Tribocorrosion Conditions Research Articles

Effects of Mo content on corrosion and tribocorrosion behaviours of Ti-Mo orthopaedic alloys fabricated by powder metallurgy

Effects of Mo content on corrosion and tribocorrosion of Ti-(8–20)Mo alloys fabricated by powder metallurgy (PM) were investigated. With a higher Mo content, the Ti-Mo alloys showed an increased corrosion resistance, and correspondingly their tribocorrosion resistance presented an initial increase but a subsequent decrease. Ti-16Mo alloy possessed the lowest wear rate of 1.0 × 10−3 mm3/m•N under tribocorrosion condition, which was about 30 % of that of as-cast pure Ti (3.3 × 10-3 mm3/m•N) and 91 % of that of Ti-6Al-4 V alloy (1.1 × 10-3 mm3/m•N), respectively. The highest tribocorrosion resistance and adequate corrosion resistance make the Ti-16Mo alloy a promising candidate for orthopedic applications.

Corrosive and tribocorrosive behavior of plasma powder coatings

Purpose. To investigate corrosion and tribocorrosion characteristics of plasma-powder coatings on the basis of iron, nickel and Fe-Ni system in the envyronments containing chlorides, hydrogen sulfide and ammonia. Metodology: corrosive-electrochemical, tribological, metallographic methods have been used.Results It was established that as the pH of the solution increases, the corrosion resistance of the coatings increases. The highest corrosion resistance has a surfaced layer based on nickel 06Х17Н80С3Р3, however, under tribocorrosion conditions, fragile component of coatings form an abrasive in the friction zone that intensifies the destruction. Compared to others, the coating 06Х17Н80С3Р3 has the lowest resistance to corrosion-mechanical destruction.The fragile component is absent in layers, deposited from powders 01H17N8S6G and 08Х17Н35С3Р. The solid phases are uniformly distributed in a plastic matrix corresponding to the Sharpi-Bochvar rule. In this coatings, the contact interaction occurs in the absence of abrasive wear, which explains the high resistance to tribocorrosion.It is possible to qualitatively evaluate the processes of formation and destruction of secondary structures in the friction zone of tribocorrosion by comparing of the corrosion potentials, tribocorrosion potentials and passivation potentials. Additional information may be provided by the level of local oscillations of the tribopotential, which characterizes the repassivation rate.Practical result. A new composition 08Х17Н35С3Р3 for plasma-powder coatings has been proposed to increase the wear and corrosion resistance of steel surface.

Passivation Layer Tailoring Using Laser Powder-Bed Fusion Additive Manufacturing: A Tribocorrosion Study

Laser powder-bed fusion is an additive manufacturing high-energy laser beam creating near-end shape parts directly from a digital computer model. This technique has revealed new trends in manufacturing industry by producing parts with complex geometry and with topology optimizing the weight to strength ratio of structures. In this research, we characterize the corrosion behavior of a Ti6Al4V and AlSi12 alloy fabricated by using laser powder-bed fusion (L-PBF) when they were exposed to corrosive and tribocorrosion conditions. Two synthesis pathways (vertical and horizontal) were employed to produce alloy disks by using high and low laser power resulting in four different thermo-history profiles. The superfine microstructure of L-PBFed Ti6Al4V was revealed using EBSD and XRD, identified as α’ structure (an oversaturated HCP phase) with an n-type titanium oxide passive layer. The surface property was tailored by different 3D printing parameter resulting in a 30% increase in hardness 60% in wear loss and 28% decrease in the oxygen vacancies. The difference in oxygen vacancies tuned the corrosion to wear ratio from 25% to 15% at 2N normal load in simulated body fluid. The corrosion behavior of L-PBFed AlSi12 was tested in simulated acid water. The two different melt pool microstructure (shown in Fig1 (a) and (b)) engineered by the L-PBF building direction results in a difference in the suspiciously of pitting corrosion. The horizontal built specimens show better in pitting resistance, but with a broader probability distribution, which increases the uncertainty in engineering structurer design. The coarse grain silicon precipitation at melt pool boundary result in localized cathode barrier that deflects the pit propagation resulting in shallow pits. However, the heterogeneity of grain boundaries leads to the weakness in forming a protective surface layer under Cl- attack. Figure 1 (a) Pit morphology and (b) melt pool structure and (c) accumulated pitting probability of AM-AlSi12 in dilute Harrison’s solution Figure 1

