucidated by correlating the corrosion-wear synergism, morphologies, and material loss rates. The results indicated that the stable wear stage occurred at approximately 9–12 h, after which the corrosion current increased with the expansion of the wear area. As the halide concentration increased, the scale of damage on the wear scars gradually decreased, changing from being dominated by cracks, delaminations, and grooves to being dominated by scratches, microgrooves, and holes. There was an obvious positive synergism between wear and corrosion. The material loss was dominated by pure mechanical wear and wear enhanced by corrosion, but corrosion enhanced by wear contributed more than tangential sliding fretting corrosion. The total mass loss increased gradually in the range of 0.0–0.5 wt% and decreased in the range of 0.5–5.0 wt%. Large-scale damage enhanced by corrosivity and small-scale damage reduced by lubricity dominated the material loss at low and high concentrations, respectively.

Enhanced corrosion and tribocorrosion behavior of plasma electrolytic oxidized coatings on 5052 aluminum alloy with addition of pullulan to silicate electrolyte

Plasma electrolytic oxidation (PEO) ceramic coatings were fabricated on a 5052 aluminum (Al) alloy using a silicate-based electrolyte with the pullulan addition, and the effects of different pullulan concentrations on the corrosion and tribocorrosion resistance of the coatings were investigated. The morphology, chemical composition, phase structure, and mechanical properties of the coatings were observed via scanning electron microscopy, energy-dispersive spectroscopy, X-ray diffraction, and scratching. The corrosion and tribocorrosion properties were evaluated via electrochemical tests and tribocorrosion tests in a 3.5 wt% NaCl solution, respectively. As a result of the pullulan addition, the phase structure of the coatings was slightly affected, but their microstructure and mechanical properties were significantly altered. The PEO coating displayed the smallest pore size and densest structure at a concentration of pullulan addition of 1.0 g/L. The corrosion current density of PEO coating was 2.41 × 10−8 A/cm2, which was two orders of magnitude lower than that of the Al alloy substrate. In addition, under tribocorrosion conditions, the wear rate of PEO coating was only 4.6 × 10−6 mm3N−1m−1, which was 91.8 % lower than that of the substrate, indicating excellent corrosion and tribocorrosion resistance. This study provides guidelines for the development of a sustainable and eco-friendly corrosion inhibitor for PEO coatings on Al alloys.

Fabrication of tailored Ti6Al4V-based materials by conventional powder metallurgy for bone implant applications

ABSTRACT This works proposes a methodology for fabricating materials with specific characteristics mimicking human bones. A Ti64 alloy powder was used as the base material and it was mixed with Ag, Ta, TiN and salt particles to obtain different features. A hip-bone like component was fabricated, including a highly porous core of Ti64/25Ta/5Ag and a compact outer shell of Ti64/5Ag that is supposed to improve corrosion and osseointegration. Besides, a harder cover surface in Ti64/10TiN composite should increase the wear resistance. The green component was sintered at 1260°C in argon. Its Young’s modulus was close to the one of bones due to the added porosity, which also provided a permeability close to the one reported for trabecular bones. Tribocorrosion behaviour in simulated body fluid was improved by TiN addition. In conclusion, the proposed processing route was able to produce complex components fulfilling specific features required for human bone replacement.

Correlation of microstructure and bio-tribocorrosion behavior of equal channel angular pressed pure titanium

The effect of equal channel angular pressing (ECAP) strain (i.e., 1st to 4th pass) on the grain size and eventual mechanical and bio-tribocorrosion properties of commercially pure titanium (cp-Ti) has been investigated. Ultra-fine grains (UFG) of 0.8 µm size (from 12 µm) and yield strength enhancement to 785 MPa (from 381 MPa) have been observed for the ECAP 4th pass sample as compared to the annealed condition of cp-Ti. In addition, the maximum hardness increased by 101 HV to 293 HV in the 4th pass samples due to grain refinement caused by the ECAP process. Further, the tribocorrosion behaviour as a function of cp-Ti sample conditions in the simulated body fluid (SBF) has been evaluated. The ultra-fine-grained 4th pass sample shows a lower coefficient of friction (CoF) of ∼0.35 (from ∼0.5) and wear loss due to its enhanced strength than the annealed sample. Moreover, the ECAP 4th pass sample, because of its UFG, exhibits a more negative potential shift (∼0.82 V) as compared to annealed sample (∼0.88 V). However, this shift is marginal due to its low wear scar width and depth, which eventually induced less galvanic coupling effect in it. Abrasion and adhesion are the primary wear mechanisms for all the sample conditions.

Tribocorrosion behavior of high-entropy alloys FeCrNiCoM (M = Al, Mo) in artificial seawater

A corrosion, wear and synergism behaviors between them of the high-entropy alloys (HEAs) FeCrNiCo(I-0), FeCrNiCoAl(I-Al) and FeCrNiCoMo (I-Mo) in artificial seawater were studied quantitatively. The I-Al has small coefficient of friction and large wear rate because the Al dissolve preferentially. The wear rate of I-Mo is the smallest for the wear debris containing molybdate fills in the corrosion pits where the FCC phase is corroded firstly. The wear is main cause of the tribocorrosion compared with the corrosion. The corrosion rate increases due to the wear is 100 times larger than the wear rate increases due to the corrosion.

Effects of nanosecond laser shock peening on residual stress, corrosion and tribocorrosion behavior of WE43 magnesium alloys

Biodegradable magnesium (Mg) alloys are promising candidates for use as next-generation implants due to their similar mechanical properties to natural bones, excellent biocompatibility, and the ability to completely degrade in vivo. However, a great challenge of Mg alloys in physiological environments is their fast corrosion rate and low tribocorrosion resistance, which makes it difficult to ensure adequate structural integrity over the required time for complete tissue and bone healing. In this work, the effects of nanosecond laser shock peening (ns-LSP) processing parameters on the surface tribocorrosion resistance of WE43 Mg alloys was investigated. The laser power densities and overlapping ratios were tuned to control the magnitude and depth of residual stresses and the amount of cold work. The tribocorrosion behaviors of WE43 Mg after the ns-LSP treatment were measured in stagnant blood bank buffered saline (pH of 7.0–7.2) under ∼ 37 °C. The tribocorroded surfaces were characterized via X-ray diffraction, scanning electron microscope and energy dispersive spectroscopy. It was found that the optimum peening effect was achieved at lower laser power density and overlapping ratio, where the corrosion cathodic reaction rate was decreased and tribocorrosion rate was reduced by 47.8%, compared to those of the untreated samples. The established processing-performance (i.e., surface hardness, corrosion and tribocorrosion) relationship in this study could shed light on the future LSP process optimization for enhancing surface properties of Mg alloys.

Investigation of the Influence of High-Pressure Torsion and Solution Treatment on Corrosion and Tribocorrosion Behavior of CoCrMo Alloys for Biomedical Applications

In this study, the influence of the high-pressure torsion (HPT) processing parameters and solution treatment (ST) on the corrosion and tribocorrosion behavior of CoCrMo (CCM) alloys was investigated for possible usage in biomedical applications. The corrosion behavior of the CCM alloys was investigated by using potentiodynamic scanning (PDS) and electrochemical impedance spectroscopy (EIS) tests. Tribocorrosion tests were carried out in a reciprocating ball-on-plate tribometer at 1 Hz, 1 N load, and 3 mm stroke length for 2 h. All electrochemical measurements were performed using a potentiostat in standard phosphate-buffered saline (PBS) solution at body temperature (37 ± 2 °C). The samples were characterized by using a scanning electron microscope (SEM), transmission electron microscope (TEM), optical microscope (OM), and X-ray diffraction (XRD). The deepness and width of wear tracks were examined by using a profilometer. The results showed that HPT and ST processes did not affect significantly the corrosion resistance of samples. However, the ST-treated samples had a higher material loss during sliding in standard phosphate-buffered saline (PBS) at body temperature as compared to HPT-treated samples.

Effect of ultrasonic surface rolling process on the fretting tribocorrosion behaviors of Inconel 690 alloy

The ultrasonic surface rolling process (USRP) is conducted by making the metal surface undergo micro-plastic deformation to improve its surface state and some mechanical properties, thus strengthening its tribocorrosion resistance. In this study, the surface of the Inconel 690 alloy block was treated by special USRP, and the change in its tribocorrosion behaviors had been effectively revealed by a fretting electrochemical corrosion test rig. Results showed that the Inconel 690 alloy’s tribocorrosion degree and corrosion rate were evidently reduced after USRP. These results could be attributed to the surface finish reduction and surface grain refinement caused by USRP.