Tribological and tribocorrosion behavior of nickel sliding against oxide ceramics

Nickel is widely used as a coating material in electroplating because of its good corrosion and wear resistance even at high temperature. Tribocorrosion has been identified as one of the main degradation mechanisms of nickel. This study evaluated the tribocorrosion behavior of pure nickel in citrate buffer solution (pH 4.5) under controlled mechanical, chemical and electrochemical conditions as well as wear of pure nickel in dry condition sliding against alumina or zirconia balls, respectively. The results showed that the wear of nickel was higher in passive domain due to wear accelerated corrosion compared to that in the cathodic domain. Surprisingly, both alumina and zirconia were worn by nickel in tribocorrosion condition under passive potentials as well as in dry condition. However, in the cathodic domain, negligible wear was observed on the alumina and zirconia balls. The formation of mixed nickel and aluminum/zirconium oxides was proposed as the wear mechanism of alumina and zirconia.

Low Stress Abrasion-Corrosion of High-Cr White Cast Iron: Combined Effects of Particle Angularity and Chloride Ions

Tribo-electrochemical behavior of a high chromium white cast iron (high-Cr WCI) used in, e.g., slurry pumps in mining and mineral processing applications, was investigated using a combination of electrochemical techniques, including zero resistance amperometry as well as potentiostatic and potentiodynamic polarisation. The effects of third body particles angularity on the localised tribocorrosion response of the cast alloy was studied during and post abrasion-corrosion by round ceramic beads and semi-angular silica sand particles. Advanced characterization methods such as electron backscatter diffraction and focused-ion beam cross-sectioning of affected areas were also employed to understand the wear and corrosion interactive actions. It was found that in chloride-free solutions, the behavior of high-Cr WCI resembled that of the austenitic 316 SS studied before. In contrast, in chloride-containing electrolytes, the semi-angular silica sand particles increased interfacial (carbide/matrix) localised corrosion susceptibility during and post-abrasion as indicated by the stark increase in anodic current and the morphology of the attack. Semi-angular silica sand abrasives had a greater adverse impact on post-abrasion interfacial corrosion vulnerability, compared to round ceramic beads. The complex behavior observed indicates that any material developed for tribocorrosive conditions must account for the particles angularity and their subsequent effects on localised corrosion.

Raman Spectroscopy for Reliability Assessment of Multilayered AlCrN Coating in Tribo-Corrosive Conditions

In this study, a multilayered AlCrN coating has been employed as a protective layer for steel used in tribo-corrosive conditions. The coating was deposited by a lateral rotating cathode arc PVD technology on a AISI 316L stainless steel substrate. A ratio of Al/(Al + Cr) was varied from 0.5 up to 0.6 in the AlCrN layer located above Cr adhesion and gradient CrN interlayers. A Raman spectroscopy and potentiodynamic polarization scan were used to determine the resistance in tribo-corrosive (3.5 wt % NaCl) conditions. Correlation between sliding contact surface chemistry and measured tribological properties of material was supported with static corrosion experiments. The corrosion mechanisms responsible for surface degradation are reported.

Corrosion assessment of Ti-6Al-4V fabricated using laser powder-bed fusion additive manufacturing

We describe the interfacial characteristics of a Ti-6Al-4V alloy fabricated using laser powder-bed fusion (L-PBF) upon exposure to a corrosive environment and tribocorrosion conditions. Electrochemical techniques in both the time and frequency domains demonstrated a correlation between the manufacturing process parameters and corrosion properties, and a titanium oxide passive layer produced specific semiconductor n-type properties. The influence of the microstructure on the titanium oxide passive layer was revealed by comparing L-PBF parts with a traditionally manufactured Ti-6Al-4V alloy in Ringer's simulated body solution. Tribocorrosion characterization reflected the endurance of the surface oxide when the process parameters were adjusted. In addition, wearing simultaneously reflected the mechanical condition as the surface repassivate. The production of fragmentation film during wear caused accumulation of the corrosion product and demonstrated the effect of aggressive ions on the chemical and mechanical properties of the passivation film.