The Electroless Monolayer and Duplex Ni–B and Ni–P Coatings for 316L Stainless Steel in Synergistic Combination of Mechanical (Wear) and Chemical (Corrosion) Processes

Conventional processes are performed to improve the low hardness and low wear resistance properties of 316L steel, but these processes generally decrease the corrosion resistance. Electroless nickel alloy coatings provide a hard, wear‐resistant, and corrosion‐resistant surface. Thus, the present study aims to investigate the wear, corrosion, and tribocorrosion behaviors of monolayer and duplex coatings with nickel–boron (Ni–B) and nickel–phospore (Ni–P) on 316L steel in comparison with 316L steel in dry sliding and 0.9 wt% NaCl solution environments. It is determined that the coatings have a mixture of crystal and amorphous structures, the interfaces on the 316L are uniform, and the compatibility between the layers is good. The Ni–B, Ni–P/Ni–B, and Ni–B/Ni–P coatings are 2.3, 2.06, and 1.6 times as hard as the 316L, respectively. The wear rates of Ni–B, Ni–P/Ni–B, and Ni–B/Ni–P coatings show decrease by 99.3%, 92.5%, and 99.1% in the dry‐sliding condition and by 98.5%, 30.1%, and 19.1% in the tribocorrosion condition compared with that of 316L, respectively. It is observed that the monolayer Ni–B coating exhibits superior hardness, a higher contact angle, low electrical conductivity, and better tribological performance in both dry sliding and tribocorrosion conditions compared to the 316L and duplex coatings.

Development of Ti–Al–V alloys for usage as single-axis knee prostheses: evaluation of mechanical, corrosion, and tribocorrosion behaviors

Single-axis knee prosthesis is an artificial biomechanical device that provides motion to amputees without the need for assistance appliances. Besides it is mainly composed of metallic materials, the current commercial materials did not group adequate properties for long-term usage or accessible cost. This study produced and characterized Ti-(10 −x)Al-xV (x = 0, 2, and 4 wt.%) alloys for potential use as single-axis knee prostheses. The samples exhibited a gradual decrease in the density values, with proper chemical mixing of the alloying elements on the micro-scale. The phase composition exhibited a primary α phase with a minor α′ + β phase for the Ti-8Al-2V and Ti-6Al-4V samples. Due to their different atomic radius compared to Ti, the addition of alloying elements changed the cell parameters. Their selected mechanical properties (Young’s modulus, Vickers microhardness, and damping factor) performed better values than the CP-Ti grade 4. The samples also exhibited good corrosion properties against the simulated marine solution. The tribocorrosion resistance of the samples was better than the reference material, with the wear tracks composed of some tribolayers and grooves resulting from adhesive and abrasive wear. The Ti-10Al alloy displayed the best properties and estimated low cost to be used as single-axis knee prostheses.

Tribocorrosion behavior of graphene-based solid lubricants biofunctionalized with hyaluronic acid on CoCr surfaces

In this work graphene-based solid lubricants biofunctionalized with hyaluronic acid were deposited on CoCr surfaces to decrease wear-corrosion phenomena. Graphene oxide was electrochemically reduced on CoCr in an aqueous suspension of graphene oxide 4 g/L by cyclic voltammetry. Biofunctionalization in phosphate buffer solution with HA 3 g/L (PBS-HA) for 24 h was performed. A pin-on-disk tribometer with an integrated cell was used for tribocorrosion tests. Wear-corrosion tests were performed against AISI316 steel balls applying normal load 1 N, 120 rpm for 500 m, in PBS and PBS-HA. Coefficients of friction in PBS were higher than in PBS-HA. ErGO and HA-ErGO increased wear rate in AISI316 balls, i.e., ErGO hardens the CoCr surface. Biofunctionalization reduces abrasive properties of ErGO deposits.

Assessment of improved tribocorrosion in novel in-situ Ti and β Ti–40Nb alloy matrix composites produced with NbC addition during arc-melting for biomedical applications