Improved tribocorrosion performance of bio-functionalized TiO2 nanotubes under two-cycle sliding actions in artificial saliva.

After insertion into bone, dental implants may be subjected to tribocorrosive conditions resulting in the release of metallic ions and solid wear debris, which can induce to peri-implant inflammatory reactions accompanied by bone loss, and ultimately implant loosening. Despite the promising ability of TiO2 nanotubes (NTs) to improve osseointegration and avoid infection-related failures, the understanding of their degradation under the simultaneous action of wear and corrosion (tribocorrosion) is still very limited. This study aims, for the first time, to study the tribocorrosion behavior of bio-functionalized TiO2 NTs submitted to two-cycle sliding actions, and compare it with conventional TiO2 NTs. TiO2 NTs grown by anodization were doped with bioactive elements, namely calcium (Ca), phosphorous (P), and zinc (Zn), through reverse polarization anodization treatments. Characterization techniques such as scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and scanning transmission electron microscopy (STEM), were used to characterize the films. Tribocorrosion tests were carried out in artificial saliva (AS) by applying two cycles of reciprocating sliding actions. The open circuit potential (OCP) was monitored before, during, and after both cycles of sliding, during which the coefficient of friction (COF) was calculated. The resulting wear scars were analyzed by SEM and EDS, and wear volume measurements were performed by 2D profilometry. Finally, the mechanical features of TiO2 NTs were accessed by nanoindentation. The results show that bio-functionalized TiO2 NTs display an enhanced tribocorrosion performance, ascribed to the growth of a nano-thick oxide film at Ti/TiO2 NTs interface, which significantly increased their adhesion strength to the substrate and consequently their hardness. Furthermore, it was discovered that during tribo-electrochemical solicitations, the formation of a P-rich tribofilm takes place, which grants both electrochemical protection and resistance to mechanical wear. This study provides fundamental and new insights for the development of multifunctional TiO2 NTs with long-term biomechanical stability and improved clinical outcomes.

Wear model for describing the time dependence of the material degradation mechanisms of the AISI 316L in a NaCl solution

The tribo-electrochemical behavior of AISI 316L has been investigated under tribocorrosion conditions in a 3% NaCl solution and the material damage evolution with time has been analyzed. A numerical contact model based on a Boundary Element Method (BEM) has been developed in order to determine the contact pressure distribution and to quantify the worn material as a function of time. The time dependence of the tribological behavior of the material has been described. At the initial state, the high contact pressures generate a material flow causing an increase in the worn area. After around 300 cycles, the Archard wear model linearly describes the wear evolution with time. The proposed model describes the evolution with time of the wear profiles of the tested material and takes into account the plastic behavior of the material during the first cycles.

Bio-corrosion behaviour of oxygen diffusion layer on Ti-6Al-4V during tribocorrosion

Oxygen diffusion layers (ODL) on Ti-6Al-4V were produced by thermal oxidation at a temperature of 850°C for three and six hours. ODL formation resulted in a β-Ti to α-Ti transformation, causing an increase in hardness. Polarization and EIS studies in stagnant and tribocorrosion conditions were performed under normal loads of 3–30N in a phosphate buffered saline solution. In a stagnant condition, a passive bilayer film was formed on samples, which led to a low icorr. During tribocorrosion, the formation of a protective tribofilm resulted in a higher Ecorr and a lower icorr in ODLs compared with Ti-6Al-4V.

Tribocorrosion of friction-stir-welded Ti6AL4V in 3.5% NaCl aqueous solution

Ti6Al4V has extensive uses in the marine and biomedical industry. In some of these applications, corrosion is present with additional mechanical wear. Thus, the corrosion, wear and their synergistic properties were investigated in applications where there were specifically induced material property changes, such as in welding. One such welding technique, friction-stir-welding, is a well-suited method for joining plates of the Ti6Al4V alloy. The purpose of the work was to investigate the effect of mechanical wear combined with electrochemical corrosion on the various weld zones of the material in a salt solution. The corrosive properties of the advancing side, retreating side and weld-zone regions of the material were compared to the properties of the parent material. The study showed that, when compared to the parent material, heat-affected zone and the weld zone, the advancing side was found to possess lower wear corrosion properties when compared to the retreating side. In addition, the weld zone was shown to have the lowest material loss per year under tribocorrosion conditions.