Nontoxic and nonallergenic β-type Ti–Nb alloys are considered attractive metallic materials for long-term bone implant applications. However, metallic implants present poor wear resistance, and the degradation process can be intensified with the friction occurring in corrosive body fluids, such as joint prostheses. The present study aimed to improve the tribological behavior of Ti–Nb alloys by adding hard reinforcement. The applied strategy is based on in-situ conditions, in which the reinforcing phase can be synthesized during the fabrication of the composite. Thus, a strong interfacial bond can be achieved due to the high chemical compatibility between the matrix and the reinforcement. Therefore, two different in-situ composites were developed by adding NbC powder to Ti and β Ti–40Nb alloy during the arc-melting process. As-cast samples of Ti and β Ti–40Nb alloy without NbC were used as the control groups. Structural characterization was performed, along with corrosion and tribocorrosion tests in a phosphate-buffered solution at body temperature. Results demonstrated that in-situ reactions occurred during the arc-melting process and promoted the precipitation of TiC as the reinforcing phase surrounded by α Ti phase (when NbC was added to Ti), and by β Ti–Nb phase (when NbC was added to Ti–40Nb). Finally, both produced composites showed improved tribocorrosion behaviors with wear volumes less than half of that recorded by the unreinforced Ti and β Ti–40Nb alloy. Thus, this study presents promising alternatives for wear-resistant biomedical applications.

Tribocorrosion of stainless steel sliding against graphite in FLiNaK molten salt

The molten salt reactor (MSR) concept recently gained renewed interest in developing Generation IV nuclear reactors. One MSR design uses fluoride molten salts to cool tri-structural isotropic particle fuel encapsulated by a carbon matrix into spherical pebbles, which would inevitably contact the reactor's stainless steel container wall during salt circulation. Characterizing this interaction is crucial for reactor safety. Here we report the tribocorrosion behavior of graphite sliding against Type 316H stainless steel lubricated by a FLiNaK (LiF:NaF:KF; 46.5:11.5:42 mol %) molten salt in an argon environment. Accelerated wear loss was observed at a higher temperature because of a lower molten salt viscosity and a higher corrosion rate. The graphite had a more rapid material loss at a higher sliding speed than stainless steel because of its higher vulnerability to vibration-induced microfracture. The salt-starved condition caused more material loss than either the no-salt or the salt-flooded condition because neither a graphite transfer film nor stable boundary lubrication could be established at salt starvation. An interesting dual-layer surface film was discovered on the stainless steel worn surface: a chromium-rich top film and a nickel-accumulated but chromium-depleted interlayer. The film composition and structure provide fundamental insights to the mechanochemical interactions between stainless steel and graphite in a molten salt environment.

The Effect of a Duplex Surface Treatment on the Corrosion and Tribocorrosion Characteristics of Additively Manufactured Ti-6Al-4V

The use of additively manufactured components specifically utilizing titanium alloys has seen rapid growth particularly in aerospace applications; however, the propensity for retained porosity, high(er) roughness finish, and detrimental tensile surface residual stresses are still a limiting factor curbing its expansion to other sectors such as maritime. The main aim of this investigation is to determine the effect of a duplex treatment, consisting of shot peening (SP) and a coating deposited by physical vapor deposition (PVD), to mitigate these issues and improve the surface characteristics of this material. In this study, the additive manufactured Ti-6Al-4V material was observed to have a tensile and yield strength comparable to its wrought counterpart. It also exhibited good impact performance undergoing mixed mode fracture. It was also observed that the SP and duplex treatments resulted in a 13% and 210% increase in hardness, respectively. Whilst the untreated and SP treated samples exhibited a similar tribocorrosion behavior, the duplex-treated sample exhibited the greatest resistance to corrosion-wear observed by the lack of damage on the surface and the diminished material loss rates. On the other hand, the surface treatments did not improve the corrosion performance of the Ti-6Al-4V substrate.

Ascertaining the Si-substitution on the tribo-corrosion behaviors of Ti3AlC2 in molten Solar Salt

As a promising working medium for thermal transportation, nitrate-based molten salts are widely adopted for current concentrating solar power (CSP) plants. However, their corrosive nature also brings severe safety hazards to the system, e.g., the impellers and cover in molten salt pumps. To study the potential application of MAX ceramics as a proactive coating for these parts, tribo-corrosion behaviors of Ti3AlC2 and its Si-substituted analogs against GCr15 steels are evaluated in the molten Solar Salt at 300 °C to simulate the operating condition of the cold-salt pump. The Si-substituted MAXs present higher anti-wear performance than pristine Ti3AlC2. With an optimal composition of Ti3Al0.6Si0.4C2, about a 25% reduction in mean wear rate to that of Ti3AlC2 is achieved. Through a comprehensive analysis of the morphological and chemical states of both tribo-corroded and static corroded surface, the effects of Si on the tribo-corrosion behaviors of Ti3AlC2 is illuminated. The enhanced performance after Si addition is ascribed to the facilitated formation of aluminosilicates as corrosion products on the surface, which act as a lubricant as well as impeding the dissolution of Al into the molten Solar Salt.