A comparative study of the mechanical behaviour of thermally oxidised commercially pure titanium and zirconium

The objective of this study is to compare the mechanical behaviour of thermally oxidised commercially pure titanium (CP-Ti) and commercially pure zirconium (CP-Zr). For this purpose, these two bio-metals were thermally oxidised under the same condition (650°C for 6h) and the oxidised specimens were characterised using various analytical and experimental techniques, including oxygen uptake analysis, layer thickness and hardness measurements, scratch tests, dry sliding friction and wear tests and tribocorrosion tests in Ringer's solution. The results show that under the present thermal oxidation condition, 4 times more oxygen is introduced into CP-Zr than into CP-Ti and the oxide layer produced on CP-Zr is nearly 6 times thicker than that on CP-Ti. Thermally oxidised CP-Zr possesses a higher hardness, a deeper hardening depth and better scratch resistance than thermally oxidised CP-Ti. Under dry sliding and tribocorrosion conditions, thermally oxidised CP-Zr also possesses much better resistance to material removal and a higher load bearing capacity than thermally oxidised CP-Ti. Thus, thermally oxidised Zr possesses much better mechanical behaviour than thermally oxidised Ti.

Tribocorrosion and Electrochemical Behavior of DIN 1.4110 Martensitic Stainless Steels After Cryogenic Heat Treatment

DIN 1.4110 martensitic stainless steel is largely used in the cutlery industry due to its high corrosion resistance associated with high mechanical resistance. However, when this material works under corrosion and wear conditions at the same time, their synergistic effect can accelerate the degradation process of the alloy. Cryogenic heat treatments have been proposed to improve the dimensional stability and mechanical properties, since they minimize the amount of retained austenite. The aim of this work is to study the effect of deep cryogenic heat treatment at -80 oC and at -196 oC on the corrosion resistance and tribocorrosion behavior of DIN 1.4110 martensitic stainless steel. The microstructure, hardness, corrosion resistance and tribocorrosion behavior were evaluated. Although the heat-treated samples presented higher hardness and lower corrosion current density (icorr) compared to samples in spheroidized condition, their material removal under tribocorrosion conditions increased, which demonstrated the synergy between corrosion and wear.

Characteristics of modified martensitic stainless steel surfaces under tribocorrosion conditions

Abstract Stainless steel samples were tested in the laboratory and under real conditions of tribocorrosion wear. Electrochemical tests were also carried out to verify the corrosion resistance of modified steel surfaces. Metallographic analysis and hardness testing were conducted on stainless steel samples X20Cr13 and X17CrNi16 2. The possibilities of applications of modified surfaces of the selected steels were investigated by testing the samples under real wear conditions. The results have shown that the induction hardened and subsequently nitrided martensitic steels achieved an average wear resistance of up to three orders of magnitude higher as compared to the delivered condition.

Electrochemical Behaviour of TiCN and TiAlN Gradient Coatings Prepared by Lateral Rotating Cathode Arc PVD Technology

TiCN and TiAlN gradient coatings were deposited on the AISI 316L stainless steel substrates by lateral rotating cathode arc (LARC) physical vapour deposition (PVD) technology. Corrosion and tribocorrosion behaviour was studied in 3.5 wt. % NaCl solution. The thickness of coatings was about 3 μm. For both coatings the corrosion potential shifted to more positive values as compared to the uncoated substrate. The corrosion current density decreased for TiCN and TiAlN coatings indicating up to 40 folds higher polarization resistance. The coefficient of friction value of TiCN coating is three times lower and durability is six times higher than that of TiAlN coating under the same tribocorrosion conditions.

Determination of selected properties and fracture toughness of HVOF coatings

Abstract The article is aimed at evaluation of chosen properties of thermally sprayed coatings based on tungsten carbide. It was evaluated two types of coatings – WC-FeCrAl and WC-WB-Co. The coatings were deposited on basic material steel AISI 316L. The aim of experimental works was to determine the quality and resistance of coatings in corrosion environment depending on number of thermal cycles. The quality of coatings was evaluated by determination of their adhesion depending on thermal cycles, determination of microhardness and indentation fracture toughness. Coatings were exposed in tribo-corrosion conditions with the presence of 1% NaCl. The results of experimental showed a higher quality of coating WC-WB-Co.

Wear and tribocorrosion behaviour of 304L stainless steel welds

The influence of the microstructures of the base metal and weld metals on the wear and tribocorrosion properties of 304L stainless steel (SS) welds prepared by Manual Gas Tungsten Arc Welding (M-GTAW) and Activated Flux Gas Tungsten Arc Welding (A-GTAW) processes are reported. Increase in sliding speed increased both friction forces as well as wear rate. Higher hardness in M-GTAW weld metal resulted in increased wear resistance than A-GTAW weld metal and base metal. The inferior wear resistance of the base metal was due to the strain hardening behaviour under sliding condition. The polarization curves showed increase in passive current density under sliding condition. The applied potential was found to influence the tribocorrosion resistance of the material. Under tribocorrosion condition, the total material loss was higher in base metal followed by A-GTAW weld metal and M-GTAW weld metal. Characterization of worn surface by SEM indicated a mixed wear mechanism of abrasive and adhesive wear. The worn surface appeared relatively smoother in nitric acid medium than in dry condition. The influence of microstructure affecting the hardness, wear and tribocorrosion resistance of the base metal and weld metals of 304L SS is discussed.

Study of Selected Properties of Coatings Devoted to Extreme Tribo-Corrosive Conditions

The paper deals with the evaluation of coatings CoMoCrSi and WC-NiMoCrFeCo applied by High Velocity Oxygen Fuel technology from point of view of their suitability for renovation of sink roll in hot dip galvanizing line. The structure of the coatings was evaluated by metallographic analysis. The adhesion of the coatings as-sprayed and after thermal cyclic loading was determined by pull-off test. Wear resistance of the coatings was evaluated by pin-on-disc test in the corrosive environment of 1M aqueous solution of NaCl.

Wear and corrosion resistant laser coatings for hydraulic piston rods

Hydraulic piston rods on oil and gas drilling platforms, hydro-power stations, chemical plants, and underground mines are exposed to severe tribo-corrosive conditions under static and dynamic mechanical loads. Piston rods made of carbon, quenched and tempered (QT) and stainless steels are frequently surface coated with methods such as thermal spraying, hard chrome plating, and overlay welding. Unfortunately, several premature failures have been reported particularly in marine applications due to insufficient coating properties. Laser cladding has recently drawn lot of attention in this field due to high coating quality and significant improvements in productivity. In this study, several potential Fe-, Ni-, and Co-based alloys were laser clad on carbon and QT steels. Their corrosion and mechanical performances were explored in long-term salt spray, immersion, hardness, abrasive wear, and four-point bending fatigue tests. Most of the laser coatings outperformed hard chrome in corrosion properties, but hardness values were somewhat lower. In single point abrasion tests (scratch tests), the hardest laser coatings, however, outperformed hard chrome due to brittle nature of hard chrome layers. Postmachining induced significant superficial hardness increases in laser coatings, which was the main reason for good wear performance. Fatigue performance was strongly dependent on material pairs, presence of cladding defects, and applied loads.

Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution

The tribo-electrochemical behavior of different β titanium alloys for biomedical applications sintered by powder metallurgy has been investigated. Different mechanical, electrochemical and optical techniques were used to study the influence of the chemical composition, Sn content, and the electrochemical conditions on the tribocorrosion behavior of those alloys Ti30NbxSn alloys (where “x” is the weight percentage of Sn content, 2% and 4%).Sn content increases the active and passive dissolution rate of the titanium alloys, thus increasing the mechanically activated corrosion under tribocorrosion conditions. It also increases the mechanical wear of the alloy. Prevailing electrochemical conditions between −1 and 2V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear of Ti30Nb4Sn.Wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys.